490cm mast trim

sailwave · Joined: 11 May 2000 Posts: 113 Location: Redwood City, CA

Need to replace an ancient 7.8 North race sail but all the modern race/semi race sails have luffs in the 475-485 range. I have a very healthy constant curve 490cm mast. Is it OK to cut 5-15cm off of it and not compromise strength or perfromance? Top or bottom trim?

manuel · Joined: 08 Oct 2007 Posts: 1158

I would rather sell it and get a shorter one. The curve will be affected and you may lack flexibility up top while having too much rigidity down low.

swchandler · Joined: 08 Nov 1993 Posts: 10588

It might be a bit more expensive, but I would recommend buying the ideal mast that's the best match for the sail you buy. It's the kind of the perfect harmony that you want in the long run.

cgoudie1 · Posted: Sun Sep 20, 2020 5:39 am Post subject: Re: 490cm mast trim

If you're set on cutting, and it's a CC mast, I'd cut 5cm off each
end. Keeps the boom reinforcement at the proper height (more or less)
It'll be a little stiffer mast, which might be good if you're a
heavy weight.

-Craig

p.s. You should rig it before cutting. Sail luffs aren't always exact, and
a new race sail might stretch 5 cms and be perfect with a stubby extension
on a 490 after 2 or 3 outings.

U2U2U2 · Posted: Sun Sep 20, 2020 9:47 am Post subject:

My first thought is get the correct mast.
It may depend on how often you would use this, obvious it’s a big sail, so it’s going to have some power.

My second thought is get a sail with a vario top, and let the excess stick out the top.
I,favor this over cutting it.

If you cut the bottom, be assured your EXT will fit length wise still, the boom reinforcement area is vital.

It is a RDM or fat boy ?

NOVAAN · Joined: 28 Sep 1994 Posts: 1549

If this is a sail that you use a bunch, get the mast that its designed for. If cash is an issue, cut a little off each end. Some masts have reinforced boom connection points. Ideally you want to keep the boom head in this area. I would rather cut a bit more off the top to keep the boom on the strong point on the mast. Its a compromise but it could work out...

sailwave · Joined: 11 May 2000 Posts: 113 Location: Redwood City, CA

It is a SDM fat boy mast as cammed race sails need SDM. I really like cam sails in low wind and locked in power. Good point above that maybe it will work as is with a bit of stretch in the luff. Duotone does have the 2020 S-Pace 7.8 that is at 486cm and it ticks my boxes. Trimming off top and bottom makes sense to keep the boom area centerered on reinforced area if it is reinforced there. 7.8 is my largest sail and not much to loose on shortening it other than resale. Older 490 masts are not much in demand for resale it seems. I can always buy a new matched mast later after the bank account recovers from the sail. Thanks all for the tips.

dllee · Joined: 03 Jul 2009 Posts: 5329 Location: East Bay

Cut 5" off the bottom, was little as possible off the top.

mark · Joined: 10 Apr 2000 Posts: 181

Hi Sailwave,

I sent you a PM.

Mark

isobars · Joined: 12 Dec 1999 Posts: 20935

What does the manufacturer say?

I asked NoLimitz a similar question, and they said not to sweat the marked boom reinforcement area because it goes FAR beyond the marks to account for rigging vagaries.

Is there any visible or invisible reinforcement at the very bottom of the mast?

I really discourage PMs on a topic this general. Inquiring minds want to know, and lurkers outnumber active participants by something like 10:1.

Is there any chance that cutting any carbon mast, or yours in particular, will expose fibers you do NOT want to touch, EVER?

What do you do if your next sail has a genuine 490 cm luff and you've already hacked your mast up?

Will your mast tip plug or adaptor still fit tightly if you shorten the top? The slightest interior diameter taper could let said plug or adaptor fall out.

To emphasize two points already made:
1. Have you downhauled the snot out of this rig and sailed it a few times? They do stretch a bit. (Then there's the corollary question: No insult intended, but do you fully understand how much downhaul a race sail needs?)

2. I hadn't even thought about the variable tophaul (vario) issue, as I haven't had a sail without one in at least 35 years. If the sail you choose doesn't have one and you don't live next door to a sail loft, I'd guess most shoe repair or maybe boat upholstery shops could install one you bought off the internet. If I had either of the latter do it, I'd study a few tops on the beach and/or call a Gorge shop such as Northwave, Sailworks, or Hurricane which designs, makes and/or modifies sails regularly. There's a lot of tension up there a "civilian" may not understand. Better yet, send your sail to one of those shops and have them fabricate a vario top for you.