Stability experiments on models of Dutch and French standardized lifeboats

REPORT NO. 95 OCTOBER 1952

STUDIECENTRUM T.N.O., VOOR SCHEEPSBOUW EN NAVIGATIE

(NETHERLANDS' RESEARCH CENTRE T.N.O. FOR SHIPBUILDING AND NAVIGATION)

STABILITY EXPERIMENTS ON MODELS

OF DUTCH AND FRENCH STANDARDIZED

LIFEBOATS

(STABILITEITSPROEVEN MET MODELLEN VAN NEDERLANDSE EN FRANSE GNORMALISEERDE REDDINGBOTEN)

By PROF; IR H. E. JAEGER PROF. IR J. W. BONEBAKKER j.. PEREBOOM in collaboration with A. AUDIGE

"Ingénieur en chef du GénieMaritime"

"Ingénieur au ,Centre de Recherches de la Construction Navale" at Paris

INTRODUCTION AND SUMMARY

Early in 1950 Prof. Ir H. E. JAEGER, Chairman of the International Standards Organisation's Technical Committee 8 (I.S.O.-T.C. 8) (Standardisation of Sea-going Vessels) put forward the proposition to investigate the stability of ships' lifeboats by öarrying out model experiments. Subsequently, these investigations

were entrusted to Prof. JAEGER'S colleague at Deift University, Prof. Ir J. W.

Bo-BAKKER, whose laboratory had at its disposal the required apparatus.

Seven models were made. Five of these, representing Dutch standardized lifeboats, were constructed at Delft University.:

The other two, representing French standards, were made in France and dispatched to Holland through the courtesy of Mr A. AUDIGE, Ingénieur au Centre de Recher-ches de la Construction Naväle, Paris, and French delegate to LS.O.-T.C. 8.

The characteristis of the seven lifeboats se1ectd for these model experiments are listed below.

The models were exact replica's of the actual lifeboats, with seats, aircases etc. to

scale.

Each model was tested in ten different conditions, vizi carrying 50 percent, 75

percent or 100 percent öf its full complement, and in each case being either without

loose water, or flooded up to 10 percent or 100 percent of its volume. The tenth condition represented the boat in dry còndition, carrying 50 percent of its full

complement, shifted to one side:

The human beings were represented by tubes, the length volume and weight of which were calculated in accordance with the length volume and weight of the

human bodies.

The experiments were actually carried out by Messrs. J. PEREBOOM and D. J.

SCHOLTEN, who also prepared this report, which contains the following chapters:

1. BASIC PRINCIPLES OF THE INVESTIGATIONS.

2, THE LIFEBOATS AND THEIR MODELS

THE APPARATUS. (KEMPF'S Indicator of moments)

THE RESULTS OF THE EXPERIMENTS. PRELIMINARY CONCLUSIONS.

GENERAL REMARKS.

Lifeboat Model

Standard. Nr Fullness Dimensions Scale Material

Dutch 1 .67 4.50 x 1.80 x 0.72 13 1: 3 wood

,.

1 .60 430 x 1.80 x 0.72 12 1: 3 9 .67 8.00 x 2.80 x 1.15 61 1: 5 French 9 15 K .60 .67 .67 8.00 x 2.80.x 1.15 9.50 x3.20 x 1.22 8.50 x 3.00 x 1:21 54 87 73 1:5 1: 6 1: 5 ,, ,, light alloy P .67 9.50 x 3.40 x 1.30 1 : 5

BASIC PRINCIPLES OF THE INVESTIGATIONS

The drafting of international standards for ships'

lifeboats figures on the program of the

Inter-national Standards Organization's Technical

Corn-mittee 8 (I.S.O.-T.C. 8). Adequate stability is

required for these boats by the London Convention of 1948 on the safety of life at sea. So there is sound

reason for investigations into the latter subject.

Considering the scope of these investigations as detailed in the introduction, it will be obvious that mere calculations (apart from the enormous amount of time to carry them out) would lead

nowhere. Model experiments are considered to be the only means of getting reliable stability curves of lifeboats in the conditions specified. in the pre ceding introduction.

These conditions are rather complicated in an

actual emergency. Nevertheless they should be represented in the models as nearly as possible "true to life". Some simplifications seem to be unavoidable, without being detrimental to the

results of the experiments. For instance, in actual

life, the persons on board a lifeboat, may vary widely in size and weight; some may be seated, others standing upright; and there will be some

shifting of their positions.

In the experiments, the human beings are repre

sented. by tubes of length to scale; the volume and weight of the bodies being répresented to scale by using the required number of tubes and where

necessary - by sandfilling in the tubes to obtain

the required weight.

The apparatus used for ascertaining the righting

moments of the models at heeling angles ranging from zero to 90 degrees is described in Chapter 3. A more detailed description may be found in the following publications:.

Schiffbau 1913, page 239.

CHAPTER I

Jahrbuch der .Schiffbautechnischen Gesellschaft 1929, page 257.

Jahrbuch der Schiffbautechnischen Geselschaft

1935, page 91..

Schiff und Werft 1944, page 72.

From the model's curve of righting moments, the lifeboat's curve of righting levers may be deduced.

This curve will be normal till an angle q is reached

where the gunwale touches

the water level.

(see fig. 1)

II

Fig. i

Immediately hereafter water will enter the boat

causing it to sink deeper, and, as there is free

communication between the water in- and outside

the boat, the cntre of buoyancy is found to be

the common one of the hull and, constructive

parts, the. airtanks and the outfit of the boat and

of the passengers in the boat, as far as these

elements are immersed; the position of this new centre of buoyancy will be nearer to the centre

plane than in the case of the. boat not yet flooded

but at practically the same angle of heel, and

consequently the stability lever suddenly decreases

when the flooding begins. After this decrease the

cürve of levers shows a normal character.

When. the boat is coming back from its maximum

angle of heel, it is clear that at corresponding angles, the same values as before are found for the stability. levers, up to q, but now there will

.4

not be an increase to its former value at this angle,

but the curve will continue without a sudden

change up to q, where the gunwale emerges from the water. Here again the stability lever suddenly changes on account of the water which remains in

the boat and as there is now no longer a com-munication between the water in- and outside the boat, there will be again a shift of the centre

of buoyancy. Whether the stability lever

will

increase or decrease at this angle q. depends

chiefly on the form of the boat and therefore is.

impossible to predict without detailed particulars of the boat being available.

