Gunnel Repair, attaching and shaping

[Keevers88]

Hello Ausfishers,

I have a question for you out there with experience in the field of Fibreglassing and Gunnels. Long story short I got the hull, 16ft Musting half cab, which someone was converting to centre console. I got the hull with the transom removed, gunnels cut and cab missing. I need to know-
How to attach the pieces of gunnel back onto the hull skin?
How do I re-shape the vertical inner side of the gunnel to provide strength back into the gunnel? (highlighted)
I have replaced the transom, stringers and floor and done all the glassing, tabbing, and fileting myself. So I know how do it just don't know what is the best method and provide the most strength. My thoughts are to screw a pine baton to the underside of the gunnel and then use this as a base to layup my glass (the pine batons have curved edges which will give me a nice line and make it easy to glass), though i'm not sure if this is going to hold up structurally once I remove the pine batons. was also thinking about completely removing the cap around the boat laying upside, creating a mould for the gunnels and laying the glass in this way, once dry flip it back over and put back on the boat but then I still have the question of how do I stick the cap back onto the hull.
Thanks all,
Keevers
p.s I live in Townsville so if there is any local glassers that read this I am willing to pay(quite well) someone as a consultant to come over give me advice and tell me the best way to go about this. 107057107058107059107060107056

[Rip it up]

I'll have a crack at answering your questions.

Assuming that you plan to keep this as a centre console you want to create a upside down u shape around the perimeter for strength and leaning against etc.

First those rear corner gunnel pieces.
Straight lines along the topsider are the most important thing from a Respray point of view. So personnally I would use something like 40 x 40 pine batton to support the loose piece from the inside. Aligning the three flat sections. Either clamp the timber or a series of button head screws to secure the work pieces. 12:1 taper grind the lap join were it was cut across. A few pop rivets into the flange around the gunnel rubber edge will secure the top and bottom. Masking tape the gap left from the cut line. And lay up some overlapping strips ensuring you get it higher then the surrounding areas. This gives you something to grind back.
Once cured you should be able to release the clamps and pine Battons. Grind out from inside and finish it off.

If successful you will have minimum distortion of the flat panels and a quick fairing putty wipe over should see it disappear.

The front edge you talk about is a simple project. My approach would be to use a series of 3mm plywood strips to get the desired curve. Hot glue is your friend to get started. Strip up a few layers of 50mm wide 3mm bracing ply. Start by securing the bow end of the strip to the boat. And progress aft setting the curve with hot glue until it sets. Try to keep it all the glue on the gunnel side of the strip. Once the backbone piece it set rock hard with glue. Lay the next strip on and either screw direct to the first on or clamp and glue. The plan is to laminate up 5 or 6 strips out past the edge. For a more permanent fixture you can put 3 x 4" long putty fillets on the inside of the ply. Once you have it laminated you can now shape the edge using a router/grinder or sander. Once it's close use builders bog/car putty/talc and resin to gap fill. Quick sand and fair it back into the shape you want, then run brown packing tap along the shape. This is the quick mold weapon of choice. Resin won't stick to it. Often it will need to be a series of vertical stripes all the way along to stop the curve causing tape wrinkles. But it definitely will release. Grind a taper on the existing area and lay up 4 layers minimum to hold its shape and let it cure. Grind off the 3 tabs of putty from the inside and peel the mold away.
Yes it sounds like a lot of work. But you are basically recreating a mold like an original boat mold.
If your lucky enough that the curve can be achieved by bending a solid pine batton around you can save some prep work. But the same packing tape method could be used.

The old cap can be reinstalled prior to attempting the gunnel stiffening. I personally pop rivet the flanges using a 50/75mm spacing all the way around. A bit of sikaflex between the flanges before popping the rivets.
That cut up cap would be a nightmare to reinstall if you worked on it upside down to recreate the edges. Too easy to get out of square or shape. Use the hull to stiffen it up before working on reinforcements.


Damo's dodgy boat building factory.

[Keevers88]

Cheers for that Damo, that is the best response I could have hoped for, gonna give it a crack this weekend, cheers mate
Keevers

[Rip it up]

If you have any random questions just ask away. Fibre glassing is easy but the structural aspect is sometimes a black art to master.

Photos help if you need to explain something.


Damo's dodgy boat building factory.

[Keevers88]

Hey Damo,
just an FYI, I layered up the lips of the hull to attach the piece back on and did as you instructed and it turned out schmick. It's solid and the lines match up, looks mint, cheers for that mate. I have a piece of 40 be 40 pine baton, 4m long, caught between a rock and a hard place to get it to bend to the contour of the boat and i'm going to use that as my base for the vertical section of the gunnel. I did some test pieces from 4 layers thick to 7 layers thick; 4 was still a bit flexible and 7 was basically bullet proof so somewhere between 5 and 6 is going to be spot on. Cheers for ya help Damo; good to see there is still someone to help out on here.
Keevers

[Rip it up]

No worries at all keevers, just remember to post some photos.


Damo's dodgy boat building factory.