Just wondering what people think, Im going to be getting a small sail (3.7) that rigs on a boom between 139 and 148. My existing boom only goes down to 150.

I can imagine that at full outhaul the 2cm isnt going to be too much of a gap but wondering if anyone has come up with any clever trick to get away with the 10cm gap.

Im imagining fixing to the sides of the boom as well as to the end. But maybe I just have to bite the bullet and buy another boom that will do the small sails.

I'd just cut 5cm off the boom body and redrill the adjuster holes.

^^^ Yes but then you lose max length adjust.
If you can get a secondhand tail end and tubes, drill extra holes in that (leave boom body intact) and cut a bit off the ends so it inserts far enough into the boom without seizing. Then you will have a 135 - 200 but yes, need to carry the extra end bit. If you only use the extra end with 3.7, leave it with the sail.
I do just that with a 6.4 that need 2cm extra to fit my wave booms. Cost $60 to basically make a new boom

you just might be able to drill two extra holes just in from the minimum setting, most booms have a little extra before the holes are in the tail piece, I'd push it in as far as you can before you drill the extra holes, just so you know it'll work, mark with a tester pen and drill the holes.

I'd worry about the extension just touching the boom arm when compressed. Wear causes weak spot, especially powered with small sails.
Not sure I can find an extra extension for any of my 5 different booms.

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hardpole said..
Just wondering what people think, Im going to be getting a small sail (3.7) that rigs on a boom between 139 and 148. My existing boom only goes down to 150.

I can imagine that at full outhaul the 2cm isnt going to be too much of a gap but wondering if anyone has come up with any clever trick to get away with the 10cm gap.

Im imagining fixing to the sides of the boom as well as to the end. But maybe I just have to bite the bullet and buy another boom that will do the small sails.

A 3.7m sail works better is it has a longer boom length than this, so what sail is it? Short booms can make small sails very twitchy.
(My 3.6 has a 146cms boom length.)

Do not cut down a boom just to fit a small sail. Set your 150 boom to minimum setting and then rig the sail to the correct outhaul tension. And then use an extra bit of rope to lash the sail clew so that it's still held central between the boom arms. If you do this cleverly, you can still adjust outhaul tension.


If you sail in waves and strong wind a lot then having a boom that sets at 140cms is the way to go in the longer term.

Obviously best answer is get a boom to fit the sail, or sail to fit the boom... BUT...

how often would you use a 3.7 on anything like minimum outhaul? I imagine you are rather powered up by the time a 3.7 comes out. I would suggest 5cm or so isn't a huge deal. A lot of racers use adjustable outhauls which all leave a bit of space between the clew and boom when released. If it is annoying as Basher said you could lash it with rope to stabilise it, or get a bit more creative and clamp something in place - for instance, you could make a spacer of sorts to fill the gap and centralise the clew.

I always wondered how much not having the sail clew tight against the boom tail end mattered, I use an adjustable outhaul so mine are never tight.

With big sails, matters little due to percentage and how you sail.
In small sails, matters a lot due to percentage, gustier winds, needing to survive.

Using any kind of thin line (a downhaul line is perfect but even paracord will work) run a figure-8 pattern through the clew and around the boom on each side to keep the clew centered within the boom. You won't notice the extra length at all and the figure-8 will prevent sloppy handling which would be especially disruptive when sailing clew-first..

I would not use a boom that is too long for the sail. I use an adjustable outhaul. I set up my sails so that at the max wind range of the sail, when on a close reach or working to windward, the sail is just resting on the boom and the clew is at the end of the boom. Hence when I bear away on a speed run, I let out the adjustable outhaul so the sail bellies over the boom up to the harness line and the clew is up to 50mm from the end of the boom. When set up like this, the boom length is around 20mm less than the recommended length of boom for the sail. Hence

Thanks for those comments everyone, I think I will see what it looks like rigged up and perhaps give the rope to keep the clew centered idea a go. But probably end up buying a small boom ;-) perhaps a small ali one as "maybe" there is less stress when everything scales down but the boom strength is the same. Not sure if thats true.

The sail is an Ezzy Zeta 3.7 - luff 359 Boom 139 to 148. Im getting it for foiling as there have already been a few days this season where my 4.2 was too big. I will have to get a shorter mast piece as well but trying to minimise the bits I have to carry.

So it wont be like using it for bump and jump sailing where it would be nuking to use such a small sail (I have only used a 3.7 once for that in Tarifa and even then I switched back to a 4.2).

Interesting idea of drilling more holes in the boom extension but the Chinook I use changed shape and curves straight after the last hold so even if I was going to risk it I couldn't make it any shorter.

other thing to do is to outhaul the sail and cleat it off as usual with a bit of boom sticking out, then using the same line tie the clew of the sail off to the sides of the boom so its in the middle and not to one side, that just secures it a little more than have to buy a small boom.

For foiling I do not think it will matter to have a slightly longer boom, will only matter, if at all, when you are on the water trying to get up, once you are up the sail depowers.

A true learning experience involves personal involvement, almost always.
Tthat's why the internet is not a perfect tool.

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LeeD said..
A true learning experience involves personal involvement, almost always.
Tthat's why the internet is not a perfect tool.

In some ways your right but if you have been struggling with something for ages why not ask online as theres lots of willing people with years of experience that can help.

I've tried it and I didn't like it. Getting the right boom size will be well worth it in the long run. ;)

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Sandman1221 said..
For foiling I do not think it will matter to have a slightly longer boom, will only matter, if at all, when you are on the water trying to get up, once you are up the sail depowers.

It'll matter far more for foiling because having the clew far from the boom end will make for crap pumping.

Likely also that sail will want to rig with less DH and OH to perform well foiling.

Personal experience includes sorting thru all the opinions, where they came from, how often they are reinforced, POV, and other factors.
Everyone has an opinion, but how often are 3.7 sails used by the player's involved, and at what level?

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Grantmac said..

Sandman1221 said..
For foiling I do not think it will matter to have a slightly longer boom, will only matter, if at all, when you are on the water trying to get up, once you are up the sail depowers.

It'll matter far more for foiling because having the clew far from the boom end will make for crap pumping.

Likely also that sail will want to rig with less DH and OH to perform well foiling.

Well I rarely pump the sail, its the foil that I pump.