In the second case - water to the extent of 10% of the boat's volume being on board - a similar

curve may be expected, but ç will be smaller on

account of the greater draught. The part of the

curve corresponding to decreasing angles - from

q,,, back to q = .0 will be exactly the sanie as

in the first case.,

In the third condition - the boat full óf water the gunwale will be just level with the. outside water surface in most cases; the corresponding

curve of stability levers will be as represented in

fig. 2. In this case there will be no sudden shifts

Fig. 2

in the position of the centre of buoyancy. Again, the part of the curve . of levers corresponding to

decreasing angles from q)max.back to q) = 0, will

be exactly the same 'as in the first case

The model is fixed to the "indicator of moments" by meaiis of a.. connecting piece or "modeihead". This "modelhead" forms part of the model during the experiment and is to be accounted forin the

alcu1ation of the weight and the centre of gravity

of the model. As the centre of. gravity of this

"modelhead" is at some distance from the centre

plane of the model, the centre of gravity of the

whole is in an eccentric position as well. Conse-quently, at 92 = 0, an initial momentwill be the result, and all further readings (mq)) are to be

corrected for. this initial moment (m0): Assume the heeling angle to be q) (fig. .3);

p

Fig. .3

p weight ofmodel ± "modelhead" = (I.) Pm = weight of model + passengers.

Pmi = weight. of "modelhead".

g centre of gravity of model + ,,modelhead".

g= centre of gravity of model + passengers.

gmh = centre ofgravity of "modelhead".

centre of buoyancy at heeling, angle q).

m,= p.h

.

...(2)

p.ng'.sinq) + p.gg'.cosq (3) In the upright position (q) = 0):..

m0 =..p.h0 = p.gg' ...(4)

From ('3). and (4):

p.ngsin' 9) = m0 - cos

(5)

During the experiments the draught . and the

height of metacentre above keel (= m k) of the model are corresponding to the actual full-scale situation. So mk may be taken from the

hydro-static curves. But the height of the centre of

gravity above the keel

_{. (=} g'k) has nothing in

common with that of the actual boat, as 'the

distribution of weights for the model is different from that of the full-scale:, boat. This causes no difficulties, for by extrapolating to q)

= 0, the

value of ng':atq) = O may be found. As this is the metacentric .height of the model (mg'), and

g'k=mk.mg'...(6)

g'.k is known as well.

From equations (5) and (6) we find:

p.n.k.sin q, = p.ng' sin q)'+ .g'k.sin q) . (7)

Ifa = model scale, we find for the full scale boat:

P.NKsin97

= a.p.nk.sin

q) . .

...(8)

and the righting:moment of the actual boat will be:

.P.NK.sin 92-- P.GKsin q) = M9, . . (9)

where P .= weight of the actual boat

G = its centre of gravity, the position of

Accordingly, the righting lever for the actual boat

will be:

M9,

P

The foregoing still holds good during the

period when water has free access into the boat,

only it should be noticed that there will be a

shift of f9, and F9, when water is entering into the

boat, causing a drop in the curve of righting levers.

The picture will change, however, when there is

no communication between the water inside and

outside the boat, i.e. when the boat is partially

flooded from the outset. (fig. 4) If now:

Fig. 4 -.

= total weight of model + ccmode1head +

passengers + water = the buoyancy. f9, = the centre of buoyancy of the model.

b = weight of model + "modeihead" +

pas-sengers.

w = weight of the water inside the model.

p=b+w

(10)

g' = the projection of the common centre of

gravity, of the model, the "modeihead" and the passengers on the boat's centre plane, as

indicated in fig. 3,

g1 = the centre of gravity of the water inside the

model,

then the righting moment is represented by

p.no.sin ç + b.og'sinq'

(li)

or p.no.sin q, + b.ok.sin

q' -

b.g'k.sin q,. .

(lia)

and this is the righting momentm,?, of the model,

as measured by the apparatus, but corrected for

initial moment m,. Hence

m9, - m0 cos q, = p.no.sinq' + b.ok.sin

q'

-b.g'k.sinq . . _{. (12)}

As g'k is already known (see above)

we may

calculate:

mç, - m0cos 92 .± b.g'k sin q' p.no.sin q'+

b.ok.sinq, (13)

The elements of the righthand part of this equation are dependent on dimensions only and consequen-tly this expression may be multiplied by a4 when transforming the model results to actual size. By subtracting B.GK.sinq' (full scale dimensions)

from both parts of the resulting expression the

righting moment for the actual boat is found, and by dividing this moment by P the righting lever is

obtained.

In the case of the model without any water

and with only half the total number of passengers,

but all of them' seated on the lower side, the

initial moment will be:

m0 = p.h0 = p.gg' (fig. 5) (14)

Fig. 5

and m9, = p.h9, (fig. 6) (15)

For the mOdel in symmetrically loaded condition

Fig.6

the common centre of gravity of model, passengers

and modeihead is always at some distance gg'

from the centre plane on the side of the modelhead,

and in this direction gg' is

taken as positive; 5

accordingly m0 is positive as well.

In an asymmetrically loaded condition, as in the

case of the

model without any water and

with only half the total number of passengers but

all of them seated on the lower side, gg' may be

either negative or positive.

Therefore:

h

=

ng' sinq' ± gg' cosq' (fig. 6) . . (16)

and from (14), (15) and (16):

p.ng'sin q' =

m,

m0 cos q' (17) The value of g'k is calculated in exactly the same

way as already described. So again it is possible to

calculate pnk.sin q' and by multiplying this by

a4, the value of P.NK.siñ q' is found.

Obviously, considering the actual boat (fig. 7), the

Fig. 7

righting lever H9, is defined by

H9,

=

(NK.sin

q' -

G'K.sin q,) - GG'cos

q'

(fig. 7) . . . (18)

If it is assumed that G shifts only in a horizontal plane, then the value of G'K is already known and

it suffices to determine the value of GG' as has

been done fôr all cases (see chapter 2).

As long as there isT communication between the water inside and outside the boat, this method of calculation holds good.

When the boat is partially flooded the method of calculation has to be altered slightly.

atq' = O the initial moment is:

m0

=

p.h0 (fig. 8) . . . . (19) atq' O the moment as measured is:

m,

=

p.h, (fig. 9) (20)

Taking the moments about an axis through g1:

=

± b.gg' (fig. 8) (fig. 9) . . . (21) and m

=

p.nosinq' + b.ok. sin

q' -

b.g'k.sin q'

E b.gg'cosq' . . . . (22)

or m9, ni0.cosq' = p.no.sin q' + b.ok.sinq'

b.g'k.sinq'

(23)

Fig.8

Fig.9

Fig. 10

In this equation g'k has the same value as already

calculated for the model without any water in it. If now b.g'k.sin q'

is added to m,

m0.cos q'

the following equation is obtained:

b.g'k.snq .

of which the lefthand part is equivalent to p.nk.

sin q f6r the model without water in it and

there-fore is to be mtiltiplied by a4 tot get the

correspon-ding values for the actual boat.

