# 12 ft Grumman v hull mod



## bigjo911 (May 22, 2010)

First Post, first boat and first mod. I have browsed a lot and now it's time for me to load some photos and maybe help some with ideas. Of course I'm looking for any ideas and thoughts you all may have.

"Profit" was dubbed the boats name. I flipped 2 old jon boats for double profit and a old Johnson outboard and was able to buy this Grumman with the profit.

1998 Aluminum Grumman v-hull - Starting from scratch.

Objectives: 

- Add 2 seats
- Mount bow mount troll
- Deck the floors. 




First I wanted to deck the front hull. To stabilize the 1/2in pressure treated plywood I framed some 2x4 and another small piece of plywood.







Than I cut out the hull shape to mount my bow mount trolling motor to. Here, I would like some feed back on how I can securely attach this. My plan is to bolt through the plywood and rim of the boat. 




As I'm writing this my rear seat is being carpeted. This was tricky mounting the seat to the plywood. I had counter sunk SS bolts from under the plywood up through the seat and than nutted. Not to much room to bolt, but it worked.

Here is the rear seat that has the 4 counter sunk ss bolts. In process of carpet. 



Screwing down the carpet. I used small steel 1/2in Phillips screws.


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## bigjo911 (May 22, 2010)

The seats came off my fathers boat. They were kept on his boat for the last 12 years out side. They were covered with seat covers and a 55 gal drum. I shined them up with the vinyl cleaner and they looks nearly new!


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## free jonboat (May 22, 2010)

ok. your REALLY not going to want to here this but pressure treated wood will pitt aluminum and destroy your boat.  so your going to want to get that out asap


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## bigjo911 (May 22, 2010)

Umm, your right. I didn't want to hear that. I had no idea. So marine plywood or regular plywood hu? That really is crappy.


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## Brine (May 22, 2010)

Well, it looks like the boat already has a layer of paint on the inside right? That will certainly help, and if you paint everything that's currently exposed/touching aluminum, I think you'll be fine. The steel screws you used will cause problems before the treated wood. Aluminum doesn't play nice with dissimilar metals. Stainless steel or aluminum is what you want for your fasteners.

Nice looking boat, and those seats (and the story) are awesome.

Good luck with the rest of your build.


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## Sader762 (May 23, 2010)

Regular ply followed by several coats of water sealer then carpet.


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## bigjo911 (May 23, 2010)

I will coat the PT plywood with some extra white exterior paint I have. The boat as mentioned already has a coat of paint from the factory. Has anyone actually experienced degradation of aluminum from PT wood?


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## ober51 (May 23, 2010)

bigjo911 said:


> I will coat the PT plywood with some extra white exterior paint I have. The boat as mentioned already has a coat of paint from the factory. Has anyone actually experienced degradation of aluminum from PT wood?



Saw it big time on a few boats I went to look at - you want to, at minimum, take out the screws and replace with SS hardware, and give a nice liberal coat of paint to the PT wood (if you can't replace). Sorry that it happened, but you'd be more mad if you didn't know and then your profit went downhill fast.


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## bigjo911 (May 24, 2010)

I ended up just painting the PT wood with white exterior paint. I would like to mount the bow troll next, any tips?


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## bassboy1 (May 24, 2010)

Here's a post I did back in 2007, on, ironically, mounting a bow mount to a 12 ft. Grumman Vee.

https://www.tinboats.net/forum/viewtopic.php?f=3&t=334&hilit=bow+mount+trolling


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## bigjo911 (May 25, 2010)

Thanks for the link! Lokos good. Did it hold up well? I saw you mentioned you had plans for improving it. What piece of aluminum is that called? I rather use that method vs drilling holes in my boat.


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## bassboy1 (May 25, 2010)

bigjo911 said:


> Thanks for the link! Lokos good. Did it hold up well? I saw you mentioned you had plans for improving it. What piece of aluminum is that called? I rather use that method vs drilling holes in my boat.



Held up great, up until the point I sold the boat. Don't know if the current owner is using it or not, as I sold the boat and trolling motor separately, but as long as the plywood got painted or varnished or something to protect it from the elements, it should last quite a while. 

Never did improve it. The only issue was that the trolling motor leaned back just slightly, when deployed. I was going to space up the back blocks to level it, but it never happened, and didn't really hinder me much. 

That aluminum is just an odd extrusion. Years back, my dad found a bunch of those at the scrapyard, and bought them all. We use them for making saw fences, as the t - slots give us virtually unlimited hold down options. Coupled with a bucket of varying length 5/16 bolts and other random pieces, they make excellent jigs for fabricating one off parts.

Just about any aluminum extrusion that is solid in the middle would be fine. Solid billet aluminum would work excellently as well.


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## koda (May 26, 2010)

good to know about the PT wood and screws. how about cedar?


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## ennelson7 (Jun 23, 2010)

Have you been able to attach your trolling motor mount yet? I am very interested to see how you did that as I have the same issue.


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## GST65 (Aug 11, 2012)

WOW I did not know that PT wood would eat up Alum. This is some great info and might have saved me a lot of trouble. Thanks


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