1974 Starcraft Mariner 16 floor and transom replacement help

[bwingler57]

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Ok got the motor off the boat today, since no one was around went and got a 2.5 ton come along at tractor supply. Had no problem pulling the motor off and putting it on my motor stand. Now to get the inside of the boat good and clean so i can seal the seams with gluvit and get a dang hole patched. Transom is a mess as well, you can see the twist in the transom wood. It may be more work then the floor. Guess it is time to learn how to braze aluminum lol. Also Watermann i added two pictures of the power trim unit

 

[Watermann]

I see, yeah I had a similar unit on my 55 before I put the CMC on. That side pump will only tilt the motor for trailering, it won't trim it when under power.

 

[bwingler57]

No Title

Today i cleaned out the bottom of the boat and pressure washed it to see if there was more damage. After i get the hole patched i will do the water test to check for leaks. Next i will remove the transom wood. Also i was wondering if i didn't put the bench seats back in would that weaken the boat hull?

 

[Watermann]

Yeah the bench seats do provide structure for the hull but that can be overcome with some modifications that add to the structure. Things like side panels, raised casting decks, rod lockers and storage boxes can be added that tie the sides in but all at the cost of weight and expense to the build.

 

[macsmith777]

I am thrilled to see this project, as I am going to pick up the exact same boat in about 3 hours. I will begin my own thread with pics shortly. Good luck and I am looking forward to comparing our projects!

 

[bwingler57]

I am thrilled to see this project, as I am going to pick up the exact same boat in about 3 hours. I will begin my own thread with pics shortly. Good luck and I am looking forward to comparing our projects!

That is awesome!! Make sure you give me the link to your build so i can follow along also. And post lots of pictures

 

[bwingler57]

Well all just got back from the fishing trip, Seen a lot of salmon but could not get a bite to save my life, Got skunked!!

Next time i go i will have my boat!!

 

[macsmith777]

Hey 57, I think this is the link. I am looking at the transom, and even with the caps off, it seems boxed in by the metal on the gunwale. Does yours seem the same? It just appears that one must bend metal to get it out...

 

[bwingler57]

Hey Mac, i will let you know on that i will be starting to remove my transom tomorrow, Mine is warped and twisted, so I'm sure it is going to be a pain lol

 

[bwingler57]

No Title

More Damage found after i started taking everything off the transom, First is the knee brace, from the top down on both sides it is broke off 3 holes down, next is the floor support on the port side is broke, Next the transom is bent pretty good. You can see it all in the pictures.

#1. Can the transom aluminum be reshaped without stressing the metal?
#2. What do i do about the knee brace? Even tho the boat is rated for 50hp do you think the motor broke it?
#3..To take the transom wood out i should i just cut the gunnel trim because the transom caps would cover it there or should i remove the rivets and slide it out, both sides are the same, you can see the details in the pictures.
#4. I will read up on Watermann sticky about riveting as i see i got several to replace and tighten up on the transom,

All suggestions are welcome as i am stuck now on my next move.

 

[Watermann]

Yeah the transom was bowed out I'd say by the motor due to lack of integrity of the wood and no knee brace. (This is not that bad really)The new transom wood should take that bow out but you may have to spread the sides out just a little if they've been drawn in because of the bow in the transom, maybe using a load lock or something similar that can remain in place while you do the work.

To remove the transom. Personally I would remove the rubrails, trim and then gunnels to replace the old loose blind rivets, it's amazing how tight it makes the boat after replacing those blinds under the RR. The transom wood will then be at your mercy.

There's a number of guys here that have repaired their knee braces using angle AL. If you're planning on getting into solid riveting then remove the knee brace altogether so it can be cleaned underneath, repaired and go back in with brand new rivets.

 

[macsmith777]

I see what you mean 57. those last couple pics where the gunnel covers the end of the transom on each side has me flummoxed. How to remove without either removing a ton of rivets or bending the aluminum.

 

[DirtyHarry83]

Yeah, I get what you mean Macsmith777. Starcraft decided to make the boat/transom and then add the gunnels. For my two cents Harbor Freight has a air powered rivet gun. I use that thing for my rivets. Just make sure the rivets purchased are all aluminum. They can be purchased online or in a pinch Home Depot sells some from Dewalt.

 

[bwingler57]

No Title

I was surprised how easy it was to remove the transom, As twisted and bent as the transom wood was i could make an airplane propeller out of it lol.
I had to drill out one rivet at the end of the rub rail insert on each side then pull the insert out, under that was several machine screws with nuts that had to be removed to open it up enough to get to all the inside rivets on the gunnel top cover.

Next there was a bunch of rivets that had to be drilled out on both sides of the gunnel covers as you can see in the pictures.

Next i used a piece of tie wire to keep the inside trim cover off of the transom.

Next i gently pried up on the transom wood working from both sides and up it came. Lifted it on out.

Now to pick up a sheet of 3/4' plywood to make a new transom, it is 1 1/2' thick.

 

[Decker83]

You did a great job on getting out that transom wood. :thumb:

 

[macsmith777]

Looks great! Man, I was hoping not have to deconstruct so much to get that transom out, but so it goes. On the bright side, I found a local welder who will repair all my screw holes, repair the knee brace, and bolster the stern as needed for about 75 bucks all in. What are you planning on using for the floor, 1/2, 5/8?

 

[bwingler57]

You did a great job on getting out that transom wood. :thumb:

Thank you Decker

 

[bwingler57]

Looks great! Man, I was hoping not have to deconstruct so much to get that transom out, but so it goes. On the bright side, I found a local welder who will repair all my screw holes, repair the knee brace, and bolster the stern as needed for about 75 bucks all in. What are you planning on using for the floor, 1/2, 5/8?

Hey Mac, Yeah it took some tear down but it really wasn't that bad, it took about 90 minutes to do it and get the transom out. As far as getting a welder becareful about that, i talked to one on the phone then took the boat over to him and after he seen the hole and where it was he told me welding that close to seams and rivets can cause leaks from the aluminum being heated up while welding. I elected not to because of that. I am going to just do a patch then water test the boat with a garden hose and buck any rivets that leak. As far as the floor goes, i am going to use 1/2" and reinforce where the seat bases will be. Menard's has a 1/2'x5 x 8 plywood and the floor will only have one seam using it.

 

[macsmith777]

Nice! I asked around, and so far can only find 4' ply. Thanks for the heads up. The welder said the same to me about seams leaking. fortunately, as far as I know so far, all the little repairs are above water line. Just holes from removed screws in the decking etc. The knee brace repairs are up near the very top, so no worries there. Thus far I have only found 1 leak in the hull when cleaning it out, we shall see when I fill it with water.. I think gluvit will handle the one I found as it appears to be quite small. Thanks for the heads up on everything, your project is moving right along!

 

[macsmith777]

Are you using marine grade for the transom, or ACX? Marine 3/4" here is 120 a sheet (ouch!). I may just go ACX if that works..