We were out on Lake Ontario when i heard a noise coming from somewhere around the mast. The winds were about 12 knots with about 3 foot waves. We were on a close reach, and with the waves hitting the side of the boat, there was reasonable motion The attached video contains the noises.
I suspect loose wedges but have found that all of them are tight and not bottomed out.. They are wood and I wonder if replacing them with plastic ones would solve the problem.
Before buying the plastic wedges you should check and make sure that the bolts at the base of the mast are all tight.
Mark Powers
rompinronnie
(Ron Schryver "Alpha Waves" 1987 NS30U Georgian Bay Midland ON)
5
Hi John, the noise sounds like the dreaded âmast clunkâ. If so, itâs easily fixed by snugging up the bolts that hold the mast inside the mast base. Be careful not to overtighten the bolts because the bolts are stainless steel and the mast base is aluminum and can easily be stripped.
Ron
Ron & Diane Schryver
âAlpha Wavesâ 1987 NS30U #393
Georgian Bay Midland ON
It sounds like mast noise to me. I had similar noises and eventually replaced my wooden wedges with plastic ones and am quite happy. One word of caution â the only way to check the set bolts at the base is to loosen the lock nuts first and then check the tightness by loosening them first. Donât just try and tighten them. This will tell you if they are seized in the shoe. If so, I believe I have a lengthy email on that subject. My advice to anyone is if you are going to check for tightness, take them out, run a thread chaser and then screw back in with Tef Gell coating the threads.
Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA
John, I listened to your video a few times and the sound to me, is more like creaking. Reminds of âbulkhead creakâ, which I have on another Hinterhoeller boat⌠If so, sailing close in high winds and waves could be stressing the hull and the mast.
I agree with others to carefully inspect the 4 lateral bolts in your mast step. Years ago I broke one of the bolts trying to remove it. I have since used a UHMD plastic wedge in that quarter of the step.
I agree with Greg â to my ears this also sounds like bulkhead creak.
A bit of background: Hinterhoeller boats were built on the monocoque principle â the hull itself is the structural element. There are very few true bulkheads, except where high loads (like the freestanding mast) need support. The interior panels and âbulkheadsâ are mostly cosmetic, set into slots in the liner.
What youâre hearing is the hull flexing under sailing loads. The interior liner doesnât flex with it, so the fit between hull and liner changes and starts to bind. The interior panels then hold the liner in shape, and as they shift slightly against each other, the creaking noise appears.
I wouldnât worry too much â I canât imagine there is a single Nonsuch out there that doesnât creak under sail. Except for the dock queens, every Nonsuch thatâs actually sailed will make these sounds. And the bigger the boat, the more it will creak: the smaller models have relatively more bracing and smaller panels with smaller load paths, so they stay quieter.
Thank you everyone for the good advice. I backed out the two mast step bolts and covered the threads with stainless/aluminum anti seize compound, before re-tightening them.
I also checked the deck collar bolts and was surprised I could relatively easily tighten them up a half turn or so. They were almost inaccessible but my ratcheting box end wrench managed to squeeze in.
I will install plastic wedges when we launch in the spring.