CHIEF
Lab. V . Scli&spsbimkunde
Delft
H I S T O R Y OF T H E
N E T H E R L A N D S S H I P M O D E L B A S I N
D U R I N G T H E F I R S T 25 Y E A R S
B Y P R O F . D R . W . P. A . V A N L A M M E R E N DirectorLadies and Gentlemen!
I t is w i t h great pleasure that I comply w i t h the request made by the C h a i r m a n of tlie Board of Directors to give you a short historical review of the most i m p o r t a n t events that have taken place d u r i n g the 25 years' existence of o u r Ship M o d e l Basin and that have i n f l u e n c e d its development and g r o w t h . A f t e r g i v i n g this review 1 w i l l tell you about o u r plans f o r the f u t u r e development of the model basin.
Origin
A f t e r we had, on M a r c h 11th, 1932, successfully produced o u r f i r s t model f r o m its m o u l d — this model being that of a naval vessel — we hesitatingly proceeded, on about the 8th of A p r i l f o l l o w i n g , to carry o u t our f i r s t re-sistance tests. T h i s was a great event, i n w h i c h the whole staff, consisting of some ten men, assisted. W i t h our hearts beating, we noted d o w n the values f o u n d , h o p i n g that they w o u l d tally w i t h the results of the experiments that had been made w i t h this m o d e l i n the V i e n n a tank.
W h e n this agreement proved to be correct, and the results obtained w i t h a series of comparative tests w h i c h were carried o u t w i t h a second model, one of the — afterwards w e l l - k n o w n — ,,Simon B o l i v a r " series, were also satisfactory, the B o a r d of Directors decided to p u t the experiment tank o f f i c i a l l y i n t o use, n o t w i t h s t a n d i n g tlie fact that, o w i n g to the u n f a v o u r a b l e conditions, the chance of orders b e i n g o b t a i n e d must be considered to be rather n i l . I t was, therefore, decided to spend the next few months o n maki n g the personnel t h o r o u g h l y conversant w maki t h themakir tasks, on testmaking maki n s t r u -ments, o n a c q u i r i n g practice i n the m a n u f a c t u r e of various kinds of models of ships and propellers.
T h e i n a u g u r a t i o n took place on the 9 t h of May, 1932, about three years after the F o u n d a t i o n had been i n s t i t u t e d (28 June, 1929).
A t this m o m e n t the generosity shown by the Founders of the M o d e l Basin, the Steam N a v i g a t i o n Company , . N e d e r l a n d " L t d , the R o y a l Rot-terdam L l o y d L t d , the Royal Packet N a v i g a t i o n Company L t d , and the f o r m e r Netherlands Indies Tank-Steamer Company L t d may once more be g r a t e f u l l y recalled, a l l of w h i c h , together w i t h the Netherlands Government, placed at o u r disposal the f o u n d a t i o n capital, a m o u n t i n g to 700,000 guilders.
The Association of Supporters
O n tlie occasion of the i n a u g u r a t i o n of the N . S . M . B . the f i r s t present was made t h r o u g h the then C h a i r m a n of the Association of Supporters of the N . S . M . B . , w h i c h present consisted of an apparatus f o r measuring-propellers. W e are g r a t e f u l to be able to recall that i n the course of our existence we received many other u s e f u l presents f r o m that quarter.
I n subsequent years the support rendered by this Association was con-siderably extended. W h e n , i n 1947, the N . S . M . B . became self-supporting
1,6
-1935 1 9 4 0 1 9 4 5 1 9 5 0 1955
• YEAR
F i g . 2
f o r tire f i r s t t i m e , w i t h the exception of a single year before the second W o r l d W a r , i t was decided to suppress the guarantee f u n d i n w h i c h the N a t i o n a l C o u n c i l f o r I n d u s t r i a l Research T . N . O . o n the one hand, and the Netherlands S h i p p i n g Companies a n d Shipyards o n the other, partici-pated f o r 50 per cent each. D u r i n g the f i r s t f i v e years of o u r existence the a n n u a l guarantee c o n t r i b u t i o n s had been w i t h d r a w n to an average of a p p r o x i m a t e l y 70 per cent of the m a x i m u m a m o u n t promised of about 40,000 guilders a year.