As already stated, the boats which were tested, are all specimina of the Dutch and French series

of standardized lifeboats, of which the dimensions

añd other particulars, such as the total weight

(passengers included), allowed number of

pas-sengers, details of construction etc., are to be found

in the respective Standard Specifications:.

There are 15 boats in each series, the majority having a "fullness" of 0.60 or. 0.67. It not being

feasible to

test some 60 models, ' a

selection

had to be made. Therefore

it was agreed to

investigate the most representative boats of these

series. As the French bôáts are almost similar to the Dutch ones, it was agreed that of the Frènch

series, models should be built of 2 light-alloy

lifeboats, viz, the nos. K. and P1

Of the Dutch series only the smallest, the biggest

and an intermediate size

were proposed . for

testing, viz, the nos. l-9-15, the nos. 1 and 9 for

2 coefficients of fullness, all 5 models. 'representing wooden boats.

A body plan of the boat no. 9- 0167 is reproduced

in fig. 14, at the end of this report. Particulars of

thesè Dutch boats and their models are to be

found in the. Tables I - X.

The scale of the. models had to be decided on in

accordance with the maximum righting moment to be expected and with the dimensions' of the basin. (The apparatus used should not be loaded

with moments over 675 kg.cm. (see chapter 3.) Accordingly the model-scale for the French boats

wasfixedat

1:5

and ,for the Dutch boats:

fOrno. lat

. '

1:3

for no.

9 at

1 :5

forno.l5at'

1:6

With regard tO the occupants in the boat it will be cléar that it is impossible to make exact imitations

CHAPTER 2

PARTICULARS OF THE INVESTIGATED LIFEBOATS AND THEIR MODELS

'By subtracting ''.

B.G'K.sin + B.GG'cos (fig. 10) . .(25)

the actual moment, of stability of the full-size boat

is obtained. By dividing this moment by P the

actual lever of stability is found.

to ale, eVéñ if They are considered to be fixed to their seats. Nevertheless it is' absolutely necessary,

as explained in the preceding chapter, to take into

account the volume and weight of the bodies of

the occupants. This has been doñe in the following

way: for a fully dressed human being the specific

weight will be equal to about 1. and the average weight about 5 kg, so the average volume will amount to about' 75 dm3

In order to obtain, in these experiments, a reason-ably close approximation ofthe actual conditions,

pipes closed at both ends and placed vertically

in the boat, have been used to represent the

occupants of a boat.

These pipes, having a diameter of 38 and 50 mm

respectively are oÌ' length corresponding to the

length of a man sitting in the boat.

Assuming the average length of men to be about

1.80 m., the length of the pipes for each model

depending on the scale, Ïïiay be cálculated as well as the volume. As the volume of the occupants is kn at 75 dm3 per oÇcupant and accordingly for

the model will be 75/a3 dm3 per occupant, the

necessary number of pipes may be computed for each case. Finally, by filling the pipes with sand, before closing, the exact weight for each loading condition according to the scale, is arrived at. In otder to be able to ca1c'Ülät the valuei of GK

and GG', it is necessary' to know how the total number of passengers is distributed

yr

e

thwarts, the higher and the lower seats. For this

purpose a report' of Ir V. KRZEMiNSKY àn' the design of metal lifeboats has been taken as a base. According to this report the number of persons on

the longitudinal seats and the' number on the

higher and lower transverse seats are in the pro-portion of 21: 22 : 32. Furthermore a practical British rule says that the height of 'the centre of

gravity of a sitting person above the seat is 12" or 303 cm.

Plans being available, the heigth of the: seats above

base-line could be measured..

The mean height of the higher seats was found to

be H 1/3 b and that of the lower seats 1/2 (H

-1/3 b) where b = height of top of gunwale above top of seat.

The lightweights of the boats (including inventory)

TABLE i

TABLE 2

as well as the GK-válües, have been obtained

from a calculation of weights and moments. Assuming the occupants to be distributed over the

various seats as mentioned above, it is possible

tot compute. the height of the common centre of

gravity as shown below for. boat no. 9 - 0.67. The lightweight of boat no. 9 -.0.67 = 2621.6 kg

and GK = 53.66 cm (inventory included). Com pletely manned she carries a complement of 61,

distributed over the seats in the proportion of 21 :22

:32 as mentioned above. As the longitudinal seats and the higher transverse seats are appròximately

on the same height above the base-line, the propor

tion for the higher and the lower seats may be

taken aS 43 : 32.

The centres of gravity of the persons on the higher

seats will be: H - 1/3 b +30.5 = 137 cm above the baseline, those of the persons on the lower seats are

1/2 (H - 1/3 b) + 30.5 = 83,75

ciii above the baseline.

A calculation of moments about the base-line

will give the required value of OK for the fully

manned boat, viz

2621.6 x 53.66+35 x 76 x 137 + 26 x75

x 83.75 = 7196.6 GK

.GK.= 92.21 cm..

For all other cases the GK-values are calculated

in the same way. The results are shown in Table 1.

A different, method of calculation had to be

applied to both the French boats, as no calculation

of weights was available. Only their lightweight

and corresponding OK-value .were known in

addition to the height of the centres of gravity

of the passengers above the base-line.

This made it possible, by means of a simple cal-culation of moments, to compute the OK-values,

which are lacking.

The results are shown in Table 2.

In the case of the asymmetrical loading

condi-tions álIe the occupants (.i.e. half the complement)

are assumed to.be..seated on the lower side. of the

- Numberof passengers GKin cm Lightweight: 2030 kg .36 . 90.4 K 55 96.6 GK = 55.02cm 100.3 Lightweight: 3175 kg 49 103.7 P 74 110.0 GK = 69.89cm 114.1 Boat no. 1 - 0.67 Lightweight: GK

H-1/3b +

(H- i/3b) + 866.85 kg = 36.73 cm + 30.5 + 30.5 = - =94.84cm =62.77cm number of occupants

to1

on higher

_Ss

on lower GK in cm.

.6 3 .. 3 5502 .10 6 4 63.41 13 7 6 65.87 Boat no. i - 0.60 Lightweight: GK

H- i/3b ±

(H- 1/3b) + 847.26 kg 38.45 cm + 30.5 = + 30,5 = - . 94.84cm = 62.77 cm 6- 3 3 56.42 4 62.40 12 7 5 .66.84 Boat no. 9 - 0.67 Lightweight: GK H 1/3b + -( H - i/gb) + 262 1.6 kg = 53.66. cm + 30.5 - + 30.5 = = 137 cm = .83.75 cm 31 1 13 45 26 19 89.58 61 35 26 92.21 -- Boat no. 9 0.60 Lightweight:

..- H

1/31) + (H- 1/31)) ± 2431.4 kg = 57.09 cm + 303 = + 305 = -. . - 137 cm = 83.75 cm 32 18 . 14 - 85.21 41 23 18 88.66 54 31 23 92.85 - -Boat no. 15 - 0.67 Lightweight: 3820.9 kg GK = 68.98 cm

H - i/3b+

+

_-.

