Alum. stringers detached from hull

[Brimauster]

As you know, I have had my eye on an '81 Starcraft SS 18' for a while and I went back today and looked a little deeper and found something that made my heart sink... It appears that the stringers running fore and aft have pulled away from the hull ribs, pulling the rivets through the metal. The stringers have two rivets per rib, and all were pulled out, leaving the bucked end in the rib and empty holes in the stringer. Other than pulling all the ribs out, there is no way to get to the under side of the ribs to buck new rivets. Blind rivets will work, but I'd have to drill out a LOT of rivets first.

As a repair solution, I was thinking that once the hull is gutted, I could use a bent alum. bracket on each side of the stringer, riveted to the ribs (blind, solid, of course)and then bolted through the stringer. The holes in the stringer are in okay shape, not ripped or anything, but the metal is kind of thin. Or, could I just simply move the stringer outward another inch, drill new holes in the ribs, and use blind rivets to re-attach the stringer? Would this compromise the hull strength in any way? Should I try to repair it, or keep looking for a boat in better shape? The rest of the boat is good, but this new discovery might well spell doom for me. What would YOU do?

 

[reelfishin]

Re: Alum. stringers detached from hull

Whether or not I would buy the boat or not would greatly depend on the price.
Anything can be fixed. Myself, I'd weld them in right back where they were. That way you don't affect the height for floor installation.
I have two older Starcraft aluminum boats, both have many rounded looking aluminum ribs with 3 'Z' shaped aluminum stringers run laterally. There is also a few straps that bridge the gaps between plywood sheets. Both of mine had a few rivets pulled from the stringers being bent over due to rotted wood and people walking on them without the support of the wood to tie them together.

I had one rib that actually cracked where the rivet was, it was broke in two pieces, it cracked clean in two but was still secured to the hull skin with the outer rivets. I simply welded the crack and any other suspect areas. I don't expect it to ever be a problem again, at least not in my lifetime anyhow.

I have not had the bottom open on any of the later models, but I suspect that they are similar? Both of mine are the style hull with the wide front keel plate.

 

[Brimauster]

Re: Alum. stringers detached from hull

Thanks for the reply!... The price is 1600 with a sad, rusty old Johnson 140, or- 1200 with no motor. The rest of the boat looks okay, some minor stuff here and there, but the separated stringers bothers me... What caused them to separate? Will it happen again? I'll have to remove the stringers completely, remove all the pulled rivets from the ribs, and re-install the stringers using blind rivets. I'd also use an angled alum channel on the top of the stringers' lower "leg", sandwiching the stringer. I attached a 3-D image below to illustrate. The red "Backing plate would run the full length of the stringer to add strength. What'cha think?

 

[tashasdaddy]

Re: Alum. stringers detached from hull

i do a lot of restoration, my opinion, pass on it. for 1600, you will find something better. he obviously know the motor is of no value. the trailer may be $300, and the hull at present is worth the recycle value of the aluminum.