A f t e r the suppression of the guarantee f u n d , f r o m w h i c h t i l l t h e n the deficiency o n the w o r k i n g c o u l d be covered, the t h e n c h a i r m a n of the B o a r d of Directors succeeded i n o b t a i n i n g , f o r the next ten years, the promise of c o n t r i b u t i o n s to the F u n d f o r Scientific Research, w h i c h had been created i n the m e a n t i m e , u p to an a m o u n t of 45,000 guilders a year. F r o m this f u n d the cost of free research w o r k was to be defrayed. T h i s success was due also to the great l i b e r a l i t y of s h i p p i n g and s h i p b u i l d i n g circles. T h e N a t i o n a l C o u n c i l T . N . O . was f o u n d w i l l i n g to p r o v i d e f o r this purpose an equal a m o u n t f r o m the G o v e r n m e n t resources. I n a d d i t i o n , an a n n u a l subsidy of 10,000 guilders was, f r o m this date, granted by the Association of Netherlands S h i p b u i l d i n g Industries. T h i s a m o u n t was sup-p l e m e n t e d by the N a t i o n a l C o u n c i l T . N . O . by an equal sum. Hence 110,000 guilders were available f o r Scientific Research annually.
I n view of this new organization f o r Scientific Research, i n w h i c h F o u n -ders of a n d C o n t r i b u t o r s to the o r i g i n a l guarantee f u n d participated, the Association of Supporters decided to undertake, i n c o n j u n c t i o n w i t h T . N . O . , the task of m e e t i n g any deficiencies o n the w o r k i n g of the N . S . M . B . i n the f u t u r e .
T h e liappy circumstance that so far there had been no need of malcing use of this support, i n d u c e d the Board of this Association i n 1955 to partici-pate i n the F u n d f o r Scientific Research w i t h 5,000 guilders yearly. W h e n , i n 1956, the c o n t r i b u t o r s to the F u n d decided to double their c o n t r i b u t i o n s , the Board foUo^ved this example. T h e F u n d f o r Scientific Research now has the disposal of 230,000 guilders i n c o n t r i b u t i o n s per year.
Progress made
C o n t r a r y to expectations, sixteen commissions, a m o r n i t i n g to a p p r o x i -mately 25,000 guilders, c o u l d be booked i n the course of 1932, w h i c h proved at once that even i n those adverse times, o u r M o d e l Basin supplied a certain need.
W i t h j o i n t strenuous efforts the i n n u m e r a b l e d i f f i c u l t i e s experienced i n the f i r s t few years were overcome. W i t h the increasing experieirce gained i n the tank and i n the workshops and by overcoming the inevitable teething troubles w i t h the appai-atus used, the costs of m a n u f a c t u r i n g ship and propeller models as w e l l as the terms of delivery c o u l d be gradually reduced, so that every reasonable r e q u i r e m e n t i n this matter c o u l d be met.
T h e graphs of the n u m b e r of ship models made a n n u a l l y and of the receipts and e x p e n d i t u r e -svill give you a clear p i c t u r e of the increasing confidence that Owners and Shipbuilders are e x t e n d i n g to the M o d e l Basin. N a t u r a l l y , the economic s i t u a t i o n and the second W o r l d W a r had a great i n f l u e n c e o n the course of the operations, b u t there is a distinctly perceptible g r o w t h , p a r t i c u l a r l y i n the post-war years. I t is estimated that i n 1957 the receipts will a m o u n t to P / i m i l l i o n guilders.
T h e staff employed was steadily increasing. A strong increase has been perceptible since the f o u n d a t i o n of the Scientific-Research Department. T h i s department, ivhich, as has been said, is beiirg f i n a n c e d f r o m the F u n d f o r Scientific Research, now comprises 21 persons, who, under the d i r e c t i o n of D r J. D . van Mairen, apply themselves to c a r r y i n g o u t free research w o r k . I must i m m e d i a t e l y add, however, that f o r the present this depart-ment is also charged w i t h w o r k connected w i t h commissions f o r the Seakeeping Basin.
T h e staff n o w comprises 117 persons, i n c l u d i n g 7 naval architects and 7 T e c h n i c a l School-graduates. T h e percentage of naval architects and T e c h n i c a l School-graduates is small compared w i t h those engaged w i t h sister i n s t i t u t i o n s abroad. I presume that this phenoinenon must be at-t r i b u at-t e d at-to at-the facat-t at-thaat-t at-the operaat-tions w i at-t h at-the N . S . M . B . are sat-trongly sub-d i v i sub-d e sub-d ansub-d are p e r f o r m e sub-d by specializesub-d employees. T h i s makes i t pos-sible to charge lower-grade engineers h a v i n g a f a i r a m o u n t of c o m m o n sense, i n the l o n g r u n w i t h w o r k that can i n i t i a l l y be done by higher-grade employees only. I n the Wageningeir T a n k the w o r k on the t o w i n g carriage, f o r instance, is successfully done by y o u n g m e n who have been t r a i n e d as i n s t r u m e n t makers.
