[Paddlewise] Effect of beam

Maybe my memory is getting bad. I mentioned this in my book (first edition) 
The Shape of the Canoe as a theoretical observation.  Looking through my 
notes I seem to have gotten it from something I read by Havelock. Haven't 
read my book in years so did not twig to it right away that I even mentioned 
that. Anyway. I looked up some references and got this.

On page 54 of D.W. Taylor's Speed and Power of Ships 1933 edition. He refers 
to Havelock's experiments. Taylor says, "...it will be found that the 
increase in beam carried with it increased area of midship section. Had the 
beam been increased and draught decreased in proportion, the area of the 
midship section remaining unchanged, the results would have been different." 
He also says, "However, the variations of resistance with variations of the 
ratio of beam to draught are not very great as a rule." (Page 55)

He also says based  on testing of hulls based on the USS Yorktown that 
"..the broader and shallower the model the greater the resistance."

Principles of Naval Architecture elaborates on this in Volume II page 66 
where it discusses the net effect of increasing beam from the standpoint of 
wetted surface and speed of the vessel.

I also have a reference to tank tests done at the Delft Institute that 
suggest that the effect of variations of L/B and B/D ratios is small.

I think Larson and Eliason mention this in Principles of Yacht design but 
that may be a faulty memory. If needed I could dig that book out and check.

Obviously the effect of increasing beam depends upon whether you hold the 
displacement constant or the proportions constant.

Does that help?

Cheers

John Winters
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