Main reasons are that it is harder to build a canting rotating rig as the bearings have to be angled, and the gains are not large at small angles of cant or rake, or particularly necessary as the bow down trim is pretty minimal. However, the main reason is safety. If you fly a hull, the force on the sail increases as the boat comes heels, which makes it fly higher. If you do capsize, the weight of the windward hull at more than 90 degrees might sink the mast, making recovery much harder.
The German Solitarry has an oversize top bearing with the mast on one side and a ball at the bottom. This means the mast is always raked forwards relative to the axis of rotation, which reduces the sheeting loads. Also means it can be canted to leeward to help right it if it should capsize.
If I was to build a cantable mast, it would be a large version of a windsurfer mast, attached to a stub mast with a universal join (probably a length of rope). 2 or 3 lines at the base would control the position of the foot of the mast and hence the rake and cant. Also very easy and safe to drop it if required.
On Sat, Mar 21, 2015 at 1:37 AM, Gardner Pomper gardner@networknow.org [harryproa] <harryproa@yahoogroups.com.au> wrote:
In the diesel electric thread that is going on, there is some mention of harryproas running slightly bow down under sail, and how a schooner rig might help.This made me wonder why the harryproa masts are not canted slightly. It would seem that a 10 degree cant to windward would provide some lift and would also make the lw hull structure a bit stronger.I am thinking that it helps structurally since it would provide more lw area at the deck and more ww area at the base, which are the two highly stressed areas under load.So why aren't the harry masts canted? Does this lose too much sailing performance in other ways?- Gardner
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Posted by: Rob Denney <harryproa@gmail.com>
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