OD18 - NH Technical Questions

[Fair WX Pilot]

Hi,

I'm building an OD18 with a thread in "Builders Power Boats" but am starting to get a list of technical questions so thought I should start a topic in the correct part of the forum.

I have to drill some holes in my transom and fill them to eventually take the screws from my trim tabs. I had originally planned on using wood flour and chopped glass strand to fill the holes but am now wondering if this will be strong enough to take the screws and load exerted by the tabs. Can anyone offer any advise on this?

Thanks.

[TomW1]

Hi,

I'm building an OD18 with a thread in "Builders Power Boats" but am starting to get a list of technical questions so thought I should start a topic in the correct part of the forum.

I have to drill some holes in my transom and fill them to eventually take the screws from my trim tabs. I had originally planned on using wood flour and chopped glass strand to fill the holes but am now wondering if this will be strong enough to take the screws and load exerted by the tabs. Can anyone offer any advise on this?

Thanks.

Just drill the hole a 1/2" longer and wider and you will be fine. I'll be doing the same thing this spring.

[Fuzz]

I do not think you will need anything more than wood/epoxy glue to hold the screws.
I have not tried this but you could do an experiment. Take a piece of scrap 2x and drill a half inch hole in it. Fill with wood glue, let it go off. Drill a pilot hole and inset screw. Now try to pull it out. Might even do two with different coarse screws. Report back and let us know. I would like to know but have not taken the time to do it.

[willg]

I have EZfillet on hand (essentially wood flour), so that's what I used to accept the trim tab screws on my boat. I don't think they're going anywhere.

[Fair WX Pilot]

Many thanks for the advice, just wanted to make sure I was on the right track. Wood flour and chopped strands it is.

[joe2700]

I don't know if you would need it for this, probably not, but there are high density epoxy fillers that are designed for mechanical fasteners that see high load. Gel magic would be the system three(pre mixed) version I think, as opposed to the ez fillet. With west it's the 404 filler. If something will see a very high load drilling oversized then filling with high density filler is the way to go, sometimes with a g10 backing plate as well.

I like west's guide on mechanical fasteners, no matter which epoxy you are using. http://www.westsystem.com/ss/bonding-hardware/

[cape man]

Marine epoxy and wood flour is all I used throughout the build and nothing has failed in 8 years. It will be stronger than the wood you drill out.

[Fair WX Pilot]

Hi Everyone,

After a short work enforced break I'm just about to order the fiberglass kit for the boat. The plans only call for 12oz biaxial up to the stile line (spray rail) but I want to glass up to the rub rail like others have done to help with abrasion resistance and checking etc. I am trying to keep the weight down as much as possible so was wondering if the 4oz Dynel cloth sold by BBC would be suitable for use above the rub rail with the 12oz biaxial as per drawing below the rail.

I would love to hear some opinions on this as I have never used the material and don't know how it compares with regular fabric. It would be a shame to cover the top panels with it to find it wasn't tough enough and served no purpose.

Thanks.

[bateau-webmaster]

Dynel is good with abrasion resistance, but I'm not sure how well it will wet out and fair on a (relatively) vertical surface. It is a relatively coarse cloth weave, even compared to our 10 oz woven cloth. Personally I would suggest either a 10 oz woven layer, or continue on with the 12 oz biax. I just think the Dynel will be difficult to deal with if it isn't draped over something to hold it in place.

[jacquesmm]

Or get some of our light weight glass, 4 or 6 oz.