Extensions
Passing by soine m i n o r i n t e r i o r r e b u i l d i n g s that took place i n 1935, we may m e n t i o n that i n 1938 the f i r s t extension of the M o d e l Basin was completed. W e t h e n got the disposal of a d r a u g h t i n g r o o m f o r scientific
160
160
1935 1940 1945 1950 1955
—YEAR
F i g . 3
w o r k , a conference r o o m , t w o w o r k r o o m s , and a lecture r o o m w i t h a recep-t i o n aparrecep-tmenrecep-t. A recep-t recep-the same recep-t i m e recep-the insrecep-trumenrecep-t-makers shop was enlarged.
T h e c o n s t r u c t i o n of a c a v i t a t i o n t u n n e l w h i c h was begun at the same t i m e , was n o t completed u n t i l 1942, o w i n g to the w o r l d war. T h e re-m a i n i n g years of war were u t i l i z e d f o r c a r r y i n g o u t experire-ments w i t h this i m p o r t a n t i n s t r u m e n t , so that, after the t e r m i n a t i o n of the war, we were ready p r o m p t l y f o r dealing w i t h the commissions i n hand. Simultaneously w i t h the c a v i t a t i o n - t u n n e l b u i l d i n g a f o u n d r y f o r casting bronze propellers was b u i l t a n d installed. T h e fact may be recalled that the money r e q u i r e d f o r the b u i l d i n g , a m o u n t i n g to 216,000 guilders, was placed at our disposal by the G o v e r n m e n t , the P u b l i c W o r k F u n d 1934, a n u m b e r of large ship-p i n g comship-panies, some ship-private ship-persons, and the M o d e l Basin. For the f i r s t f e w years of operations a considerable guaranteed a m o u n t was placed at o u r disposal by a c o m b i n a t i o n of the p r i n c i p a l shipyards and engineering works i n this c o u n t r y .
I n 1951 the l e n g t h e n i n g of the large m o d e l basin by 92 m . as well as an enlargement of offices a n d workships was completed. T h e lengthening of the basin s u p p l i e d a great need, p a r t i c u l a r l y i n view of the testing of models of fast ships f o r the R o y a l Navy. As a result of increasing the l e n g t h of the measuring section a n u m b e r of experiments, among others the open-water screw tests, c o u l d be c a r r i e d o u t i n less t i m e , w h i l e the accuracy of the measurements could, i n general, also be increased. By enlarging the o f f i c e b u i l d i n g the e x i s t i n g s u b d i v i s i o n of the d r a w i n g office c o u l d be done away w i t h , w h i c h had an appreciable i n f l u e n c e o n its efficiency. T h i s can also be said of the completed extension of the instrument-makers shop. T h i s t i m e the costs r e s u l t i n g f r o m the l e n g t h e n i n g of the m o d e l basin were f i n a n c e d w i t h the a i d of the loans made b y the G o v e r n m e n t .
F i g . 4. A survey o f the facilities o f the N . S . M . B .
w i t h f l o w regulator, w h i c h enabled screws to be examined w i t h regard to their cavitation properties i n fields -which correspond entirely w i t h those o c c u r r i n g b e h i i r d the ship or irrodel. T h e a d o p t i o n of this new f a c i l i t y i n the course of 1956 meant a l o n g stride i n measuring the cavitatioir of screws. T h e i-notive leadiirg to this extension was to create a better agreement between the conditioirs under w h i c h the experimeirts were made and those under w h i c h the ship is r u i m i n g .
T h e same m o t i v e l e d to the construction of the Seakeepiirg L a b o r a t o r y , w h i c h was completed i n the same year. I n this laboratory also the actual conditions of the ship can be i m i t a t e d m u c h better than i n the tank w i t h stationary water, especially now that i t has become possible to generate waves of any l e n g t h and height i n any d i r e c t i o n desired and, i f r e q u i r e d , to m i x waves of d i f f e r e n t lengths and heights.
Since the i n a u g u r a t i o n by H . R . H . Prince B e r n h a r d on the 2 n d of M a y , 1956, considerable progress has been made i n the development of the apparatus. A t present the models are r u n by means of automatic steering gear. Recently, i t has become possible to carry out a n t i - r o l l i n g tests i n waves w i t h models p r o v i d e d w i t h a n t i - r o l l i n g fins, governed electronically ac-c o r d i n g to various systems. D u r i n g this symposium a model of a V i ac-c t o r y ship, p r o v i d e d w i t h activated stabilizing fins, w i l l be demonstrated to you.
