18" Backstay Overlap of Mainsail

[oceanxtasea]

I have ordered a new mainsail with max roach. I have done this with the intent on cruising, not day sailing or racing the bouys. Thinking more sail area, more power for light air. I would like to here some opinions, positive or negitive. This is going on a 36' westerly corsair, sloop. It will be an 8.4oz. Dacron, full batten, lose foot with tides marine strongtrack.

[bewitched]

Mine's overlapping, and of course the advantage is more sail in light winds (fairly predominant here in SE Asia).

The only problem I have with it is when motoring with the main up - it keeps twanging on the backstay. Really annoying and probably not all that good for the sail.

I've learned that cracking off the main halyard and pulling on the cunningham gets the main under the backstay and sorts this out.

[cal40john]

Originally Posted by oceanxtasea

I have ordered a new mainsail with max roach. I have done this with the intent on cruising, not day sailing or racing the bouys. Thinking more sail area, more power for light air. I would like to here some opinions, positive or negitive. This is going on a 36' westerly corsair, sloop. It will be an 8.4oz. Dacron, full batten, lose foot with tides marine strongtrack.

My boat was used for racing it's entire life, then I bought it. The main overlaps the backstay. In light air I have to ease the mainsheet on a tack, and then jump to the backstay and start shaking it in resonance until it releases the main. Jibing in light air I have to grab the boom after the jibe, pump it to weather until the top full length batten pops over. Only then can I jump back to the backstay and shake it to release the main. Shaking it with the batten the wrong way does nothing.

In more wind I only have to ease the mainsheet a significant amount (much more than a racing tack ease main to recover speed.) to get the main to clear the backstay. I can't do lazy cruising tacks leaving the mainsheet cleated.

While a fathead is not supposed to change the center of effort much, I feel that I get weather helm earlier than I should. A sailmaker told me that no-one gets the max roach for my boat anymore due to weather helm issues.

So not worth it to me anyway.

I do have a love hate relationship with the luff length. I have a sliding gooseneck. If the sail's luff length was of a length to pull the boom up to near the top of the track when hoisted, my 17' long massive boom would swing over my 6' tall high while I'm standing in the cockpit on the sole. As it is now the gooseneck is permanently tied to the bottom of the track, luff tension is adjusted with a cunningham, and the boom perfectly lines up with my ear.

I hate the idea of getting killed by the boom, I love the idea that I have almost 10% more sail area than original for the light winds of the Salish Sea.

John

[djmarchand]

An 18" overlap is too much. I have less than a 6" overlap on my cat and it occaisionally hangs up in light air. The leech is worn a bit at the outermost batten. So I can live with 6" ok, but not 18".

[Mark Johnson]

Steve Dashew (sp?), originally drew his boats with this feature. Their huge roach mains had to be lowered about 1/3rd to pass the boom from one side to the other. Everybody should read his book, BTW. (Good ideas)

His ideas are VERY innovative, and his boats among the very best ocean crossing designs out there, (for the very rich), but this particular idea is one that really turns me off.

EXAMPLE: I have been beating up the coast of Andros, in 35 knots of wind and 15' seas, in deep water but a continuous reef 200' to leeward. When it became clear that I was going to HAVE to pop a tack, NOW, the idea of lowering my main to do so was unthinkable.

Even crossing oceans, there may be such occasions! IMO...

Mark

[oceanxtasea]

Thank You for the response. Surprised there is not more positive said. After almost one year and close to a thousand miles, I love my sail ! From the lite air to motor sailing with 1st reef to 45knt. with 3rd reef, I love my sail. My boat is still balanced. The sail does not hang up when tacking or jibing, do need to watch as it raises up into the backstay, minor inconvenience. Having gone from furling, my boat sails Great! I sail over 50% of apperant wind speed i.e. 5.4 speed in 10wind, 7.8speed in15wind, above 20wind I reef with keeping same speed, still has nice roach shape with reef in.

[ggray]

Originally Posted by Mark Johnson

Steve Dashew (sp?), originally drew his boats with this feature. Their huge roach mains had to be lowered about 1/3rd to pass the boom from one side to the other. Everybody should read his book, BTW. (Good ideas)


Mark

My recollection of what he wrote in his book (of course he may have written more than once on the subject) was that after discovering that they had added way more to the roach than expected, he did lower to first reef to tack. Then, either from tacking accidentally or just saying "let's see what happens", they tacked w/o lowering, and the sail slid through. So they stopped lowering. Got to be tough on the sail over time though.

It certainly is a good book. Dashew has had an interesting life. Used to build and sail at least one of the early "speed freaks" that held sailing speed records.
He also was the guy that built those big man figures (out of fiberglass) that you used to see along the highway to catch your attention to someone selling mufflers or what not.
Got to admire him.

[oceanxtasea]

[oceanxtasea]

]Full Batten but still sags, so shown overlap +...

[ggray]

Wow, that does look like a lot of interference.

Dashew's boats seem to have had the most overlap down lower where there could be more give from both parts.

[s/v Jedi]

Dashew liked it so much that he went extreme roach and just got rid of backstays. We have runners that go to the masthead. This big roach thing combined with ketch rig makes our 64' boat the easiest to handle.

You can sew UHMW strips on the outside of the batten pockets to protect them and make them pass the backstay easily



ciao!
Nick.