Adding Chine Bracing on a '75 18' Starcraft SS

[classiccat]

Howdy Folks! I'm in the early stages of a Resto on a '75 18' Starcraft SS.

My home water is a big tidal river (Hudson) that puts a beating on a hull; if there is a weak-point in the hull construction (chine cracks are pretty common), i guarantee that it will show after a season or 2; North/South wind fighting a pretty strong tide produces some major waveage!

My plan is to connect to the exiting side/lower hull overlap...drilling-out the existing rivets (carefully not to expand the existing holes) and tie the side/bottom hull pieces with aluminum using solid Rivets.

My question for you guys is: do you think the placement of these braces and do you foresee any unwanted side-effects (i.e. like stress cracks in the bottom hull sheet?)



Nevermind the antifouling epoxy & stray blind rivets from the PO...i'm in the process of cleaning-up that mess. :facepalm:

 

[jbcurt00]

Re: Adding Chine Bracing on a '75 18' Starcraft SS

You might want to give Grandad's thread a read. I'm not an SC ENGINEER, but I think your proposed riveted braces are BETWEEN the areas that 'typically' crack on some of the larger SC's. Granddad used similar styled plates UNDER the rib ends, which if those areas are prone to cracks, braces between them, might make those cracks worse or even more likely to occur.

Some of the other SC resto's also discuss the rib end cracking and adding plates similar to Grandad's but some had them already from SC.....

Magnumdeke's Islander:

Magnumdekes 1976 22' Starcraft Islander

 

[GA_Boater]

Re: Adding Chine Bracing on a '75 18' Starcraft SS

We just had a talk about this in Barato2's Holiday thread a few weeks ago. A few pics there also. DozerII's thread has some good pics too. The factory gussets are at the end of the ribs. You drew them right, just go in between the ribs. Without structural analysis, I think the bottom of the hull flexes and the force ends up from the ribs to the chine causing the chine to crack. A little bit of SWAGing in that statement.

I don't know how common the chine cracks are, but SC must have thought something had to be done.

 

[NoSkillz]

Re: Adding Chine Bracing on a '75 18' Starcraft SS

I love bucking rivets! Watching op2:

 

[GA_Boater]

Re: Adding Chine Bracing on a '75 18' Starcraft SS

I love bucking rivets! Watching op2:

Better than itching. op2:

 

[classiccat]

Re: Adding Chine Bracing on a '75 18' Starcraft SS

Thanks for the feedback guys! this is really helpful.

I can kill 3 birds (maybe more!) with 1 stone by putting them Under the ribs...prevent not only chine cracking but also rib and skin cracking as well.

They didn't make it easy for me...several of the SB rib ends are snug-up against the overlap/seam. I'll have to drill-out additional rivets in the ribs in order to lift the ends and remove some rib-tab material (I'm in no hurry).

@NoSkillz: air riveting hammer I've never used it before but I do have a splashwell that needs some tough-love...good practice.

 

[magnumdeke]

Re: Adding Chine Bracing on a '75 18' Starcraft SS

Jb's oics up there are actually from my 69 thread, the 1976 has factory bracing the length of the chine like you want to do with a bend in it to go under the rib ends and cover the rivet holes, gets riveted from underneath and the side.
Ol 69 ended up in the back of my truck due to the damage!

Factory brace by Cody's left hand

 

[GA_Boater]

Re: Adding Chine Bracing on a '75 18' Starcraft SS

Blue - You'll be an accomplished riveter when you finish this. :thumb:

 

[classiccat]

Re: Adding Chine Bracing on a '75 18' Starcraft SS

Jb's oics up there are actually from my 69 thread, the 1976 has factory bracing the length of the chine like you want to do with a bend in it to go under the rib ends and cover the rivet holes, gets riveted from underneath and the side.
Ol 69 ended up in the back of my truck due to the damage!

I read that '69 thread and was unaware of her impending doom...turn-the-page and :lol:

Blue - You'll be an accomplished riveter when you finish this. :thumb:

assuming that I find someone willing to crawl underneath (in June/July) and hold the bucking bar for several hours...that should cost me AT LEAST 1 case of "wobbly" :lol:

 

[jbcurt00]

Re: Adding Chine Bracing on a '75 18' Starcraft SS

Up the wobbly pop offer w/ a TAKE THEM HOME set of ear protection