= 143.2 cm (H - i/3b) +

±

.5 -= 86.8 cm 51 29 22 --- r -65 37 28 96.97 7. .50 37. 100.66

TABLE 3

TABLE 4

TABLE 5

boat and as far from the centreplane as

practi-cable. This means that the centre of gravity

remains at the same distance above the base-line

as compared to the syinmetricaly loaded

condi-tion. As it is necessary to know the value of GG' for

this case, the seats and thwarts have been drawn

in the body-plans of the various boats. The space

The apparatus, as developed by KEMPF, consists

of a frame of bars with hinged joints in B, C, E, and

F and revolvable about the fixed pivot in A, as

shown diagrammatically in fig. 11. The friction in those joints is practically negligible.

The bar C B D carries a counterweight Q, so

that the common centre of gravity of the bar and the counterweight is in B. C E carries a

counter-CHAPTER 3

THE INDICATOR OF MOMENTS

available for each occupant is taken as 48 cm. To

represent the occupants half circles of 48 cm

diameter have been drawn in, on the seats, and

the centres of these half circles are assumed to

re-present the centres of gravity of the occupants. By a

simple calculation of moments about the centre-plane the value of GG' is determined. The results of these calculations are shown in Table 3.

For the calculation of B = weight of boat +

in-ventory + passengers, the approximate total

weight as given by the standard specifications

has been used. From this

weight the

light-weight of the boat may be derived by subtracting

the weight of the total number of occupants at

75 kg per person, while for each condition the

total weight B may be found by adding again the weight of the necessary number of passengers at

75 kg per person.

As b = B/a8 and the weight of flooding water

being:

w=

10% ofthevolumeoftheboat (seeN 777; s.w. = 1) a3

P and p are known as well.

The volume of the necessary number of pipes,

representing the occupants, may be found from: number of passengers x 75

x 1000 cc. a3

The draught t, of the model, is to be measured

during the test. The value of m.k, corresponding

to this draught, is to be taken from the graphs of

mk-values for the various models, as represented

in fig. 13.

weight Q so that the common centre of gravity of C E and Q is in E.

By means of a counterweight Q on BF, the common centre of gravity ofCBD, Q5,BF and Q2 is fixed in F.

Lastly, the main bar M E F A K carries the

coun-terweights Q and Q so that the common centre

of the complete apparatus js exactly in A, whatever its position. Boat GG' in cm Boat GG' in cm i -0.67 12.71 15 -0.67 24.57

1-0.60

11.83 K 35.54

9-0.67

24.32 P 41.39

9-0.60

26.41

Boat Mean % of total buoyancy_{per passenger}

1 -0.60 45.3 1 -0.67 46.7

9-0.60

53

9-0.67

53.1 15-0.67 59 i

ii

ii

v-ïïí-

y

VI -(1+111)

Vol. of Effect. Total Necessary Total Tanks Boat struct. vol. of weight capacity voL of % of

-5% occu- of tanks boat total

pants volume dm' dn Kg dm' dm' 1-0.60 617 407 1650 626 3500 17.89 1-0.67 637 465 1840 739 3907 18.91 9-0.60 1776 2145 6060 2139 15450 13.85 9-0.67 1919 2425 6810 2466 17260 14.29 15-0.67 2793 3850 9740 3997 2400 12.50

Fig. 11

Therefore the apparatus will always be in a

con-dition of indifferent equilibrium, provided no

model is fixed to it.

The bars M E F A and C B D will always be

parallel to each other, whatever their position.

As soon as M E F A departs a little from its

vertical position, a circuit is closed causing either

the telltale lamp L1 or L2 to burn, dependent on the

direction of inclination of M E F A.

If M E F A is in exactly vertical position, there

will be no light.

Now the model is fastened by means of the con-necting piece or "modeihead" to D. The draugh:t of the model is not influenced by this.

By means of a special universal joint at D, however,

the model is free to trim and by means of a

hand-wheel H the model may be adjusted to any

required angle of heel, q,.

A forced angle of heel q,, brings about a stability

moment P.h, causing the apparatus to depart

from its original position.

By loading the lever A K in K with a weight G,

a moment G.a. is set up counterbalancing the

stability moment P.h. When G.a. = P.h the bars

C B D and M E F A will remain in a vertical

position and no electric circuit will be closed so

that neither L1 or L2 will flash.

When G.a is not exactly equal to P.h on one or the other side the circuit will be closed causing

either L1 or L2 to flash.

The distance between the contacts is adjusted to ade-greeofprecision of the apparatus of about 0.1 kg. cm.

For reasons of strength the apparatus has a limited

range and should not be loaded by moments

exceeding 675 kg.cm.

Summarising it may .be sáid that it is possible. t measure the stability moments of a model for any required angle of heel q,, with sufficient accuracy,; by measuring the moments G.a.

30 25 20 15 10 mk In cm 11 Fig. 12

REQUIRED MINIMUM VOLUME OF BUOYANCY TANKS

IN % OF VOLUME OF BOAT ON GUNWALE

REQUIRED MINIMUM PERCENTAGE CALCULATED

AS

.

PROPOSED MINIMUM PERCENTAGE

-: - - -

-

-EQUATION L

--

- .

-(SEE TEXT)

-\

\

\\

CURVES OF MK.VALUES (FO MODEt.S)

FIg. 13 -. 1-0.60 9060 1 0.67 K 0.67 --P-0,67 15 0.6 9-0,67 VOLUME OF BOAT IN dm 5000 10000 15000 20000 25000 25 30 40 14 13 12 11 10 Q e E

Instances of the cniculation of the stability levers

are shown in Table XI.

According to the standardization rules, the capa-city of the airtanks in lifeboats should not be less

than 10% of the volume of the boat up to the

gunwale.

This investigation shows, however, that for the

standardized Dutch boat no. 1, this percentage is

insufficient. Of the other Dutch boats it may be.

said that they keep afloat but with gunwale

completely submerged.

In circumstances like that it is rather doubtful whether the occupants (who provide their share

in the buoyancy) would remain seated.

The airtanks not only supply the necessary reserve

buoyancy, but serve to improve the stability as

well.

If, however, before the boat is completely flooded, the occupants were to leave it for fear of drowning,

the function of improving the stability would be

meaningless. Buoyancy should be . considered in the first place.

Therefore it is proposed to increase the

reserve-buoyancy, by increasing the capacity of the.

airtanks to such a percentage, that when fully

flooded, the boat will be immersed to the top

of the gunwale at the midshipsection.