I n f i n a n c i n g the Seakeeping L a b o r a t o r y considerable support was once more received f r o m the N a t i o n a l C o u n c i l T . N . O . , the S h i p p i n g Compairies and Shipyards to the a m o u n t of 400,000 guilders each. T h e remainder, a m o u n t i n g to 800,000 guilders, as w e l l as the a m o u n t of 175,000 guilders needed f o r the irew c a v i t a t i o n t u n n e l , were p a i d o u t of o u r o w n resources. T h e latest extension, w h i c h was p u t i n t o service a few months ago, com-prises new workshops, a large d r a w i n g office f o r 50 employees, and a model h a r b o u r f o r keeping most of the models, a p p r o x i m a t e l y 80 i n n u m b e r , w h i c h
are b e i n g used a n d were f o r m e r l y l y i n g i n the large m o d e l basin and reduced its effective l e n g t h by about 80 metres. N o w that these models have beeir re-m o v e d f r o re-m the t o w i n g tank, we shall be able to use the re-m o d e l basin w i t h greater efficiency.
T h e cost of this extension, a m o u n t i n g to 700,000 guilders, was f i n a n c e d out of o u r o w n resources. I n e n a b l i n g this to be done, however, considerable s u p p o r t was received i n the f o r m of t r a n s i t i o n payment of the said a m o u n t b e i n g g r a n t e d us by a f e w s h i p p i n g companies and shipyards f o r a p e r i o d of two years.
A t the risk of b e c o m i n g l o n g - w i n d e d I must f u r t h e r tell y o u something of a recent extension of o u r facilities w h i c h is n o w i n course of preparation, viz. the l a b o r a t o r y f o r i n l a n d s h i p p i n g . T h i s basin, measuring 217 by 15.75 by 1.20 m , w i l l be f i t f o r testing models of r i v e r and canal vessels and of barge fleets. F r o m various quarters a keen interest has been shown i n the construc-t i o n of construc-this basin, xvhich inconstruc-teresconstruc-t is b e i n g demonsconstruc-traconstruc-ted by construc-the b i n d i n g promises made by a n u m b e r of large shipyards and s h i p p i n g companies f o r large t o w i n g programmes to be carried o u t d u r i n g the n e x t f i v e years.
W i t h deep g r a t i t u d e we must again make m e n t i o n of the support we received f r o m G o v e r n m e n t and i n d u s t r i a l circles i n the c o n s t r u c t i o n of this new basin. T h e Association of Netherlands S h i p b u i l d i n g Industries has given a d o n a t i o n of 250,000 guilders. T h e R o y a l Netherlands Shipowners' Association w i l l co-operate this t i m e by way of a l o a n o n terms favourable as regards interest and r e d e m p t i o n . T h e t o t a l cost w i l l a m o u n t to L / a m i l l i o n guilders.
Ladies a n d gentlemen, thus far I have given a summary of the extensions to the N . S . M . B . I s h o u l d n o w l i k e to c o n t i n u e r e l a t i n g its history and f o r a m o m e n t d w e l l u p o n a less f o r t u n a t e p e r i o d of the N . S . M . B .
The War Period
T h e h o p e f u l expectations raised by the large n u m b e r of commissions that were received d u r i n g the f i r s t eight months of 1939 were dashed by the o u t b r e a k of the war. A l t h o u g h the f i n a n c i a l results of that year were n o t u n f a v o u r a b l e — the N . S . M . B . had become self-supporting f o r the f i r s t t i m e since its b e i n g p u t i n t o service — the c o m i n g events already cast t h e i r shadows before. O n M a y 10th, 1940, the f i r s t evacuation of the W a g e n i n g e n m u n i c i p a l i t y t o o k place, and the premises of the M o d e l Basin had to be abandoned. T h i s abandonment, however, was of short d u r a t i o n , and on our r e t u r n i t was f o u n d that l i t t l e damage had been done. F r o m the graph shown i t w i l l appear what d e t r i m e n t a l consequences the war had o n the r u n n i n g of the m o d e l basin. Drastic economies consisting i n the r e d u c t i o n of w o r k i n g hours and an even larger r e d u c t i o n of wages and salaries d i d n o t counterbalance the decline i n the revenues. L a c k of com-missions c o m p e l l e d us at f i r s t to look o u t f o r other activities. A l o n g t i m e was spent i n a u s e f u l and, at the same t i m e , healthy manner o n f e l l i n g beech trees w h i c h had been damaged o w i n g to the w a r l i k e operations and on sawing t h e m i n t o generator blocks, i n w h i c h sport a n u m b e r of o u r people achieved remarkable d e x t e r i t y . A f e w other members of the staff occupied themselves w i t h w r i t i n g a book o n „ R e s i s t a n c e and P r o p u l s i o n of Ships", w h i c h was p u b l i s h e d i n 1942 and received m u c h appreciative
com-F i g . 5. S l i a l l o w w a t e r basin u n d e r c o n s t r u c t i o n
ment. A f t e r the war this book was translated i n t o various languages, w h i c h has u n d o u b t e d l y consolidated the g o o d w i l l of o u r M o d e l Basin abroad. T h e enrployees of the dra^ving office busied themselves i v i t h d r a w i n g u p statistics i n w h i c h the results of a l l resistance tests ivere digested. These statistics subsequently f o r m e d the basis f o r numerous proposals to i m p r o v e the h u l l forms sent i n and thus also c o n t r i b u t e d to establishing and strength-ening tlie r e p u t a t i o n of o u r M o d e l Basin to a considerable degree.
