October 24th, 2014

Hi,
This is my first posting on this site.

I was made aware of it by a colleague.

Interesting take/s on the effect of chines.

My first chined boat is the one in the photo in the Seattle news letter which Eric has referred to.I was asked to write a few lines re the effect of chines on an IOM R/C yacht. In brief I stated that what I saw was a reduced hull size, especially on the windward side.Reduced mass and what I regard as a useful function in providing "grip" on the leeward side.
This last function drew a contrary opinion from an unnamed source who stated that it served no such purpose.

I do not have letters after my name relating to boat design, but having sailed for longer than I like to remember and gathering information and designing what could be referred to as successful R/C boats, I think I have some idea of what happens to a hull when sailing.
After seeing chined R/C hulls and how they handled, especially in stronger winds, I decided to try my hand at designing one.

The result was a boat named Cheinz that performed very well "straight out of the box" at the 2011 IOM Worlds.
I still say that chines have an effect on minimizing leeward drift.Don't have to be a scientist. Take a piece of plywood and drag it sideways through the water at say 45 deg to the direction of drag. Now do it at 90 deg. Which produces the most resistance?.The chines angle the topsides to give a less angled "bite" to the water.
All the discussion about "lift" to windward from foils does not gel with me. I think they minimize slip to leeward.After all they are not like plane wings. They are uniform on both sides!. Some are better than others!.

If you can add "grip" from another source,(chines), it can only be beneficial as long as the chines do not have detrimental effects to cancel out the benefits.
Have yet to find out if there are detrimental effects so far and have tried the chines out on a 10 rater and a just launched Marblehead (Won 29 of 34 races in it's first event).This boat also has a reverse bow. On first tryout this also seemed to do the job. In one race (over rigged), it powered downwind with the bow depressed but not right under and still steered dead straight. Very encouraging!.

Still have things to try, but for me chines work. Don't fully understand why and don't have the training etc to try and explain. Sometimes ignorance is bliss. Ask a hummingbird!.

By the way, have discussed this subject with another R/C boat designer. First of the modern era to use chines and also another who designs big boats and both agree that chines provide resistance to leeward drift.