The French light-alloy boats need not be consi-dered separately,

as the required buoyancy of

CHAPTER 4

RESULTS OF THE EXPERIMENTS.

CHAPTER 5

PRELIMINARY CONCLUSIONS

The results of the experiments are plotted in the

graphs IXXVIII.

these boats should not be less than that of the

corresponding wooden boats.

From the calculation of weights of the various

boats the volume of the structure of the boat

(inventory included, but capacity of airtanks

excluded) may be derived:

Boat no.

1 - 0.60

650 dm3

Boat no. 1-0.67

670dm3

Boat no.

9 - 0.60

1870 dm3

Boat no.

9 - 0.67

2020 dm3

Boat no. 15 - 0.67 2940 dm8

In fully flooded condition the total buoyancy

consists of volume of structure, capacity of

air-tanks and part of the volume of the occupants.

As the capacity of the airtanks is assumed to

balance the difference between toi al weight of the

boat and the buoyancy of structure and

passen-gers, only the item "occupants" will be examined

moré closely.

In the completely flooded boat, the occupants are

only partly submerged, consequently the buoyancy

per person is less than his weight.

From this it is clear, that the most dangerous

situation may develop for the fully manned boat;

for each occupant less, the reduction of weight

will be more than the reduction of buoyancy.

the volume of the occupants is actually

contri-buting to the buoyancy of thé boat.

According to the report of Ir V. KRZMINSKY, mentioned above, the total volume of a human

body is

distributed over its various parts in

approximately the follwing proportion: 28% for

the trunk, 32% for the legs, 20% for the head

and 20% for the arms.

The heigth of a sitting man above thè seat may

be assumed to be 85 cm.

As already mentioned, the height of the higher

seats is found to be H - 1/3 b above the baseline, and of the lower seats:

/2 (H - 1/3 b).

If boat no. i is taken as an instance, the following calculation can be made.

The heights of the seats above the baseline are

64.34 cm and 32.17 cm respectively.

The height of the occupants sitting on the higher

seats *111

be 64.34 + 85 = 149.34 cm above

baseline and of those on the lower seats 32.17 +

85 117.17 cm.

As the depth to top of gunwale amidships is

72 cm, the height above waterlevel of the

occu-pants on the higher seats therefore is:

149.34 - 72 = 77.34 cm.

This means that only their legs are submerged and only 32% of their volume is cOntributing to

the total buoyance.

Of the occupants sitting on the lower seats the

height above waterlevel is only

117.17 72=45.17cm.

So not only their legs are submerged but part of

85-45.17

their trunks äs well, viz.

20% + 20%) = 32%.

Therefore 64% of their volume is' contributiñg to

the tOtal buoyancy.

As in boat No. 1 0.60 there are 7 occupants on

the higher seats and 5 on the lower seats, the

mean percentage of his volume each occupant is

contributing to the total buoyancy amounts to:

7 x 32 + 5 x 64

= 45.3% 12

85

x (28%±

These mean percentages as calculated for the

various boats are shown in Table 4.

From these mean percentages the buoyancy,

contributed by the passengers in the completely flooded boat, may be computed; it is denoted as

"effective volume."

The volume of an occupant is assumed to be

75 dm3.

For boat No. 9 - 0. 60 with a complementj of

54, for instance,

the effective volume of the

occupants is 0.53 x 54 x 75 dm3 = 2145 dm3. The specific gravity of water is taken as I, thus

providing a certain reserve in the necessary capa-city of the airtanks.

In Table 5 are shown the effective volumes of the

occupants and the necessary capacities of the

airtanks for the various boats. (5% of the volume

of the structure has been allowed for those parts

of the hull which, are above the waterlevel when

the boat is submerged up to the top of the

gun-wale amidships).

In fig. 12 the necessary capacity of the airtanks

for the various boats is plotted as a percentage of the volume of the boat.

The resulting graphs represent the required minimum capacity of the airtanks.

In order to improve the safety of the lifeboats an increased percentage is proposed.'

In fig. 12 this increased percentage is represented

by a straight line and may be expressed by the

equation:

63000V

3000

where V = total volume of boat in dm3 up to top

of gunwale amidships.

L = capacity of airtanks expressed in %

of V.

It is proposed that in future the capacity of the

airtanks for all lifeboats should be required to be

not less than the percentage derived from this

equation, as this minimum percentage may be

assumed to guarantee adequate buoyancy.

It will be observed that in some cases the graphs

show higher values for the stability levers of a boat in fully flooded condition than for those of

the same boat in the ,,l0% flooded" condition

(e.g. boat no.

15 - 0.67 and No. 9 - 0.60).

Though this may seem rather paradoxical, there

is a simple explanation for this phenomenon.

In fig. 4 is shown a model in the ,,l0% flooded"

condition.

The stability lever depends on the positions of

Ç and the common centre of gravity of the model

including the occupants and the flooding water. This common centre of gravity is the resultant

of g' and, g1, so the lever may be said to depend

on the positions of Ç, g' and g1. (see equations

I l-13).

When in the fully flooded condition, there is a free

communication between the water outside and inside the model; than the buoyancy is mainly

made up of the immersed parts of the

áir-tanks and therefore f9, in general will shift towards

the centre-plane, which would tend to reduce

the righting lever. But on the other hand the

water inside the boat is no longer to be treated as "lost buoyancy" but as an "added weight".

Therefore the lever is now dependent only on Ç and g'.

This may cause an increase of the value of the

stability lever. In the case of the .boat in the 10%

flooded" condition with the occupants all seated on the lower side, the stability levers may attain higher values than in the case of the dry boat in

the same condition.

This may be explained by the circumstance

f

the passengers on. the lower side occupying part of the space, available for the flooding water. Accordingly the position of the centre of gravity,

g1, of the flooding water may be somewhere in the

CHAPTER 6

GENERAL REMARKS

higher half of the boat. This may mean 'an

in-crease of the stability lever as compared with the

boat in the same condition but without water.

Even in the fully flooded condition, with all the occupants seated on the lower side, the stability levers may attain higher values than in the case

of the dry boat in the same condition. Because of the occupants n the lower side contributing to the buoyancy, whereas there is no such

contri-bution on the higher side, the centre of buoyancy, Ç, may be at a greater distance of the centreplane than in the case of the dry boat.

With regard to the degree of accuracy of the

results; the following remarks may be made.

If the indicator of moments is assumed to give correct readings, the method of computing the

results may cause some errors. Firstly the way in which g'k is obtained, by extrapolating the values

of ng' to q = 0, can not be guaranteed to give

the correct results and errors of I - 5% are not impossible. This hs o be accepted, however, as

no other, more accurate way of computing g'k is

available.

