Thank you both for responding. Again, if you can remember the exact articles or references, please send.
Now, just for reference, I''m starting this discussion because I''m tired of the constant yelling to "Get off the bow!!". I feel like this perception of keeping weight off the bow, altogether and in any conditons, seems to be standard, little understood, rhetoric. People just say it/do it, "because everybody does it."
Now, too your reponses.
Point number 1. Weight on the bow causes the bow to sink-True. It follows that this would increase the width of the boat''s entry profile through the water, thereby slowing the boat during the moments that it passes through/over waves or wakes. Is this maybe an assumption? One would truly have to look carefully at the footprint of the boat''s
lines at water contact to determine this. Designers mostly look for the average footprint/bootstripe to get the best performance under standard copnditons. It is certainly not the best under all conditions.
Would the entry profile actually widen by such a degree as to see a measurable effect on performance an all boats in all conditions? I don''t know. I don''t believe so. I do recall having read an article (sorry, no recollection on the reference) which was discussing the measurable increase in performance by keeping the water flow across the hull as stable as possible. In fact the article''s statistics seemed to imply that, on average, the flow''s stabilty of water over the hull could affect boat speed by as much as 20%, in some casses. Hence, the all important aspect of a clean smooth bottom. (How much do we spend on
paint and weekly/monthly scrubbing?)
So, where I race, San Diego bay, we contend with wavelets (from wind) and the occasional ships wake. Its my experience that keeping the boat level and passing through the small waves (6 to 12 inches), as opposed to going over (allowing the boat to follow its own path up and over) may decrease my speed intitially but allows for increased acceleration and cruising speed more quickly after the wave. Is this due to a more stable flow over the hull? Again, I don''t know. It seems logical. Just as a deeper bow profile seems logical in decreasing my spped.
Point number 2. Spreading crew weight across the boat (instead of centered) can cause pitching. Its key that we have to consider the conditions. In light air (< 10 knots), low wave/swell action conditions, pitching will not occur. (Our situation 85% of the time here in San Diego) If there were pitching I can certainly see how that could drastically affect the flow of air over the sails. (i.e. cause instability in the wind''s flow over the sails).
But, does the pitching motion really increase with say 10% of crew weight moved to the bow? It seems so. The bow goes off waves at a steeper angle with the boats stern going higher over the wave. But at the same time the bow plows shallower through the wave while the stern stays more level at the begining. Maybe the pitching does not increase but, just seems as such. I don''t know without more experience. But, sometimes it doesn''t really seem so.
Minor Point in your responses. Bow down with stern out reduces water
line length. Again, this may be significant on some boats, depends on the design. On my brother''s Ranger 26 has pretty steep flare at the bow. Keeping the stern down and pushing the bow down 1 inch actually increases LOW by 1.5 inches. But, on say an ID 35 where the bow is nearly vertical...no change.
Length on the water
line though, is only a significant determinant when the boat is actually approaching or at hull speed. Not a common occurance around here. On our Summer Beer Can Series we regularly place first in our class (out of 14) with an average speed of 2-3 knots.
Anyway, all just a bunch of rambling. More opinions the better. I''m certainly interested in more feedback. What I do know is that I am going to spend some time testing various combinations of crew weight-particularly in light wind conditions, against pointing ability and speed/acceleration.
Thnaks again.