SWIM PLATFORM WITH A BARE 6061 T6 ALUMINUM FRAME Compatible w/ salt water?

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Capn Craig

Oct 16, 2010
Several years ago I built a welded*aluminum frame swim platform for my Trojan F26 cruiser.* It has a 3/4" Starboard top surface with white vinyl dock edging on the edges.* From above, you can not see the aluminum sub frame.* The dock edging proved to be a great idea as there is no chance of scuffing small boats tied to it.* The starboard does discolor some with dirt, but cleans up nicely with a big pressure washer.* It is roughly 3' "wide" by 8' long.* The extra width makes it very usefull as a dingy dock, and swim place.

The swim platform that came with my Californian 34 LRC is hardly 2' wide.* With the outward slope of the transom, there is hardly enough room to turn around without holding on to the aft rail to aviod bumping your hind end against the transom and falling off.* I am not a little guy.

Since I'm parting out the Trojan, I'm thinking of adapting the swim step I built to the Californian.* The Californian is a bit over 2' wider than the Trojan.* Both boats have a curved transom that appears to be close to the same radius.* What I'm thinking, is to cut the swim platform in half, and add about 2' to the center.**By*doing that I could best fit the radius of each half to the transom,* by being shorter any mismatch in radius would not be near as noticeable.* I would weld the new center section to what ever angles and radius needed to fit.* I would cover with*starboard and cover the seams with stainless strips or something else then replace all the dock edging with new to hide the joints.

I have no salt water experience, but intend to take the Californian there in a few years.* What is your opinion on bare 6061 aluminum alloy in salt?* I had a conversation with a guy in the aluminum extrusion industry earlier this week.* He said he just got done with a project building a marina in N. Carolina with* 6063 aluminum framed docks.* He said i would probably get 'white rust' but since the frame is hidden from view, this would pose no problem.* The swim platform would be 8 or 9 inches out of the water, except for the lower supports

What do you think?**


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Capn Craig* - this summer in the PNW I have seen many all Al boats with swim platforms of, naturally, Al.* Any non Al fasteners you'd use may*yield*the biggest headache in salt water.
Scout had all aluminum platform which I removed, sand blasted, welded on brackets for swim ladder*and had powder coated. As you see it has not been re-installed. Not sure what aluminum it is but it's heavy and hard. I'm 225# and there was no flex in it when I stood on it with Julie (?#). I'm hoping the powder coating holds up for a few years.


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Anodize. 6061T6 is what ultralight aircraft are built of. And almost all have the aluminum frames anodized. Anodized AND powder coated would probably be even better. Another coating that may work well is POR-15. It's UV sensitive and must be top coated. The usual top coat is Chassis Coat (also made by POR-15). I just finished my oil tank at home w POR-15 and Chassis Coat. It brushes just fine especially the 1st coat of POR-15.
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