Secondly, the calculation of GK and GG' can of

course not claim to be free of inaccuracies.

Lastly, there is the impossibility to make the test a life like imitation of the. actual conditions.

One of the factors affecting the position of the centre of buoyancy of the fully flooded boat, is the distribution of the occupants over the boat, and for the model the distribution of the

ballast-pipes.

It is too farfetched to suppose that the position

off9, in the model will correspond to that of F9, in

the actual condition. as the exact position of F9,

is not even known. .

The same remarks apply to the position of g,,,

TABLE II. Data of model and prototype. Boat 9- 0,67 a = 5.

TABLE III; Data of i odd and prototype. Boàt 9 0,6Ò. a = 5.

TABLE IV. Data of model and prototype. Boat i - 0,67. a =

TABLE V. Data of model and prototype. Boat i - 0,60.

p. =w±b

b = weight of model + ballast

w = weight of water inside model

t = draft of model as measured

mk = taken from hydrostatic curves mg' = derived from curve of ng' - values

g'k = height of centre of gravity above base for dry model GK = height of centre of gravity above base for prototype

(dry) (calculated) Number of passengers - -In loading condition Model . -Prototype b kg w kg p kg Volume of ballast cm3 t mm mmmk mg' mm mmg'k B=b.a'kg . P=p.a3 kg GK cm 51 A Dry 32,500 32,5001 17708 82 279,5 :72,3 207,2 7040 7040 93,94 B 10% Flooded 32,500 11,481 43,981 17708 103 207,2 7040 9500 9394 100% Flóoded 32,500 32,500 17708 207,2 7040 7040 93,94 65 A Dry 38,360 38,360 22569 93,5 272,5 55,1 217,4 8286 8286 96,97 B 10% Flooded 38,360 11,481 49.841 22569 113 217,4 8286 10766 96,97 100% Flooded 38,360 38,360 22569 217,4 8286 8286 96,97 87 AI Dry 47,266 47,266 30208 107 264,5 50,5 2 14,0 10209 10209 100,66 B 10% Flooded 47,266 11,481 58,747 30208 127 214,0 .10209 12689 100,66 C 100% Flooded 47,266 47,2661 . 30208 . 214,0 10209 10209 lOO66 31 A Dry 36,480 136,480 18600 98,5 282 76 206 4560 4560 82,33 B 10% Flooded 36,480 13,808150,288 18600 112 206 4560 6286 82,33 C 100% Flooded 36,480 136,480 18600 206 4560 4560 82, 45

j

Dry 44,880 _44,880 27000 104,3 268,4 63,7 204,7 5610 5610 89,58 i] 10% Flooded 44,880 13,808158 688 27000 128,8 204,7 5610 7336 89,58 cl 100% Flooded 44,880 148,880 27000 204 7 5610 89,58 61 A Dry 54,480 I54480 36800 120 258,4 49,5 208,9. 6810 6810 92,21 B 10% Flooded 54480 13 808168,288 36800 139 208,9 6810 8536 92,21 92,2F C 100% Flooded 54,480 54,480 36800 208,9 6810 6810 32 D 35,740 35,740 19086 96 269 I 49 220 4467 4467 85,21

ä

10% Floodéd 35,740 12,360 48,100 l9086 118 I 220 4467 6012 I85,2i 100% Flooded 35,740 35,740 19086 I 220 4467 4467 85,21 41 A Dry 41,300 41,300 24600 106 268 32 236 5162 5162 I8,66 B 10% Floóded 41,300 12,360 53,660 24600 . 127 236 5162 6707 88,66 C 100% Flooded 1,300 41,300 24600 . 36 162 516 54 A Dry 50,350 50,350 32400 121 266 34,15 231,85 6294 6294 I 92,85 B, 10% Flooded 50,350 12,360 62,710 -32400 140 I 231,85 6294 7839 92,85 C 100% Flooded 50,350 50,350 32400 I 23 1,85 6294 6294 92,85 6 A Dry 48,333 48,333 16650 98 308 59,70 248,30 1315 1315 55,02 B 10% Flooded 48,333 14,481 62,814 16650 126 288 248,30 1315 1706 55,02 C 100% Flooded 48,333 16650 248 30 1315 55,02 10 A Dry 59,815 59,815 27778 121 291 30,60 260,40 1615 1615 63,41 B 10% Flooded 59,81514,481 74,296 27778 143 280 260,40 1615 2006 63,41 C 100% Flooded 59,815 27778 .

00

1615 63,41 13 A Dry 168,148 68,148 36111 - 133 285 : 55,00 230,00 1840 1840 65,87 B '10% Flooded 168,148 14,481 82,629 36111. 158 275 230,00 1840 2231 65,87 C 100% Flooded 168,1481 36111 - .230,00 1340 .65,87 6 AI -: Dry 44,470 44,470 16650 107 281 17,73 263 1200 1200 [56,42 10% Flooded 44,470 12,963 57,433 16650 _{129,7 269} 263 1200 1550 56.42 cl 100% Flooded 44,470 44,470 16650 263 1200 56,42 9 -A Dry 52,780 .52,780 24975 115 271,5 21,25250,25 1425 1425 62,40 B- 10% Flooded 52,780 12,963 65,743 24975 143 266 250,25 1425 1775 62,40 C 100% Flooded 52,780 52,780 24975 250,25 1425 62,40 12 Al Dry 61,111 _61,1111 33300 140 266 23,50 242,50 1650 1650 66,84 B 10% Flooded 61,111 12,96374,074 33300 159 264 242,50 1650 2000 66,84 C 100% Flooded 61,111 61,111 33300 242,50 1650 66,84

TABLE VI. Data of model and prototype. Boat 1 - 0,67. 6 passengers ôñ lower boat.side. a =

TABLE VII. Data of model and prototype. Boat I - 0,60. 6 passengers on lower boatside. a = 3.

TABLE VIII. Data of model and prototype. Boat 9 - 0,60. 32 passengers on lower boatside. a = 5.

TABLE IX. Data of model and prototype. Boat 9 - 0,67. 31 passengers ön lower boatide. a = '5.