A k h o u g h , i n the f o l l o w i n g years of war, the activities of the N . S . M . B . still received a severe setback f r o i r i the a b n o r m a l circumstances, they grad-ually increased again u n t i l i n the early part of 1944, w h i c h was due to an increase i n the orders w h i c h ivere received f r o m the Netherlands, France and D e n m a r k i n connection w i t h the f u t u r e r e b u i l d i n g of the fleet, b o t h of seagoing vessels, i n c l u d i n g f i s h i n g vessels, and of i n l a n d craft.
As i n many other branches of industry, the years 1944-1945 and 1946 f o r m p a r d y black, p a r t l y grey pages i n the history of the N . S . M . B . O w i n g to the second evacuation, w h i c h took place on October 1st, 1944, the sub-sequent w a r l i k e operations and destructions to the M o d e l Basin, activities ^vere g o i n g on f o r o n l y l i t t l e more than 8 months d u r i n g the years 1944 and 1946, ivhile n o t h i n g at a l l was done i n 1945. I t was also due to the assistance rendered by the Royal Navy and by various sister i n s t i t u t i o n s b e l o n g i n g to the I n d u s t r i a l Research C o u n c i l T . N . O . that ive got the disposal of a s u f f i c i e n t a m o u n t of implements, machines, f u r n i t u r e and d r a w i n g requisites w h i c h enabled operations to be gradually started again i n M a r c h 1946 and w o r k to be resumed at f u l l capacity i n the early p a r t of May, 1946. T h e cavitation tunnel was n o t completed u n t i l the end of 1946.
A f t e r ttie w a r years p r o d u c t i o n c o u l d soon be raised to the level of the busiest pre-war years. O n M a y 1st, 1952, hence 20 years after the inaugura-t i o n of inaugura-the N . S . M . B . , inaugura-the one-inaugura-thousandinaugura-th ship m o d e l c o u l d , w i inaugura-t h some ceremony, be launched, w h i l e at the m o m e n t , i.e. about 5 years later, m o d e l N o . 1700 is afloat.
T h e years f o l l o w i n g 1947 show a constantly increasing w o r k i n g result, w h i c h has enabled us to finance large portions of the new facilities.
Scientific Research
At one of the f i r s t meetings of the Advisory C o m m i t t e e of the B o a r d
of D i r e c t o r s already, the Sub-Committee f o r Scientific Research was called i n t o existence, w h i c h started operations i n the scientific f i e l d assigned to o u r M o d e l Basin.
U n d e r the d i r e c t i o n of the late Prof. Vossnack a n d his successor. Prof. J. W . Bonebakker, m u c h scientific research has been carried out. Before the N . S . M . B . , i n 1942, got special f u n d s at t h e i r disposal, this w o r k had to be done at t h e i r o w n expense, and at first, i n view of the l i m i t e d n u m b e r of the staff, f o r the greater p a r t o u t of the o r d i n a r y w o r k i n g hours. Oc-casionally, i n d i v i d u a l amounts were p a i d f o r this purpose by the Association of Supporters, the N a t i o n a l C o u n c i l f o r I n d u s t r i a l Research T . N . O . and the N e t h e r l a n d s Association f o r I n l a n d W a t e r Services. These moneys were destined f o r an investigation i n t o the shape and p r o p u l s i o n of vessels f o r i n l a n d n a v i g a t i o n . I n this case the investigations l e d to a saving of 50 per cent, i n engine power as compared w i t h the machinery installed i n the ship type t h a t was then i n use. A result that can be effectively used i n con-10
v i n c i n g doubters of the usefuhiess of resistance tests on subsequent oc-casions!
