'72 Starcraft SS New to me - Looking for design help

[BOAH]

I picked up a 1972 21' SS recently that is just the hull. Everything has been removed so I have a clean slate to work with. The hull itself looks like it is in good shape and pretty clean. I would like to make some pretty big design changes and would like some input.

Starting with the transom, I would like to bring up the back edge so it is straight across and is the same height as the side of the boat. So in other words, I would like to close off the transom if that makes sense. Once that is done, I would then like to install a transom extension with a swim platform for the motor. Lastly, I would like to install a gas tank under the deck.

I've been going through quite a few of the finished boats but am having a hard time piecing all of this together. Can you guide me to any relative threads that would help in my search?

Thanks for your help.

 

[mattsteg]

Based on your description, you have an outboard SS that you want to build up the transom height on? And then put the outboard on a bracket that doubles as a swim platform? If that's the case, I'd look at IOs for structural inspiration, and IO-outboard conversions for the bracket. What you're describing sounds almost like half-converting to IO then converting to outboard with a bracket.

I'm surprised that it doesn't already have a belly tank. There should be plenty of space for one, although the size can be sort of odd. Is your deck off? It should be clearer to see if it is. Watermann's thread on his 18 ft v5ss has good photos of a very nice fuel tank install as well as his quest to source a custom one.

 

[GA_Boater]

Give us a few photos so we can draw ideas on them.

We do have a some bracket conversions in past projects.

FYI - The splashwell is a structural element.

 

[BOAH]

Unfortunately, this is the best that I can do right now for a picture but it will give you an idea of what I've got. So yes, I want to build up the transom to close it off and add an extension for the motor.

The second picture is what I'm imagining.

That's a good idea to look at the IO's to see how they support the transom. And yes, I looked at the tank that Watermann put in and that's exactly what I would like to do. Plenty of more research to do!

Thanks for your input

 

[mattsteg]

Nice clean slate!

 

[Watermann]

I see your 72 SS doesn't have the rib end hull braces. Inspect very closely for and rib end cracks that are forming and consider putting in your own braces to eliminate the other possibility, spray rail chine side splitting.

An OB pod is usually done on the IO boats and it's highly recommended to use a motor with a 25" shaft to get the power head as far from the water as possible. It's not as easy as one thinks to convert to a solid transom with no cut out and as stated the SW adds structure to the stern so it must be accounted for by other means when removing it.

Personally if I were to do this I would add an outer sheet of .090 or .100 AL over the existing AL and add an inner piece of AL that fits in the cut out to make it flush rather than removing the existing and replacing with new..

 

[SHSU]

Personally if I were to do this I would add an outer sheet of .090 or .100 AL over the existing AL and add an inner piece of AL that fits in the cut out to make it flush rather than removing the existing and replacing with new..

Is the extra aluminum needed? I would think the "skin" is just to make it water tight. So beefing up the transom wood/brackets/supports would be the answer for structural support.

Am I misunderstanding your thought process?

SHSU

 

[mattsteg]

Is the extra aluminum needed? I would think the "skin" is just to make it water tight. So beefing up the transom wood/brackets/supports would be the answer for structural support.

Am I misunderstanding your thought process?

SHSU

My read is that it's a lot easier to add an additional skin to the outside of the boat, then rip out the old and put in a new. And if you want the inside flush, then the easiest way to get this is to put in another inner layer in the cutout.

 

[Watermann]

Is the extra aluminum needed? I would think the "skin" is just to make it water tight. So beefing up the transom wood/brackets/supports would be the answer for structural support.

Am I misunderstanding your thought process?

SHSU

Problem I'd have with just filling in the cut-out is that over time that seam could be a source of leaking but not with an outer skin covering that entire seam with a construction tube of 5200 buttered up between them.

 

[mattsteg]

Problem I'd have with just filling in the cut-out is that over time that seam could be a source of leaking but not with an outer skin covering that entire seam with a construction tube of 5200 buttered up between them.

Leaks are bad enough, but hidden leaks next to a wood structural member are not fun.

 

[SHSU]

Problem I'd have with just filling in the cut-out is that over time that seam could be a source of leaking but not with an outer skin covering that entire seam with a construction tube of 5200 buttered up between them.

Ah, got it. Not necessarily structural but water tight with 5200.

SHSU

 

[El Gaffer]

Mine was already a I/O, but I did put a additional skin on the outside to cover the out drive hole. I did use entire tube of 5200. I put a belly tank in to. I will get a few photos later of it

 

[Mkline85]

I raised mt transom, and put a bracket on. I should hopefully get it back next week. I plan to ad support on the inside of the transom.

 

[BOAH]

Yes, that is it! I would love to see more pictures and exactly what you did on both of those!

 

[Mkline85]

Its still at the fabricator. He has a paint shop as well and is gonna paint the hull this week. Hopefully I will pick it up next week and figure out what extra supports ill add inside the transom.

 

[El Gaffer]

Here are a few more shots of mine. I fit it all, then have since removed everything to apply gluvit and vacuum up metal shaving from drilling rivet holes. I have also wired wheeled all aluminum to make it dull, with a stainless wheel. All bolts through bracket were coated in 5200.
Sorry, I find posting full size photos hard here.

 

[BOAH]

Nice job! I think that transom will hold!

 

[BOAH]

I've decided that I'm not going to undertake this one and instead I'm going to sell it. If I'm selling it as is, what do you think is a fair price to ask?

 

[Watermann]

I've decided that I'm not going to undertake this one and instead I'm going to sell it. If I'm selling it as is, what do you think is a fair price to ask?

We don't act as a buy and sell forum as far as prices and such. Very location specific and since you have nothing into it sell for what you paid.

 

[BOAH]

Fair enough. Thanks!