1966 Starcraft SunChief / hull strength questions

[LakeSaintClair]

I have purchased a 1966 StarCraft Sunchief 22 foot outboard boat. I hope to restore it to its close to original condition as possible. I also plan to rebuild the transom and flooring.

When I purchased it, the floor had already been removed, and was impressed with the fact that it appeared very clean in the bilge area. The chine rivets and ribs appear to be in good shape. The hull appears only to have been used in fresh water, as there are no signs of corrosion. Initially, I felt very inspired to take this boat back to a complete restoration. I have some hesitations now after reading about some possible weaknesses of older Starcraft hulls.

My questions...

1). Since I found this forum, I have read about older StarCraft’s having chine cracking issues, due to ribs that didn’t overlap onto the chine seam. How much should I be concerned about this? Is there a modification that can be done to strengthen this area?

2). The boat was originally rated for 120 hp. I have a set of Johnson 70 hp outboards. Each of them weigh approximately 260 pounds. Would I be overloading the old girl if I hung the pair on the transom? I am very judicious when it comes to speed and throttle use, and would likely never run it at top end. I’m more concerned about 520 pounds of outboard hanging on the back...

Any insight you might have would be very welcome. Thank you!

 

[LakeSaintClair]

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[LakeSaintClair]

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[LakeSaintClair]

The hull has three large transom knees for transom / motor support. I also included some pictures of the rib to chine unions, as well as one of the two prospective motors I’d like to put on it.

Another question… If you think two motors would be too heavy for the boat, how do you think a single 70 horse would push that boat?

 

[classiccat]

Welcome and congrats on a clean template! Did you perform a leak test?

People hang kickers along with the V4 powerplant on there all of the time and don't seem to have issues. Probably a similar cumulative weight as 2 3cyl loopers.

Regarding the structural concern, i'll share my personal experience.

I didn't have a cracked spray rail however my outer chine was roached leading to stress cracks at the 1st set of rib-end rivets.

Starcraft relied on the integrity of the wood deck and side panels to reinforce the area.

As-is

Add risers

then add the reinforcement.

Then this bottom bracket adds additional reinforcement:

I think alot of the chine / spray rail damage occur during trailering... As well as how the boat is strapped down to the trailer. I'd avoid using a strap over the gunnels and wrenching it down; use the bow eyes.

 

[LakeSaintClair]

Wow classiccat, thank you very much for the detailed explaination!!! Your Diagrams gave the best explanation I’ve seen so far. What you say makes a lot of sense. I like how you reinforced the hull. Those gussets you made are pretty straightforward. Thanks for your input!

On your restoration, did you re-install the original sides, or did you rely on your custom gussets to reinforce the hull at the chine?

 

[classiccat]

Wow classiccat, thank you very much for the detailed explaination!!! Your Diagrams gave the best explanation I’ve seen so far. What you say makes a lot of sense. I like how you reinforced the hull. Those gussets you made are pretty straightforward. Thanks for your input!

On your restoration, did you re-install the original sides, or did you rely on your custom gussets to reinforce the hull at the chine?

No problem! Thank you for thinking critically about the issue!

I found 1 typo on the trailering recommendations...I meant Stern eye's (not bow eyes).

Yes, I'll be installing fiberglass reinforced side panels.

 

[Watermann]

Adding hull braces has been done by a few of us by adding them between the ribs rather than under them as the factory started doing later in the 1970's. Reason being is the ribs are not bent to accommodate the brace thickness. Having the braces under the rib of course limit the 2nd problem, rib end cracks but with new deck, side panels and the braces the rib end crack problem may well be eliminated.