What to do about slightly bent mast

I'm very close (I hope) to launching the cat, but I ran into a problem that concerns me. The diamond wires were sagging when I purchased the boat, so I tensioned them according to the manual. However, one shroud is two holes from the top of the anchor and the other side is two holes from the bottom!! Am I in for trouble? I have the boat on a level surface, and I'm using a wall on the house to line the mast up with. I've not measured the length of the shrouds, but the mast does curve slightly to the right. It doesn't seem that significant, but you can see it if you look. I really don't want to purchase a new mast, so should this be safe to sail with? Thanks

Are you sure you tensioned the diamond wires evenly?

Shroud pin location in the chain plates should be independent of diamond wire tension or any mast bend. Just reposition the shrouds to make them even. It’s also worth noting that the shrouds need to be loosened before raising/lowering the mast in order to relieve rig tension to allow the forestay to be pinned/un-pinned. After the mast is up, you have to come back and tighten the shrouds. It’s possible the previous owner only loosened one side of the shrouds the last time they lowered the mast which would explainwhy they are uneven.

sm

like srm said, it doesn't matter if your mast is slightly bent or if your diamond wires are tight or loose, that has no effect on which holes the shrouds pin into. A slight bend in the mast is nothing to worry about, mine has one too from being stored on its side, supported only at the ends for a good 15 years by the previous owner. If the bend is below the top of the diamond wires, all you have to do is loosen the side it bends towards and tension the opposite side to straighten it. If the bend is at the very tip, there's no way to straighten it, but if it's slight, it's not worth worrying about.

With regards to the shrouds, there are a few things to pay attention to. First of all, the forestay has a 12 hole adjuster plate at the end, which slides into the center of the roller furler and gets pinned in. Which hole is that pinned into? If you're pinned to a low hole, it'll allow the mast to rake further aft, resulting in the shrouds being pinned closer to the bottom. You set your mast rake primarily by changing which hole the forestay is pinned into. Also, do you have 7 hole or 10 hole shroud adjusters? The H18 originally had 7 hole adjusters with longer shroud wires, and then later was changed to use 10 hole adjusters and shorter shroud wires. If you have an old set of shrouds wires, that could also result in them being pinned lower down. If you get a new set of shroud wires, you'll need the 10 hole adjusters.

When it comes to stepping the mast, I like to start with the bridle wires disconnected from the hulls and pin the forestay to the roller furler in the intended hole first. Then I pin the shrounds to the topmost hole on the shroud adjusters, and then step the mast. Once the mast is up, with my crew keeping forward pressure on the mast to keep it upright, I pin the bridles to the bows and remove the mast stepping pin. Then I have my crew grab the trap wires on one side of the boat and pull down while I unpin the shroud on the same side, and re-pin it say 3-4 holes down from the top (depending on the forestay position). Then we go to the other side and do the same. If they're still slack, or I can't pin the shroud at the same point, I go back to the first side and repin so that both sides are tight, and both sides are pinned at the same hole.

_________________
Mike

'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238

I agree with all the above comments.

If you want to measure your mast rake AND check if the side stays are even, there is a photo sequence in a specific Photo Album on my boats own Facebook page showing how I do it. Each photo has a comment about what to do and what is happening. I sail with LOTS of mast rake. It’s one of the main reasons we are fast and can point high. Don’t be shy on trying heaps of mast rake, even in light wind. If you match my amount of mast rake you may need to remove the twist toggles below the chain plate to get enough sidestay tension.

Assuming your sidestay wires are the same length, it is not a problem to have the sidestays one hole different from side to side to achieve the correct rig tension. Don’t over tighten the rig tension just to get them in the same hole. It is better to have the correct tension than the same holes. If the rig tension is too tight, the boat gets too bound up and doesn’t accelerate forward. If the rig tension is too loose it feels limp in the gusts and doesn’t accelerate forward. One adult leaning firmly on the trapeze wire or hooked in their harness (aft in the zone where the skipper would normally be on the trapeze) is about the right tension to put the pin in the adjuster. Two adults leaning or trapezing is too tight.

Once you are content with rake and rig tension, tape up the clevis pins and rings on the forestay and port sidestay and then only ever adjust the starboard sidestay for rigging and derigging purposes. That way you can always go from top hole for rigging and derigging to your desired hole for racing. One touch adjustment is all you need to do. (I went to the extreme and made a new forestay and port sidestay the exact length so I can now pin the wire direct to the furler and direct to the sidestay anchor without the need for a twist toggle and adjuster chainplates. I therefore only have one 7 hole chainplate on the starboard side, nothing else. It’s cheaper, less hassle, less to break or fail, etc. The KISS principle).

_________________
John Forbes
Hobie 18 Reimagined
Sail # 490
Boat name: 18@heart
http://www.hobie18.fun
https://www.facebook.com/Hobie18catamaran/

I've not responded back but I wanted to let you guys know the status. I loosened the diamond wires, and the mast remained crooked. The bend appeared to start below the attachment points at the top of the diamond wires, so after spending time adjusting the diamond wires, I was able to get the mast pretty straight, and using an 1/8" line, I'd say the straightness from end-to-end within is within 3/16". Also, the mast is now straight within the shroud anchor points within a hole of each other - I understand your comments these should be independent, but everything looks great now. You guys rock - I can't say thanks enough.

I've taken the boat out 3 times in the last week and have had a blast - the wind has been pretty slow though, around 12-15 mph. The first two times, we had around 650 to 700 pounds in passengers, and the second time I couldn't tack because the boat would slow too much and we'd be in irons. I had to jibe to make a turn. The last time, it was a son and me - this was the lightest wind, but it was much more fun. Tomorrow morning the gusts will be in the 30 mph but dropping to lower 20's later in the day. I'm looking forward to this.

John F, I especially want to thank you for all your assistance. Great Facebook page.

Awesome. Have fun.

_________________
John Forbes
Hobie 18 Reimagined
Sail # 490
Boat name: 18@heart
http://www.hobie18.fun
https://www.facebook.com/Hobie18catamaran/

The advice I've read regarding diamond wire tension ( Berman, White ) suggests having them much looser than the original factory manual setting.

I've got mine set so that moderate pressure allows the wires to touch the mast one foot up. This is considered fairly tight!

The idea is to allow the mast to bend when it's rotated and you add downhaul. This flattens the sail for high speed efficiency.

How badly bent is your mast with slack diamond wires?

I suspect an inch or three won't matter much, except that you might get better performance on one side of the wind vs. the other, due to the 'pre bent' mast fighting the downhaul.