I t w o u l d lead nre too far a f i e l d i f I were to give you, at this moment, a survey of the research w o r k that has been done d u r i n g the 25 years of o u r existence. T h e results are to be f o u n d i n the, a p p r o x i m a t e l y , 140 publica-tions u'hich have h i t h e r t o appeared at home and abroad, w r i t t e n by various members of o u r staff. O f late, a l l publications have been p r i n t e d i n the English language to render them accessible to o u r f o r e i g n relations.
I t nray suffice to m e n t i o n a few i m p o r t a n t programmes ivhich have been carried o u t i n the course of o u r existance. T h e progranrme concerning vessels f o r i n l a i r d navigation has already been meirtioned. F r o m the same t i m e dates the systeinatic research i n t o the h u l l forms of small seagoing cargo ships. I t was f o l l o w e d by the programme concerning the systematic screw series. T h e results of the ,,S. B o l i v a r " programme have largely coir-t r i b u coir-t e d coir-to clearing our knowledge of scale effeccoir-t i n coir-the compoirencoir-ts of propulsive efficiency of single-screw cargo ships. T h i s may also be said of the tests subsequently carried out w i t h a large m o d e l f a m i l y of the V i c t o r y ship type, i n c l u d i n g the tests made w i t h the m o d e l boat „ D . C. E n d e r t Jr", constructed to a scale of 1 : 6, i n the waters along the C r o a t i a n coast.
T h e e v o l u t i o n of the vortex theory f o r designing non-cavitating ship propellers, as w e l l as the e x t r a p o l a t i o n p r o b l e m , w h i c h comes u p f o r con-sideration i n calculating ship resistance, constantly had our f u l l a t t e n t i o n . T h e latter p r o b l e m was, f o r instance, t h o r o u g h l y studied w i t h the a i d of results obtained f r o m experiments w i t h a m o d e l f a m i l y of the R h i n e tanker „ A r a b i a " and the full-size ship. Considerable improvements were obtained i n the f i e l d of irozzles, aird thoughts are n o w r u n n i n g t h r o u g h our minds that irozzles may, i n f u t u r e , be applied to seagoing vessels as w e l l .
F i g . 8. C a v i t a t i o n p a t t e r n o f a tanlcer screw i n a n u n e q u a l v e l o c i t y field
Contacts at home and abroad
T l i e d a i l y contacts w i t h o u r customers at home and abroad have natu-r a l l y venatu-ry lanatu-rgely c o n t natu-r i b u t e d to the development of o u natu-r knowledge. F natu-r o m the b e g i n n i n g m u c h value has been attached to these contacts because we were convinced that the best results c o u l d be obtained i f theory and practice were g o i n g h a n d i n hand. T h e r e f o r e , the customers were encouraged at any rate to attend the most i m p o r t a n t tests and to discuss the results. T h i s has the a d d i t i o n a l advantage that the p r o v i s i o n a l results are taken home o n the very day that the experiments are made and that arrangements can be made w i t h regard to possible proposals f o r m a k i n g improvements.
A p a r t f r o m these daily contacts, the contacts p e r i o d i c a l l y r e c u r r i n g via the A d v i s o r y C o m m i t t e e a n d the Sub-committee i o r Scientific Research must be m e n t i o n e d . O f recent date are the s t i l l more direct contacts w h i c h the N . S . M . B . has made w i t h practical m e n by means of the Groups of W o r k e r s i n the f i e l d of research o n seakeeping and cavitation-erosion. These groups of workers, whose object i t is to stimulate the Scientific Research i n the said fields a n d co-ordinate i t w i t h the practical needs f i l l a real need.
O w i n g to professors of tire Sub-department of N a v a l A r c h i t e c t u r e of the T e c h n i c a l U n i v e r s i t y at D e l f t being members of the Board of Directors, A d v i s o r y C o m m i t t e e , Sub-Committee f o r Scientific Research, and Groups of W o r k e r s , proper contact was made w i t h the T e c h n i c a l U n i v e r s i t y at D e l f t as early as the establishment of the F o u i r d a t i o n . T h i s contact was con-solidated by the a p p o i n t m e n t , i n 1946, of the D i r e c t o r as a professor e x t r a o r d i n a r i u s of the said T e c h n o l o g i c a l U n i v e r s i t y . A t the departm-e of the f o r m e r superintendent, the latter's f u n c t i o n passed to his successor.
