Mast Rake for 240

Alan · Jul 5, 2011

Mast prebend and rake are not the same thing. Why do you want to change the rake and/or prebend ??

Alan · Jul 6, 2011

When you ordered your new main did you measure the boat or did the sailmaker? When the sail is built a luff curve to match the amount of prebend of the mast is part of the sail design. You cannot arbitrarily change one without changing the other. Do not assume the other boats have their rigs tuned correctly and yours wrong. Many skippers don't have a clue about proper rig tuning.
My suggestion would be to set up your rig with a tuning guide and use the luff curve of the new main to set your prebend. Set the mast rake at 1 to 2% and test sail your boat. Do not 'guess' at how the rig should be tuned. Follow the correct procedure and get it right. A Loos gauge is an invaluable tool that you should use to make your adjustments.

isaksp00 · Jul 12, 2011

Do you want to make the mast more straight or more bent? Isn't the 240 a fractional rig? I would think that tightening the forestay will pull the "middle" of the mast forward, bending it more. So if by "straightened out a little" you mean less bend, maybe loosening the forestay is what you want. Does the 240 have swept back spreaders? On my H23, tightening the uppers seems to bend the mast more, so maybe loosening those will help? The lowers seem to only control how straight the mast is, not much about bend or curvature. I tighten my uppers so the mast is vertical athwartships (I just do it by feeling how tight they seem, since I have no loos gauge), using a long tape measure to measure side to side. Then I do the lowers until they feel right (who knows how close I am) and the mast is straight sighting up the track. If I ever see looseness on the leeward shrouds, I'll tighten 'em all a bit. So far, so good.

Alan · Jul 15, 2011

I fear you folks don't understand the use of forestay length, mast rake, prebend and rig tension. The length of the forestay is what controls mast rake, period! It is NEVER used to adjust any rig tension or prebend at any time. Prebend and rig tension are the domain of the shrouds. The cap shrouds increase prebend with increasing tension, the lower shrouds reduce prebend with increasing tension. After the rake is set (first thing) the prebend and shrouds tensions are adjusted.

cephius (Dave) · Jul 19, 2011

Here is a great link to specifics on how to setup your mast. I hope this helps.

http://h260.com/rigging/rigging.html

Sublime · Jul 20, 2011

hunter240 said:
I would like to take some of the rake out my 240's mast. It was rigged by the co. I bought it from and is more severely raked than other H240's I have seen. It does help in pointing better. Since the bend has been in there for so long (10 yrs), can it be straightend out a little?

I am guessing I have to loosen the outer shouds to the spreaders and the inner upper shrouds to the top of the mast and tighten the forestay.

First, before you adjust anything, get a loos gauge. This is how you tell if your rig is tuned correctly. You sight up the mast, yes. But you need to know how much tension is on the stays before moving stuff around. Checking the tension is part of maintenance on a sailboat as things stretch over time so you should have a loos gauge anyway.

When I got mine, the rigging was too slack. It had about 100lbs of tension and had been out for a few sails that way.

I'm glad I never took it out like that! I used Dave's link to adjust mine. I'm not racing or anything, I just want the mast properly supported.
I think a lot of new owners assume it's somewhat tuned by the factory which is why yours may seem to have more rake than others.
Mine wasn't. Or, it had stretched quite a bit since new. But that much too slack I doubt was from stretching.

Have you talked to the manufacture of the sail? I assume the previous sail on there was a stock sail which fit properly, yes?