Boat Performance Change With Foil Rudder.

[capt_nemo]

Haven't yet read a Post that provides information needed to make an informed decision whether or not to change the rudder on my SunCat to a Foil.

It would be greatly appreciated if someone would clearly specify, describe in detail, or better yet, actually quantify the change in boat performance as a result of a change to a Foil Rudder.

Thank you.

[Tom Ray]

I have not seen any numbers, but the universal consensus by those who went to Ida Sailor rudders has been that they're great. Particularly noted is better responsiveness at slow speeds, such as in docking situations.

An Ida Sailor is on my short list, right after some overdue trailer and centerboard maintenance and upgrades.

[tmorgan]

I bought one of the last foil rudders IdaSailor sold that could just replace the flat factory rudder.  It makes a huge difference in responsiveness.  I assume the newer kick-up rudder assemblies enhance performance in a similar manner. 

[Salty19]

These are observations from comparing a CP16 with and without the IDA rudder (NACA 0012). Do a search and you'll find similar thoughts.

-MUCH less weather helm. This effects here are numerous: The ability to hold your course steady and true was vastly improved. The ability to hold your course LONGER without the automatic effect of the stock weatherhelming as quickly as it did.   On the flat rudder it would always hunt around the tack when close hauled in good wind with a strong tendency to go upwind. You were always fighting it.  After you just cruised along and sailed as hard you wanted to without the steering loosing bite and forcing you upwind. The weatherhelm did not completely go away..good for the safety aspect, it just had higher limits.

-Tiller effort was reduced significantly. When going strong, originally it took a bit of effort to hold your course.  This is due mostly to the balanced fore and aft effect of a well made rudder.  The leading edge is moved foreward a bit which for mathematical reasons I can't explain but laymanwise allows the steering to "feel" much lighter.  Before you needed a strong hand, now two fingers or a light hand.  

-Responsiveness.  No comparison, the CP16 was a slow acting boat for tack and manuevering. Slower the speeds the worse it became.  Now it changes directions with authority and great for sloppy or difficult ramp approaches.

-Tacking. While jibes were not frequent, ometimes it simply would not tack with the stock rudder.  Now it can quickly come about, in fact it's real easy to oversteer your tack!  Even with light winds, I never had to jibe again.

I have whole assembly on the CP19, but never sailed one without it.  I imagine the improvements would feel similar.  If your boat feels sluggish and heavy at the helm, this could be what what you're looking for.

[Rahn]

The new kick up rudder system from idasailor not only improves performance but made raising and lowering the rudder much easier. I have a Horizon Cat now and would trade the wheel for the idasailor if I could.