Some mast/deck bearing/rake questions….

[JonTweeds]

Got some issues with setting the boys boat up, which causing me some head-scratching, both individually and combined…
1. The “hole” for the mast foot has a notch cut out for the peg to lock the mast in, but it is facing aft, so is non- effective when in head-to-wind position. Should we turn it round?

2. At deck level, the mast collar sits very low against the bearing surface, sitting lower than deck level at the aft facing side to the point where I’m a little concerned about the effect if he wants on the mainsheet. I’ve looked at the rake measurements (see below) and it appears we should have more rake, which will increase the problem. Should we drill out the rivets holding on the collar and move it up 10mm or so (worried about extra holes in the mast down there.

3. We’ve measured at deck height that the mast position is ok (3m 25cm aft face to stern), but hoisting the tape up the mast gives 6m 20cm to stern (this site suggests 6m03-6m10). Problem is that if we sort this out I’m certain the boom will dig a trench across the aft deck!

Any suggestions greatly appreciated – mast is needlespar blacktop with a North sail.

Cheers all.

[andyt15064]

Hi Jon – re the points you make:

1. Usually the notch is at the forward end of the lower mast bearing in the boat and the peg is on the aft surface of the mast. As you don’t really want to cut another notch why not switch your peg to the forward surface of the mast?

2. The deck ring on the mast DEFINITELY needs to be level at the aft end with the deck bearing, possibly a couple of mm above. (ask Keith Byers after his experience at Snettisham last year). No problem with drilling out the existing rivets and drilling some new holes – the masts are plenty strong enough to stand a few more holes (Noble Marine is the recommended class insurer).

3. The mast head to transom measurements you quote are for carbon masts which generally are raked back further than AL masts because the lower mast bearing is further forward in the newer boats. 6200mm should be fine as a starting point, but ultimately you need to sail the boat upwind in a force 2 and assess how well balanced the helm is with the boat DEAD UPRIGHT. You should be able to hold the tiller extension lightly between thumb and forefinger. Too much weather helm the mast may need to be even more upright. Neutral or lee helm and rake it back another 10mm.

Andy

[JonTweeds]

Thanks for the reply Andy. Had another look at it today as we were getting it ready to tow to KG next week, and realised that there’s quite a bit of vertical play in the mast -pulled upwards with the notch and peg engaged the collar sits flush with the bearing surface. New plan is to cut some PTFE sheets to size, to fit in bottom of mast step. I’m presuming that what’s going on is years of wear to the mast step and/or foot of mast….
Cameron reckons he has just a tiny bit of weather helm, certainly less than on his Laser!
Cheers, Jon

[Finn]

John, You could go “modern” on the mast retainer & tie a piece of cord around the bearing on the mast.

[Bill B]

Hi,

1. You need to be careful moving the bearing ring – they are usually in the right place (ish!) to get the goosesneck the right height above the deck. You should check this first – you might need to do something to lift the whole rig. Andy is right aying that you definitely need the ring in the middle of the bearing.

2. I always start by having the boom roughly level when I sheet in for a F2 and then adjust to suit weather helm etc from there.

Bill

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