MAIN Sail alteration?

[Niander]

I need to raise the boom about 16" as there's no room for a spray hood under the boom!

so obviously the main will need altering
easier taken off the top...any problems with this plan?
and any recommendations for a good sail place to do the work?

 

[Tranona]

It will need to come off the foot and will lead to a significant decrease in sail area - similar to having nearly a permanent first reef. Any sailmaker will do it for you - about £100 if the sail is in good shape. However, not a good idea as the boat was designed to have the sail proportions as they are.

 

[Otter]

We had a similar alteration done, 12" off the top, a few square inches of area lost and yes it cost £100.

 

[PlankWalker]

As Tranona says it should come off the bottom if its a bermudan sail.
To take it off the top would need a massive headboard , extra battens, and it would still probably foul the backstay.

Plank

 

[Ravi]

I need to raise the boom about 16" as there's no room for a spray hood

16 inches is a lot! Just how much do you need a spray hood? It would be much dryer if you just stayed at home!

 

[Niander]

Yes lets all just stay at home and don't bother eh
ever been caught out in foul weather with no protection?...obviously not!
Actually it may be a bit less but will raze the boom as little as poss.

 

[Otter]

As Tranona says it should come off the bottom if its a bermudan sail.
To take it off the top would need a massive headboard , extra battens, and it would still probably foul the backstay.

Plank

No extra headboard, no extra battens, no fouling of backstay.

I suggest the OP speak to a professional sailmaker.

 

[DanTribe]

My last mainsail was made too long in the luff and had to be altered, [ the sailmaker took the measurements, not me.]
I assumed that he would just take a bit off the foot. After discussion with him he advised that the best option was to cut down the head and recut the leach. This seemed counter intuitive as there was a lot of work in altering the leach tabling, batten pockets and reef patches. As I wasn't paying I didn't mind how it was done. Final result was a proper job.
As suggested here, ask a sailmaker.

 

[Tranona]

Yes lets all just stay at home and don't bother eh
ever been caught out in foul weather with no protection?...obviously not!
Actually it may be a bit less but will raze the boom as little as poss.

What boat do you have?

There is more to raising the boom than just shortening the sail. Raising the gooseneck and probably altering the track and re-arranging the reefing points for example.

 

[bigwow]

Raised the boom on Bigwow several years ago, to fit a spray hood. Kemps altered the head of the sail, haven't noticed any problems in the 6 yrs since.

 

[grafozz]

I had the sail rip across the base of the headboard on a sudden gybe and took the chance and cut off the headboard , which consequently, raised the boom
to help clear the new bimini .
I re -fitted it and had a sailmaker check it en route in the Aegean and he said its strong enough , just leave it .

 

[wilkinsonsails]

You can always get a combined recut done ,that's say take 6" of the head and trim the leech in to the top batten,and then take a similar amount off at the clew tapering it down to the tack.
After all you just need the hight at the cockpit end.
It depends on the cut of the sail and the panel layout at the foot of the sail .

.Just chopping a chunk off the bottom will mess up the roach ,the lowest batten will be closer to the boom,reef arrangement will be closer to the boom so smaller first reef.and shorten the foot somewhat .
So not how I would adjust it if asked.
Cindy