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rear cross member dimensions


fangman

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pulled the cat apart for winter check,front beams in good nick, however rear beam has cracked and slogged bolt holes.I have acquired a cobra mast section,problem is I do not know what exact positon for the holes eg[ distance between bolt holes on one hull to the bolt holes other hull] and is this all I need to get proper hull alignment.Can anyone help

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Fangman

I would expect that if you set both hulls paralell and square, (using the front beam to get your width), you could then just mark the hole positions using the holes in the hulls as a template. Every boat is liable to be slightly different in width I would think espcially the mark 1s. This way you know that your hulls are parallel at least. To get a measurement for parallel I would measure off the centre of the eye for the shroud on the bow/(pointy end) and use the centre of the rudder pintle on the stern/(flat end) (land lubber terms in case mick reads this also) someone may correct me on this though.

Phil

[This message has been edited by korwich (edited 01 July 2008).]

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Tension dolfin as per rigging tips in maricat website, if I remember right with no tension measure the amount of rise then tension so as that measurement is increased 10mm. The force of the mast then should push that back to the original measurement. I'd check that info myself before doing it though. Therefore I suppose that it would make sense to parallel before tensioning the dolfin strkr as it is pushed back to original by the mast. Hope this makes sense.

Phil

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Not sure what the original was, I used fibreglass car dent filler ie plastibond. Had everything ready and lined up spread the goop in there and tightened up the bolts. On my front beam I had one of the nuts strip on me, so I drilled it out so the bolt fitted through it and put in a longer bolt with a washer and nut with access thru the hatch. Worked well but I still needed to seal up with sealant to stop the water from getting in, even more so as I had a hole going into my bouyancy tank now. The goop sure helps to stiffen it all up, along with tight bolts and a tight tramp.

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G'day

Just happenned to be passing by and noticed the recommendation to use Sikaflex. I use it a fair bit and it's a great product but I don't think it's the best thing to use for bedding beams. There are a number of different grades, but most are very strong adhesives which have some flexibility. So once you use it in the beam seat it will be very hard to ever get the beam off again. Also the inherint flexibility means a bit of give in the hull to beam joint. Probably not what you need for a stiff boat. I would recommend bogging in with the car stuff or a microballoon or Q cell mix with polyester or vinylester resin. Apply Gladwrap smoothly to the beams then tighten them down to squeeze out the excess before the bog goes off. When it dries take the beams off, remove the Gladwrap and you should have a nice matched beam pad. This will still give you at stiff boat but allow you to easily remove the beams if you need to. A small amount of silicon around the bolt holes will stop and leaks too if you are through bolting or some petroleum jelly if bolting to a threaded insert in the beam pad.

Hope this helps.

John Dowling

A Class

Stingray

Arrow

Seawind 24

MG 14

When too many boats is never enough

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Hi Guys,

I agree with John about sikaflex . I used it to bed in beams and I am having all sorts of trying to get my hulls apart again. Johns advice makes good sense to me. I will never use it again. Meanwhile I will keep pecking away trying to get them apart. Any suggestions welcome

Rob Rimington MPYC

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