F r o m 1936 on-ward there has been close co-operation between the N . S . M . B . a n d this U n i v e r s i t y w i t h regard to model experiments. I n that year the N . S . M . B . leirt finaircial assistance to arrive at the construction of a sirrall experiment tank at D e l f t . A f t e r the m o d e r n ship model basin of the Sub-department, w h i c h , o w i n g to its coirsiderably larger size and superior apparatus, offers many more possibilities f o r research than the earlier laboratory, had been completed, scientific research i n b o t h establish-inents was co-ordinated. A n aniinated co-operation started, w h i c h was re-vealed by periodically r e c u r r i n g meetings betiveen members of the staffs of b o t h model-experiment tanks, d u r i n g w h i c h experiences were exchanged and the c u r r e n t programmes discussed.
A n o t h e r i m p o r t a n t contact is that made w i t h the Research Centre T . N . O . f o r S h i p b u i l d i n g and N a v i g a t i o n , w h i c h came i n t o being i n 1947, at the i n s t i g a t i o n of the f o r m e r superintendent of the N . S . M . B .
Iir the early part of our existence already a h i g h value was attached to i n t e r n a t i o n a l contact i n the scientific f i e l d . N a t u r a l l y , the N . S . M . B . , then s t i l l b e i n g a novice, c o u l d learn a great deal f r o m the various sister i n s t i t u -tions abroad, w h i c h had been f o u n d e d l o n g before. T h e N . S . M . B . has entered i n t o numerous relations i v i t h these i n s t i t u t i o n s , and some members of the staff received their f i r s t t r a i n i n g at f o r e i g n i n s t i t u t i o n s , such as at H a m b u r g and V i e n n a .
I n many cases these relations have developed i n t o personal bonds of f r i e n d -ship between leaders and members of the staffs, w h i c h has been very b e n e f i c i a l to t h e i r co-operation. I n later years, the N . S . M . B . has, i n its t u r n , become the nursery of a n u m b e r of new f o r e i g n sister i n s t i t u t i o n s and has designed and m a n u f a c t u r e d their apparatus. I t has extended hospitality to many f o r e i g n scientific workers f o r shorter or longer periods of time.
T h e I n t e r n a t i o n a l T o w i n g T a n k Conferences w l i i c h are h e l d at regular intervals, and the f i r s t of w h i c h was h e l d at the Hague i n J u l y , 1933, o n the i n i t i a t i v e of Prof. T r o o s t , have largely c o n t r i b u t e d to this good relationship.
P a r t i c u l a r l y after the war the f o r e i g n contacts have considerably extended. T h e i m p r o v e m e n t of the transport facilities has made i t possible to attend, w i t h o u t much loss of time, meetings h e l d by institutes abroad and to read papers o n these occasions.
I n 1951 the f o r m e r superintendent accepted the f l a t t e r i n g i n v i t a t i o n to give lectures at M . I . T . i n Bostoir and at the Berkeley U n i v e r s i t y of Califor-n i a f o r oCalifor-ne year. A year later he was most h o Califor-n o u r a b l y dismissed i Califor-n coCalifor-nCalifor-nec- connec-t i o n w i connec-t h his enconnec-tering u p o n his new duconnec-ties as H e a d of connec-the D e p a r connec-t m e n connec-t of N a v a l A r c h i t e c t u r e and M a r i n e E n g i n e e r i n g at M . I . T . i n Boston.
W e are m u c h pleased to see Prof. T r o o s t among us at the celebration of the 2 5 t h anniversary of the f o u n d a t i o n of our N . S . M . B . , w h i c h he served to the best of his a b i l i t y f o r more than 20 years.
F i g . 9. W a v e g e n e r a t o r p r o d u c i n g o b l i q u e waves
The Present and the Future
Ladies a n d gentlemen, a j u b i l e e always affords one a suitable o p p o r t u n i t y of casting a glance at the events i n the past. I t has become a custom and, i n some respects, a good custom, because an analysis of the events w h i c h happened i n the past may assist us i n d e t e r m i n i n g the course we have to take i n the f u t u r e . I t may also save us f r o m errors that were c o m m i t t e d i n the past.
H o w e v e r , preference of the f u t u r e to the past is i n h e r e n t to h u m a n nature. A l l o w me, therefore, to give, a f t e r this retrospect of the past, a l i t t l e consideration to the f u t u r e .
