filling holes then re drilling in bottom of fiberglass ski boat to fit Finn

johno77

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Joined
Oct 25, 2013
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18
HI To start with please excuse my spelling its been a long day and its late here.

Needing some advice.I am fitting two finns to the hull the hull is around 18mm thick.Looks to be made of wood fiberglass and gelcoat.
I have access to both sides.There are bolt holes in place from the ski pole so will be utilizing two of these holes that align with holes in fin.Now upon fitment when trying to center fin(ski boat is upside down so easy to get at)I could not get the finn to alighn with back finn because the bolt holes are slightly off.So i made the existing holes a little bit biger by drilling to the right and now the finn alighns with other finn.I used the same size drill bit put it in the hole and moved it across one hole originally was worse then the other and not straight.There is about 3-4mm gap one one side of hole.

In hind site I should of filled the holes to start with then reentered finn to where i want it.
The ski pole sleeve will be a okay because im making a new one.

Okay so what do I do?I need to refill holes and the drill out thats my thinking.Or i could just have the bolts loose and fill with silastic like i will anyway.Its just that the holes are biger now.

What can i fill it with?iv heard a good quality car bog works well.The holes will not be seen under finn.

What about gelcoat or flow coat mixxed with talcom powder and catlist?or is this for just for gelcoat repairs?

I do have some fiber matt and epoxy i think the bottle said and catlist and maybe some harder.(it came in a kit from bunnings like a home depot.)
I want something strong eneough so when redrilling it the sides of the origional holes dont flake of.

I do have gelcoat mek and flow coat and boat talc powder.

Bear in mind i dont have access to much here in this town.If your over the blue yonder maybe you could check out bunnings and see what i have avalible or supper cheap.

Cheers in advance
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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47,562
What can i fill it with?iv heard a good quality car bog works well.The holes will not be seen under finn.

What about gelcoat or flow coat mixxed with talcom powder and catlist?or is this for just for gelcoat repairs?
No No No No No

Never used automotive filler on a boat, especially below the water line.

Ever

Talc in automotive filler does not do well with any moisture

all the answers you need are in link 14 https://forums.iboats.com/threads/how-tos-and-other-great-information.283508/

to patch a hole, you need to bevel both sides of the fiberglass and build back up. especially under the water line. a mix of chopped fibers and resin can be used a bit to fill in a very small void. however for your 3-4mm offset of the hole. you should plan on a patch area about 100-125mm in diameter, beveled in on both sides. then when completed, re-drill the holes in the proper locations

we will need pics of the hull on both sides to be able to answer and give proper advice on the repair.

is the hull cored? if so, is is balsa wood? if so, is the core dry?
 

johno77

Cadet
Joined
Oct 25, 2013
Messages
18
Hi thanks for the reply,could i put a link in here to you tube and share a video?
 

johno77

Cadet
Joined
Oct 25, 2013
Messages
18
Holes are bigger then what I said probably 6-7mm bigger.
Here is a link to videos

Thanks for your time.
 
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