Extra-Large Roach Mainsail

[ozskipper]

Originally Posted by klubko

Hi,
we are shopping for a new mainsail and we want to try an extra large roach that would extend over the backstay to beef up our sail area and also to all those interesting perks that seem to come with the extra roach. Our main source of information about these sails comes from the Cruising Encyclopedia by Dashews.
Do you have such a sail and if so what are your experiences, good or bad? Can you offer any tips before we have it made?
Our boat is 31', 4.2 tonnes displacement, original mainsail little over 20m2.
The basic idea is:
- Dacron 8oz
- Full battens and loose foot (sic)
- Three reefs
- 1st reef allows tacking without hitting the backstay
UK Hasley in Hong Kong seems like the right choice in SE Asia.
Many thanks for any comments
Petr

Everytime the sail hits the backstay its going to chafe somewhat. Just a poofteenth each time, but it will ultimately have a shorter life. Similarly, the patten tips will also get a wacking each time.

The larger the roach, the more full length battens you will need to hold the sail in shape.

Fully battened mains are good to work with. flaking is much easeir. Although the sail becomes slightly heavier.

The larger roach will have more power up top giving you an extra boost in light to medium air. but its more likely you will have to reef earlier as a result of the higher COE (Center of Effort). The COE will also move slightly aft and may affect weather helm slightly.

You may also want to talk to a rigger to ensure the top of your mast and rigging can handle the extra loads aloft.

Otherwise they are very powerfull and easy to handle sails. Have fun

Cheers
Oz

[klubko]

Oz thanks a lot. Your comments confirm what I've learned so far. We have full battens now and like them a lot, even without lazy jacks, which we are on the todo list. The most interesting part of the story as presented by S. Dashew (and I've heard the similar from a cruiser we've met last year who had such a sail), is that heel is reduced and you can carry the sail a bit longer. The argument is, that regular sail produces more drag than lift in the upper portion of the sail, while the big roach works the opposite way. I am able to follow this argument, but being otherwise aerodynamical dilettante, that's about as much as I can do, other than ask people who saw this effect happen.