TABLE X. Data of model and prototype. Boat 15 - 0,67. 51 passengers on lower boatside. a = 6.

p

=w+b

b = weight of model + ballast

mk = taken from hrd±ostatic curves

mg1 = deñved fromcurveof ng1- values

Number of pas-sengers -In loading condition Modeï - - Prototype b kg W kg p kg Volume of ballast cm3, t mm mk min mg' mm mmg' =b.a3 kg P=p.a8 kg G'K cm GG' cm 6 on lower boatside A Dry 48,480 48,480 16650 107 300 45,00 255,00 1315 1315 55,02 12,71 B l0%Flooded 48,48014,481 62,961 16650 128 287 255,00 1315 1706 55,02 12,71 100% Flooded 16650 255,00 1315 55,02 12,71 6 on lower boatside A Dry 44,444 44,444 16650 110 280 14,00 266,00 1200 1200 56,42 11,83 B 10% Flooded 44,44412,963 57,407 16650 131 269 266,00 1200. 1550 56,42 11,83 100% Flooded 16650 266,00 56,42 11,83 32 on lower boatside A Dry 37,030 37,030 19200 96 269 60 209 4629 4629 85,21 26,41 B 10% Flooded 37,030 12,360 49,390 19200 118 209 4629 6174 85,21 26,41 C 100% Flooded 37,030 37,030 19200 209 4629 4629 85,21 26,41 31 on lower boatside A Dry 37,860 37;860 18600 92279 86 193 4732,5 4732,5 92,21 24,32 B 10% Flooded 37,860 13,801 51,661 37,86d 18600 18600 112 201 193 193 4732,5 4732,5 6458,0 4732,5 92,21 92,21 24,32 24,32 C 100% Flooded 37,860 51 on lower boatside A Dy 32,800 32,800 17708 84278 56 222 7085 7085 93,94 24,57 B 10% Flooded 32,800 11,480 44,280 17708 101 222 7085 9564 93,94 24,57 C 100% Flooded 32,800 32,800 17708 222 7085 7085 93,94 2457

w = weight of water inside model g'k = height of centre of gravity above base for dry model t = draft of model as measured GK = height of centre of gravity abòv base for prototype

TABLE XI. Results of the experiments. Boat no. 15 -i-- 0,67.51 passengers. A = dry. Eb o °.. E is. ;E

hl

,!c..ns. - E

>J

l

. X. ii 'D. il ;E EcE lIZ Lever

...

iic. z 110 ,, 0 751 751,00 0,00 72,28 0,00 0,00 0 0 0 0,00 1 792 750,85 41,15 72,57 117,86 159,01 20608 11573 9035 1,28 2 832 750,55 81,45 71,92 235,04 316,49 41017 23079 17938. 2,55 3

T

T

873 749,95 123,05 72,47 352,22 475,27 61595 34586 27009 3,84 913 749,20 163,80 72,21 470,08 633,88 82151 46159 35992 5,11 952 748,15 203,85 71,90 587,26 791,11 102528 . 57665 44863 6,37 7 Ïö

Ï

1031 745,37 285,63 72,11 820,95 1.106,58 143413 80612 6280i 8,92 12,53 1137 739,58 397,42 70,45 1169,14 1566,56 203026 114802 88224 1284 725,39 522,61 62,13 1742,93 2265,54 293614 171144 122470 17,40. 1398 705,71 692,29 62,28 2303,25 2995,54 388222 226165 162057 23,02 25 d 1480 680,63 799,37. 58,21 2846,06 3645,43 472448 279465 19298.3. 27,41 1515 .663,06 851,94 55,83 3161,92 401386 520196 310480 209716 29,79 O 752 752,00 0,00 - 0,00 - 0,00 - O O OE 0,00 1 784 751,85 32,15 117,86 150,01 1941 11573 7868 0,83 2 808 751,55 56,45 235,04 291,49 37777 23079 14698 1,55 834 750,95. 83,05 . 352,22 - 435,27 56411 34586 21825 2,30 851 750,20 100,80 470,08 570,88 73986 46159 27827 2,93 5 880 749,14 130,86 587,26 . 718,12 93068 57665 - 35403 373 7 10 .922 iöö1 746,36 175,64 820,95 996,59' 129158 80612 48546 5,11 740,57 260,43 1169,14 1429,57 185272 114802 704.70 7,42 11,28 15 1131 726,36 404,64 1742,93 2147,57 278325 171144 107181 20 1251 706,56 544,35 03,25 2847,60 369049 226165 142884 15,04 23d 1318 692,22 ' 625,78 2631,23 .3257,01 422108 258370 163738 . 17, O' - 757 '757,00 0,00 - 0,00 0,00 0 O 0 0,00 1 754 756,85 -2,85 117,86 115,28 14940 ' 11573 3367 0,48 3 10 20 783 755,94 27,06 352,22 379,28 49155 34586 14569 2,07 830 898 754,12 75,88 587,26 663,14 85943 57665 28278 4,02 8,02 745,49 152,51 1169,14 1321,65 171286 114802 56484 971 711,35 259,65 ' 2303,25 2562,90 - 332152 226165 109587 15,57 20,55 956 655,56 300,44 3367,32 3667,76 475342 330650 144692' 40 701 579,86 121,14 4329,03 5158,745007,14 4450,17 576742 425084 151658 - 21,54 50 335 486,60 -151,60 . ' 648925 506556 142369 20,22 60' -57 378,50 -435,50 5832,21 5396,7 1 699414 '572686 126728 18,00 70 -574 258,89 .805,89 6328,55 5522,66 - 715737 621424 94313 13,40 17,42 60 92 375,00 -467,00 . 5832,21 5365,21 695331 '572686 122645 ' 320 482,10. .162,10 5158,74 4996,64 647565 ' 506556 '141009 20,03 '1 30 705 574,50 130,50 296,50 4329,03 4459,53 577955 425084 152871 21,71 946 649,50 3367,32 3663,82 2561,48 474831 330650 144181 20,48 20 963 704,77 258,23 2303,25 331968 226165 105803 15,03 lO 5 '889 820 738,60 150,40' 1169,14 1319,54 171012 114802 56210 7,98 747,15 72,85 587,26 660,11 85550 57665 27885 3,96

T

1

770 74895 21,05 352 22 373,27 48376 34586 13790 1 96 747 749,85 -2,85 117,86 115,01 14905 11573 3332 0,47 O 750' 750,00 0,00 0,00 _O,QQ,,, O O O 0,00

B 100/n flooded. b.g'k. sin B.GK. sin

¿30 25 z 20 15 lo s o 30 25 ç., z 20 15 10 5 o BOAT: 15-0,67 NUMBER OF PASSENGERS GRAPH. I 51 DRY FLOODED FLOODED

-10% - 100/

,

// C,

.7

..

_N.'.

N

BOAT: 15 - 0.67 NUMBER OF PASSENGERS: GRAPH; II 65 DRY FLOODED FLOODED 10% ._1Oß%

4,4:.

-.

H

60 7O RO 20 30 40 50 60 70 80

30 25 Q z 2Ó 15 lo s 25 Q z 20 15 10 5 o lo lo 20 20 30 40 50 50 60 60 70 70 q' 80 q' 19 BOAT: 15 - 0.67 NUMBER OF PASSENGERS: GRAPH. III 87

-

4

A

DRY FLOODED FLOODED

-10% ...100%

Alt

AIU

BOAT: 9-0.67 GRAPH. IV NUMBER OF PA$SENGERS:.31 DRY FLOODED FLOODED

-10% 100%

'7

f4

,

11A

pv

À.

