trintella 29 chainplates

[Ardenfour]

the lower shroud chainplates on my boat consist of a stainless bar which protrudes above deck with a hole for rigging screw pin. Below deck, the stainless bar cannot be seen - what is visible is a mild steel bar with 4 bolts, needless to say in an advanced state of corrosion. The bolt heads look as tho they would disintegrate at the first attempt to undo them. Has anyone any experience of this method of construction? Do I have to grind off the bolt heads to remove the mild steel parts? Are the bolts likely to be tapped into the stainless steel bar? The chainplate itself seems to be buried under the grp. There are no nuts or bolts visible on the hull exterior

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[sailorman]

Hi Peter
sorry to hear of your props & have followed your previous posts
i used to fit-out the Trintella 1 ( 29ft) @ Offshore Yachts.
it seems to me that u have must have bought a home made boat, did u invest in a Professional Survey prior to purchace.
the original chain plates were similar to your 23 made by Alpha
roger

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[halcyon]

Have you checked the owner's web site http://www.oycoa.org.uk, may be something there.


Brian




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[Guest]

If all else fails

The remedy would be to grind off - then drill out the bolts exiting the exterior of hull.

But first of course check with every source you can find ..... owners assoc., yard fitters, forums ...... etc. This may be a job that has a suitable solution arrived at by another.

If you do drill out etc. - then only exit enough exterior to have a small hole guide ..... then drill from outside to preserve the gel around the hole .... When drilling check whether you have any coe material and this will have to be dug out and replaced with resin to strengthen the area ....... finaly job is to fashion 2 stainless plates to fit ... 1 exterior hull, 2 interior instead of the mild steel one. Bolt through with stainless bolts. I would suggest a resin mix under the plates to assist in a) fixing the plates, b) to seal the hull against water leaks.

Often when working on chain plates that pass through deck etc. to holding plates - they are disturbed in the work and then leak .... so good idea is once all bolted up - to gouge out around the plate on deck and cleanly fill the gouge - sealing the plate again.

Oh yes - make sure when doing the job that there is no weight at all on the chain plates when drilling through etc. You don't want them to move !!


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[Ardenfour]

Re: If all else fails

Thanks to all who replied. No, didn't get a survey, but had spotted the condition prior to purchase - reflected in price. Have tracked down first owner who apparently has still got original building plans which may shed some light. Does grp have more strength when subjected to a lifting force, as when a u-bolt is fitted with a backing plate under a flat deck? or when subjected to a sideways force (shear?) as when chainplates connected to the vertical hull? Haven't got the boat moved to my neighbourhood yet, so have not been able to inspect plates in detail.

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[Guest]

Re: If all else fails

Have a gander around many a yard and you will see many variations on similar 2 themes ...>
1. Vertical plates bolted below the hull to deck joint, culminating in vertical tang above deck for stay to connect to.
2. U-bolts or similar through deck to large backing plates under the deck

Obviously 1. is probably the strongest and also benefits from not pulling on hull to deck joint, it uses the hull to carry a load as well as the deck.
2 relies on the deck being securely fastened down ..... most decks now are bonded and bolted so does not constitute risk.

There are boats such as my Sunrider that use U-bolts down through the toe-rail moulding and small plates only ..... it has survived 30 yrs and still in good condition.

It will be interesting to compare with original plans - so the answer may already be coming into your hands via those.

As already said - If all else fails - stainless plates and through bolting hull would be my first thought..... careful checking for feasibility .......


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[kds]

Peter,
I have just completed a T 29 from hull and deck mouldings, including, 0f course, chain plates. I do have quite a few original drawings from Tylers ( who moulded them) and would be happy to loan these or talk you through it if you wished. Yours is not original.
The U bolt solution is the one I used, but instead of the teak toe-rail I fitted a very substantial Alloy section, which enabled the U system to be an easy answer.
email me ?
Ken

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