I have a Severne Focus 8.5 sail and an Ezzy 7.5. The manufacturers? recommendation is a 460 ( IMCS 25) mast for both. I have now had a good deal on a 490 75% carbon mast ( IMCS 29). Can I use the 490 instead of the 460 for both? My new 75% carbon mast is better than my current 460 ( 40% carbon). Probably lighter as well. I?d like to switch to it. Any comments/suggestions?

Thanks

Francone

Firstly what make of mast is the 75%

The weights will be the same but the 490 mast will make the sails not twist off as well as the manufacturers intended. Severne sails like hard to masts and from what I know Ezzy's aren't too mast specific.

To get the best out of both sails I would sell both masts and get a 100% carbon 460 hard top mast

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mcross19 said..

Firstly what make of mast is the 75%

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The weights will be the same but the 490 mast will make the sails not twist off as well as the manufacturers intended. Severne sails like hard to masts and from what I know Ezzy's aren't too mast specific.

To get the best out of both sails I would sell both masts and get a 100% carbon 460 hard top mast

Both my 75% 490 and the 460 are Gun Sails masts. If you say that Severne like hard masts, then I gather that the 490 is O.K. with the 8.5 Severne, because it is IMCS 29, i.e. even harder than the 460 which is IMCS 25.

Thank you for your comment

Francone

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mcross19 said..

Firstly what make of mast is the 75%

The weights will be the same but the 490 mast will make the sails not twist off as well as the manufacturers intended. Severne sails like hard to masts and from what I know Ezzy's aren't too mast specific.

To get the best out of both sails I would sell both masts and get a 100% carbon 460 hard top mast

Select to expand quote

mcross19 said..

Firstly what make of mast is the 75%

The weights will be the same but the 490 mast will make the sails not twist off as well as the manufacturers intended. Severne sails like hard to masts and from what I know Ezzy's aren't too mast specific.

To get the best out of both sails I would sell both masts and get a 100% carbon 460 hard top mast

^^ No he was referring to bend curve not overall stiffness. Severne sails usually have a mast that is slightly stiffer in the TIP than most brands, Ezzy is about the middle, and Neil Pryde have a tip that is more floppy. So you can see a NP mast in your Severne sail will probably not work.

The Gun masts in your example are actually the same. IMCS takes length into account - so your 460/25 is the same as a 490/29. The longer one is stiffer but because it is longer it behaves the same. Like you can't bend a pencil......... but a 1m length of same wood you can bend by hand. So to make them behave the same, you make the longer one a bit stiffer.

So this question is very very hard to answer. If your sails were the same brand you would have much higher chance of success using a 490 where it is not intended (ie on the 7.5). Not only do you seek to use a longer mast than intended (sail will behave a little differently on 490 vs a 460 with 30cm extension) you may have a bend curve mismatch with one of those sails.

maybe consider getting rid of one sail and the mast and buy another if you can? Simpler..

Hi Mark
BTW what mast you recommend for Gaastra sails ?
I have problem with sail 8.0 not getting all the power you could expect. Also cams doesn't turns and sail is too flat (not much belly - but when try even more down haul is getting even flatter and less powerful)

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Macroscien said...
Hi Mark
BTW what mast you recommend for Gaastra sails ?
I have problem with sail 8.0 not getting all the power you could expect. Also cams doesn't turns and sail is too flat (not much belly - but when try even more down haul is getting even flatter and less powerful)

hey peter u could try a naish mast if u arent able to locate a gaastra mast they are a similar curve/stiffness ..sorry to butt in

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Mark _australia said..

...
The Gun masts in your example are actually the same. IMCS takes length into account - so your 460/25 is the same as a 490/29. The longer one is stiffer but because it is longer it behaves the same. ...

That's a bit confusing. IMCS takes length into account in the measurement so that length doesn't matter. A 460 25 will (in theory) always measure at 25 even if you shorten it.

The IMCS 29 is considerably stiffer than recommended and the 490 is longer than recommended so you'll find that:
a) It may be just too long. If the sail doesn't have a head strap it will may rig too high off the deck.
b) To rig it so that its looks right you will need a lot more down haul tension and outhaul than designed for.
c) It will not flex freely at the top to release for gusts. If you are a heavy sailor that may be ok.
d) It will have too much belly so it wont be as slippery as you might like.
e) I dont think the Focus has cams. If it did you would have rotation problems and possibly cam damage. Even without cams you may have rotation problems with the battens getting hung up on the wrong side of the mast.

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Macroscien said...
Hi Mark
BTW what mast you recommend for Gaastra sails ?
I have problem with sail 8.0 not getting all the power you could expect. Also cams doesn't turns and sail is too flat (not much belly - but when try even more down haul is getting even flatter and less powerful)

I think this is caused by a mast too stiff in the top. A mast too flexy in the top will be the opposite and have a big belly and a really floppy head. Didn't Gaastra move away from stiff top in recent years, or was that Maui Sails?

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Squid Lips said..

Macroscien said...
Hi Mark
BTW what mast you recommend for Gaastra sails ?
I have problem with sail 8.0 not getting all the power you could expect. Also cams doesn't turns and sail is too flat (not much belly - but when try even more down haul is getting even flatter and less powerful)

I think this is caused by a mast too stiff in the top. A mast too flexy in the top will be the opposite and have a big belly and a really floppy head. Didn't Gaastra move away from stiff top in recent years, or was that Maui Sails?

Gaastra changed from hard top to 12% a couple of years after Dan Kaseler took over from Barry Spanier. That was ~05 so say 07 for the change. They have changed since I think but I dont know how.

I'd try a common 12% CC mast and see if the sail likes it. (borrow one)

If you are ever in doubt just buy the sailmakers recommended mast that way you shouldn't get problems and the sail will feel like the manufacturer intended. This applies even more to cammed sails where it is pretty much a must.

Some sails, especially smaller less battened sails are less dependable on mast stiffness and other manufacturers masts will work just as well but you will have to talk to people to ask their experiences of this. At the end of the day it all comes down to conditons if it is windy and you are on the ragged edge you will notice the difference a lot more.