Bent Boom

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February 6, 2011 at 13:15 #4991
Ronar M
Ronar M
Participant

Hi
Ronar M has a bent main boom. It is bent sideways. I only noticed it last winter (09/10) and didn’t measure its deviation so am not sure if it has got any worse between then and now. Is this a common problem with the Nic 38 boom? Does it matter? Has anyone had the same problem and successfully straightened their boom? If so, can you advise me how to set about it?

On a similar topic, do all Nic 38s have the same poxy set up for the mainsail outhaul? On Ronar a thin piece of string emerges from inside the main boom near the forward starboard side. It is probably attached to some tackle inside the boom to give it some mechanical advantage but is not really man enough to tension the foot of the main. Also I’m can envisage the string snapping some day when I’m pulling it and putting me overboard. I am deeply suspicious of any gear hidden inside spars and would like to fit a better, beefier system outside the boom. Has anyone done this and, if so could they let me in on the secrets of their system?

Cheers, Trevor

February 6, 2011 at 21:55 #8631
Van
Van
Participant

Hi Trevor,

I 100% agree about the poxy outhaul. I also have had visions of getting flung overboard when it breaks. I’ve resorted to easing the sheet and letting the sail flog a bit to minimize pressure on the main.

I believe it has a 3:1 mechanical advantage inside, but I did not measure accurately (just used my hands to measure how far the outhaul moved when I pulled the “string” a set distance). Hoping to inspect it, I tried to get the end fittings off the boom and failed at both ends. I even resorted to an impact driver. The SS screws are impossible to move.

Looking forward to hearing how you implement an external outhaul! Our boom is already a bit of a mess of lines – 2 reefing lines and lazy jacks.

Re: the bent boom, unless it’s badly bent, you might be better off just ignoring it. It’s not good to bend metals past their elastic yield point too often.

Van

February 7, 2011 at 17:22 #8651
Ronar M
Ronar M
Participant

Hi Van

Thanks. Will do some research and let you know what I come up with for the outhaul. Ronar also already has reefing lines and lazy jacks as well as a preventer line festooning the boom.

My brother-in-law, who is an aircraft engineer from Nashville Tn and is currently visiting us over here, reckons that aluminium ‘creeps’. They use this phenomenon to bend the panels for aircraft wings using heat and a vacuum chamber. He thinks that if I can arrange to apply sustained moderate pressure on the boom for several weeks it might well ‘creep’ back. I’m thinking of a couple of trees and a 4:1 tackle. Again, will report back. Trevor

March 5, 2011 at 11:49 #8821
Ronar M
Ronar M
Participant

Hi

I have now had time to measure the deviation of Ronar’s boom. I stretched a string from one end to the other and was surprised to find the maximum deviation was just over 3/4 inch. Such a small bend looks huge when viewed end on. I turned the boom through 1/4 of a turn using the old reefing worm gear, placed some blocks of wood on the cockpit roof under the area of maximum deviation and applied the mainsheet. Again to my surprise it was very easy to get the boom straight. To ease possible strain on the cockpit roof I tied the main halyard to the boom by the blocks and winched that up. Then I hauled down on the mainsheet some more to put the bend the other way. Left overnight the boom spring back when released next day, perhaps a little straighter than it started though I didn’t have time to measure it again. Maybe a few months of ‘traction’ would do the trick – next winter perhaps. Trevor

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