I f we ask ourselves w h a t the present s i t u a t i o n is of ship m o d e l research i n general and that of the N . S . M . B . i n p a r t i c u l a r , and i n d o i n g so, also question i n w h a t d i r e c t i o n this i n v e s t i g a t i o n is p r o b a b l y going to move i n the near f u t u r e , the answer m i g h t be summarized as f o l l o w s :
1. T h e qualities of the ship f o r m and p r o p e l l e r have, as regards hydro-d y n a m i c shaping, been i m p r o v e hydro-d by a p p r o x i m a t e l y 25 per cent, i n the last 25 years.
2. T h e investigations iir to stationary phenomena w i t h ship m o d e l and p r o p e l l e r , i.e. the testing of propellers i n a homogeneous velocity f i e l d , of ship models i n currentless, deep water of considerable breadth, have entered u p o n a phase i n w h i c h spectacular improvements of t h e i r q u a l i t i e s can no longer be expected..
M o d e l tests c o n t i n u e to be necessary, however, f o r ensuring these q u a l i t i e s i n i n c i d e n t a l cases, p a r t i c u l a r l y i n view of the constantly vary-i n g demands w h vary-i c h are b e vary-i n g made b y the owners f o r t h e vary-i r shvary-ips. I t must
be considered impossible diat the construction of standard ships i n a large way w i l l be a r r i v e d at, n o t even i n the case of tankers, w h i c h are very w e l l adapted i n this respect. A m o n g ships of this type there is a great variety, and t h e i r development is i n constant progress.
Very interesting i n this respect is the table p u b l i s h e d by Davidson *) i n 1954, i n w h i c h the ,,transport m o m e n t u m " , i.e. the p r o d u c t of the ship speed i n knots and the displacement i n tons, is compared w i t h regard to ship types f r o m the Greek s a i l i n g vessel of 1000 B.C. to the l i n e r „ U n i t e d States". T h e transport m o m e n t u m has increased f r o m 50 f o r this sailing vessel to 1,500,000 f o r the , , U n i t e d States", w h i c h was designed i n 1950. A supertanker h a v i n g a displacement of 50,000 tons and a speed of 20 knots has a m o m e n t u m of 1,000,000 knots x tons. T h e m a x i m u m transport m o m e n t u m given i n Davidson's table has meanwhile been surpassed by that of the m a m m o t h tankers. A feiv weeks ago the N . S . V L B . received an order f o r testing a similar tanker having a displacement of 136,000 tons at a speed of 15 k n . H e r transport m o m e n t u m , therefore, a m o u n t e d to 2,000,000 knots x tons.
Speed knots Displacement tons
Transport Momentum Tons X kts. Sail (wood) 1000 B . C . Greek . . . . 1 50 50 1000 A . D . V i k i n g . . . . 3 60 180 1492 „ S a n t a M a r i a " . . . 3-V. 80 280 1850 „ J a m e s Raines" . , 7 2500 17500 Power (steel) 1850 „ G r e a t E a s t e r n " . . 11 27000 300000 1950 M a r i n e r 20 20000 400000 1950 S u p e r T a n k e r . . . 20 50000 1000000 1950 „ U n i t e d States" . . 30 50000 1500000 1957 M a m m o t i i T a n k e r . 15 136000 2000000
H i s t o r y o f sliip speeds a n d sizes.
T h i s development w i l l , also w i t h regard to the investigation i n t o stationary phenomena, c o n t i n u e to make its demands on e x p e r i m e n t tanks.
3. T h e e m p l o y m e n t of special structures, such as nozzles, may lead to f u r t h e r improvements of the q u a l i t y , w o r t h w h i l e considering.
4. V l u c h a t t e n t i o n w i l l , i n f u t u r e , have to be p a i d to the p r o b l e m of d e t e r m i n i n g the o p t i m u m shape of i n l a n d craft. I t is presumed that the qualities of ship f o r m and p r o p u l s i o n can s t i l l be considerably i m p r o v e d . 5. T h e t r a n s i t i o n to the investigation i n t o non-stationary phenomena, i.e.
the testing of screws i n an u n e q u a l velocity f i e l d , and that of ship models i n o b l i q u e waves opens u p great possibilities. Personally, I am of o p i n i o n that i n this connection research has entered u p o n q u i t e a new phase and that we are o n the eve of a fresh development i n this f i e l d , w h i c h may i n v o l v e many surprises.
*) K . S . M . D a v i d s o n , W h a t p r i c e speed? L o n g - r a n g e trends i n overseas t r a n s p o r t a t i o n ; B u l l e t i n Febr. 1955, S N A & M E .
