Wonky masts

[Guest Tim Whitford]

My mast rotates different amounts on each tack. It is a US mast section. Sick and tired of running out of adjustment on one side every race, I built a new mast. Hand picked it from the selection at Malcolm's factory. Chose the one with the most symmetrical bend there was. Had it anodised, custom fittings, roll swages and turnbuckles everywhere. It's worse than the old one. Has anyone got a solution???

P.S. Anyone want to buy a brand new mast, only sailed one leg?

Cheers, Tim

[John Brett]

I bought a mast at the same time as Tim and have not evaluated it properly yet but I checked it out before fitting it out and it has 3 1/2 deg twist along its lenght. I don't know if there are tolerances set on this product but that does seem excessive.

Cheers, J.

[Guest Tom Serna]

I have an older mast section, kind of a weird one. it is anodized black and the sail track is an external extrusion, actually it kind of looks like a windrush mast but a size thinner maybe. I find that you have to pull more vang on again from when you tighten the last couple of feet of mainsheet to keep the desired rotation but thats to be expected. the top of the mast is also usually symmetrical with the line of the lower forestays when you tighten them, but I am told this is normal too. I have some pictures here , I could also take some closeups of the spar if you want.

http://www.catsailor.com/gallery/thumbnails.php?album=54

[Dave]

G'day Tim,

Many people do put up with this situation. However, the critical issues are:

1 - mast bends equally both ways (sideways);

2 - no twist over the length of the mast;

3 - fittings attached very accurately;

4 - symmetry in critical fittings.

It sounds like you've taken care of the first two fairly well.

The third point refers to the fittings that affect how the mast rotates, namely:

a - hounds (uppers and lowers);

b - mast spanner (rotation device);

c - gooseneck (if fixed, ie not sliding);

d - sail halyard hook.

The hound position is critical and needs to be fitted very carefully. Finding the centreline of the mast at the front is the key. This can be done by using a piece of card or paper and using it to measure around the mast from the track at the back. The average of two equal distances (one on each side) will indicate the true centreline.

The mast spanner needs to be fixed with the bolt perpendicular to the centreline. This is an area that often causes this problem, so don't underestimate it.

If you have a sliding gooseneck, as most PTs do, this shouldn't be a problem. But if it is fixed, check that it is centred accurately.

The sail halyard hook shouldn't cause too much problem, but is worth investigating if all other parts are accurate.

Point 4 above (symmetry) refers mainly to the mast spanner and the hounds. The mast spanner may have the pivot bolt accurately fitted, but if the spanner arms aren't symmetrical, this can cause the problem. Also, check out the hounds, as they are often misaligned straight from the factory.

Lastly, symmetry can also affect the stays. Check the length of each stay compared to its matching pair. With the mast not rotated, hold matching stay pairs straight down in front of the mast, nearly touching the front beam, and compare their lengths. You may be surprised at the results. Obviously, you can only check (unattach) one pair at a time, otherwise your mast will fall down!

Anyway, I hope this helps. Let me know how you get on.

Dave Stumbles

Publicity Officer

Paper Tiger Catamaran International Association.

[Guest Paul Willyams]

I had a similar problem - the spanner would not stay rotated on starboard tack, but would pop back to windward. No such problem on port tack. Also, even with the spanner in the correct position, performance was noticeably different on each tack.

With helpful suggestions from other PT sailors, I have:

- reduced rig tension (was very tight - pre-bent)

- increased mast rake (was upright)

- shifted the mainsheet block closer to the end of the boom (increases pressure on the spanner to encourage it to stay put)

This has significantly reduced the problem, however I suspect the mast is still saying 'replace me'.