.:i.

E 20 15 lo 5 o 20 15 10 5 10 _"1G 20 cm 30 40 50 60 70 9' 80 BOAT: 9 0,67 NUMBER OF PASSENGERS: GRAPH. V 65 DRY

-FLOODED FLOODED 10% _._100% ,çc'

,

,'

BOAT: 9 0.67 GRAPH. VI NUMBER OF PASSENGERS:61

- DRY

FLOODED FLOODED 10% _.._.100% C:" ' 9' iO 20 30 40 50 60 70

j30 25 L, z 20 15 lo 30 > w 25 z 20 15 10 5 o 5 o 21 BOAT: 9 0.60 NUÑBER OF PASSENGERS: GRAPH. VII 32 DRY FLOODED FLOODED

-10% __100%

/

BOAT:9-0,60 NUMBER OF PASSENGERS: 41 GRAPH. VIII - DRY FLOODED FLOODED 10% __100%

T

ì_

C,

z

-7

z

//

10 20 30 40 70 80 10 20 30 40 50 60 70

iö 20 30 - 40 50 60 70 BOAT: 9- 0.60 NUMBER OF PASSENGERS: GRAPH. IX 54 DRY

-FLOODED FLOODED ... 10% __100% //

7

/

411"

BOAT: I - 0.67 NUMBER OF PASSENGERS: GRAPH.X 6 - DRY FLOODED FLOODED 10% _._100%

,

_{- I}

.1

,,

20 30 40 50 60 70

E =_u.' >

i::

15 lo 5 o = 'u > 125 z 20 15 10 o 23 BOAT:l 0.67 NUMBER OF PASSENGERS: GRAPH. XI 10 DRY FLOODED FLOODED

-10% __l00% BOAT: I - 0.67 NUMBER OF PASSENGERS: GRAPH. XII 13 DRY

-FLOODED FLOODED 10% ...100% o 30 40 50 60 70 -Io 20 30 40 _5° 60 70 ç

:120 ff25 z 20 15 lo 5 o :120 ff25 z 20 15 10 BOA1:1 - O.6 NUMBER OF PASSENGERS: 6 GRAPH. XHI . DRY FLOODED FLOODED

-10% _.._100% F F F .1

V

F

/

BOAT:1-0.60 NUMBER OF PASSENGERS: GRAPH. XIV 9 DRY

-FLOODED FLOODED 10% _.._100%

_Icn

Io 20 30 40 50 40 50 60 70 20 30 10

w > 25 z 20 15 lo 5 o

5

10 15 25 BOAT: I - 0.60 NUMBER OF PASSENGERS: GRAPH. XV 12 FLOODED FLOODED

-

10% ..._100% __-1 FLOODED FLOODED BOAT: i - 0.67 NUMBER OF PASSENGERS: GRAPH. XVI

6 (ON LOWER BOATSIDE) 10%

_._100% 60 50 60

70,

80 10 20 30 40 50 60 70 q' 15 E

i

lo

5

lo

15

L:

ió

15 2G 25 BOAT:lO.60 NUMBER OF GRAPH. Xvii

PASSENGERS:.6 (ON LOWER BOATSIDE)

-DRY FLOODED FLOODED 10% ..._l00% 30 40 50 60 80 DR')

-FLOODED NUMBER OF PASNGERS:32 (ON LOWER BOATSIDE)

/

---

10%

lo 20

/4

27 .BOAT:9 0.67 NUMBER OF PASSENGERS: XIX .GRAPH.

DRY

-FLOODED FLOODED

31 (ON LOWER BOATSIDE) ____ 10%

_.100%

- -.

,,

60 50 60 7o 80 BOAT:15Ó.7

NUMBER OF PASSENGERS:51 (ON LOWER BOATSIDE)

- DRY GRAPH, XX - ,.-10% FLOODED FLOODED

//

/'

..._.. 100%

//'

/4

//

10

/

2Ó 30 40 5Ö 60 70

-.-30 E 25 20 = 15 -J e. c 10 Q z 5 o

5

10 15 20 25 25 E U 20 15 = 10 e. £5 Q z o

5

10 15 20 25 30

E D- 40 L, z 30 20 10 o ff25 L, z 20 15 10 5 BOAT K - 07 NUMBER OF PASSENGERS: GRAPH. xx:. 36 /( /1 DRY I FLOODED FLOODED

-10% _.._100% 0.67 NUMBER OF PASSENGERS: GRAPI-I. XXII 55 II -DRY FLOODED FLOODED

-10% ...._100% -10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80 w

Z 2 10 o o 10 20 30 15 5 20 30 40 50 60 70 29 BOAT: K - 0.67 NUMBER OF PASSENGERS: GRAPH. XXIII 73 DRY FLOODED FLÒODED

-10% _-_ 100%

A.

ALA

FA!N

_IA_i

_I

_I

r

BOAT: K - 067 -DRJ

_

NUMBER OF GRAPH. XXIV

PASSENGERS: 36 (ON LOWER BOATSIDE)

/

10% _-_100% FLOODED FLOODED

I

F,.

1/-

/

)

10 /20 J-,, -1 --- I 30 40 50 60 70 80

'-.-//

/./

7/

....

E o 40 e. z 2G

:

30 20 io 20 40 50 _y, BOAT: P - 0.67 NUMBER OF PASSENGERS: GRAPH. XXV 49 DRY

-FLOODED FLOODED 10% - - -100%

AAl

/?F4jI

I

BOAT: P - 0.67 NUMBER OF PASSENGERS:74 GRAPH. XXVI

-/

DR FLOODED FLOODED

-10%

-- l00°4

/

//

---io 20 3D 40

50 40 30 20 lo o 20 30 40 50 9, 31 BOAT: P - 0.67 NUMBER OF PASSENGERS: GRAPH. XXVII 99

/

DRY

-FLOODED FLOODED 1Ò% __100% .,.

"I

.,I :

4'

ó / A

f

_r

/

r

r

BOAT:P-0.67 NUMBER OF PASSENGERS: 49

(ON LOWER BOATSIDE) GRAPH. XXVIII

J,

/

J

, I

-50 0 30

30/

,//

DRY FLOODED FLOODED 10% - - _100% lo 20 30 40 50 70 80

L!UL

1% 1

Fig. 14 LIFEBOAT N 777-9-S

f IlL

---ii

I =8200 FULLNESS 0.67 I_1 8000 PASSENGERS 61 w =2800 DIMENSIONS IN MII H = 1150 L. 7940 L. = 80 L 8200 10 11 12 13 14 15 16 I6 19