Advice on repairing gunwale

[Macintosh]

Hoping folks can offer some advice on what I think (hope) will be a fairly easy repair. Boat is a mid-90’s alumacraft that I had turned upside down on the trailer for winter storage. Had a decent-sized branch blow down and land on the edge of the gunwale—it missed the hull, but bent the gunwale and popped 3 of the rivets connecting it to the hull. I THINK that is the extent of the damage. Photos below.
I believe I can bend the gunwale back down and replace rivets in the original holes plus add a rivet or two and be ok. (??)

Questions I could use advice on:
1) am I missing something else that needs addressed?
2) how would you go about bending the gunwale back into place? There has been some deformation, and while I dont need it to be perfect would like it as structurally sound as possible as well as look as clean as possible. Big clamp between gunwale and the hard chine? Pull the transom corner cap and drive something stiff/straight into the tubing to straighten it? Or??
3) Suggested rivets given this is well above waterline? Id prefer to minimize buying new tools if I can avoid it. I have a pop rivet tool capable of 1/4” rivets. I do not own a compressor. Wondering about the tradeoffs between a solid rivet done with just opposing hammers, and a 1/4”-ish pop-type rivet for this application.

Any other advice, suggestions, etc are also very appreciated. Thanks in advance.

 

[LDUBS]

This is so far outside my expertise I probably shouldn't be responding at all. If nothing else, my post will serve to bump this a little.

I think you say you might be able to bend it down so it is aligned along the top of the gunnel. If you can do that, then taking out the inside and outside "dings" seems like work for a hammer. Maybe some heat? IDK. Remove the seat brace and see if you can bend the gunnel back in line. If it stays, then there is much happiness. Based on the pic's I am not optimistic.

I wonder if it would be better to remove the bent section, straighten it on the work bench, then have someone weld it back on. I would make sure to cut where the gunnel is good, meaning you might be removing two or three feet if I'm reading the pic's correctly. However, I strongly advise you not do this until you hear from someone with more knowledge than me (which is going to be just about everyone).

 

[Macintosh]

Hmm, thanks very much, thats something to ponder. Thats a much more invasive repair than I was going to try. I am not sure the rounded dent in the outside/bottom of the gunwale is going to come out, and Im thinking I’ll probably leave that. If I can clamp the gunwale back so it sits in a straight line I am thinking of simply riveting it back in place and calling it done, at least to try first. I think the crimp in the inwale I can remove in-place, and if I need to replace the pop rivets in the seat brace that’s easy.
I guess I’m asking if that repair outline seems “legit” for a “working” boat that’s pushing 30 years old (as opposed to “half-assed”), and if so what the tradeoffs are in rivet-type to re-attach the gunwale given my available tools.
If it makes any difference, the hull is .065 and the inwale is .080, so .145 total. Looks like they were 3/16 solid rivets originally. I think my choices are 1/4”x 1/8-1/4” grip-length aluminum pop rivets, or 3/16” solid ones (unsure of length needed).

 

[airshot]

I think it is repairable, not to look like new, but to look decent on an old boat !! Easy for me to say because I am a retired toolmaker, working with soft metals for the past 25 years. Go slow, that will be your friend, go fast and it will crack....you dont want that. Getting that dimple out on the outside wont happen, but...it can be improved upon. Adding some heat will definetly help, get it hot slowly, heat needs to soak in, mabey use a big C clamp to try and compact the bulge. A ball pein hammer might also help to stretch the metal slowly. Work on the bulge first, the inner crease will straighten some when the bulge is decreased. Oncevyou get things close to alignment use oversize rivets and buck them in place. If you not familiar with riveting feel free to use SS screws and nuts. I have used them many times when rivets were not availiable. Doesnt look the same, but it works. I would stay away from pop rivets as they are not very heavy duty. For light stress or just holding something in position, they are fine, but in stress areas, there are better things to use. Go slow and take a little at a time and you can get it somewhat close. Good luck and keep us posted !!

 

[thill]

The full repairs of that kind of damage that I've seen involved cutting out the crimped area, flattening out the bent part from the inside and outside and then welding back the removed section with fresh aluminum or the straightened section that had been cut out.

You might want to ask a local body shop if they are interested. Might not cost as much as you think.

 

[Macintosh]

So, before I get into a repair involving cutting and welding, I’m going to try this first. I was able to use several clamps and return the gunwale to perfect alignment. The big dent is still there, but I think I’m going to live with that. At this point a little bit of banging is going to remove the crimps, and I just need to rivet it all back in place.

The damage popped three rivets. I figure I will replace those three, and add four additional ones, in between and on either side of those. So, my question is is a 1/4 inch aluminum pop-rivet sufficient, or do I really want solid rivets? And if so, is it realistic to install the solid rivets using a hammer on one side, and a sledgehammer as a bucking bar on the other side?