Stainless Steel Pontoons for Houseboat

I purchased a freshwater houseboat that has old fiberglass over wood pontoons that need replacing.

Multiple local fabricators are pushing 304 Stainless Steel pontoons as a replacement. From everything that I have read, this is a bad material as it will cause galvanic corrosion on my Aluminum outdrive. I feel like aluminum is the better option, but fabricators are resistant to it due to some recent failures on local boats. The houseboat frame is mild Steel.

Any thoughts on this from this community? Just manage the corrosion with anodes?

Here are some boat details:
48k lbs
50x20
Steel Frame
Currently has 3 - 50' L x 4' W x 2' tall pontoons
Mercruiser stern drive 3.0 / Alpha 1. Engine bay in rear middle pontoon
Moored on a ball, no shore power connected

 

Welcome to the forum Paticus

I would never sue 304 S/S for anything other than interior fittings.
304 is not a marine grade S/S.

Aluminium is way way better.
The failures they cite, I suspect are more likely owing to fabricators not adhering to the more strict method and procedures for fabricating aluminium.
In simple terms a steel welder cannot weld aluminium. They think they can but the procedures and methodology is totally different, and when under pressure of lacking info on the dwgs, they use the "steel play book" of fabrication. Wrong!.

Thus better to get a dedicated aluminium fabricator...and then make sure the details are designed correctly.

 

Ad Hoc is of course correct.

Have you considered encapsulated foam.
Standard and custom sizing.
Surely somebody is doing it in your neighbourhood you could get a quote.

 

Another thought, how old is the boat ? I would cost out new ply/fibreglass pontoons as you get a quote for aluminium.
Ply/Epoxy will probably last another 20 years, especially if you use Epoxy rather than Polyester.
Its not just the material, its the cost of fabrication. You might know a couple of handymen who could do a good job of glassing Plywood, but welders are never cheap.

 

Okay, yea the stainless preference in the area is super odd right? And 304?? I will try to push for Aluminum and vette the fabricator.

These foam filled Poly pontoons look pretty interesting… I’m going to call some manufacturers next week and get some more details. I like that they are low maintenance, no galvanization issues, and can be replaced modularly. I wonder why more folks don’t use them?

Example: 36-inch Diameter Pontoons – Plastic Pontoon https://plasticpontoon.com/36-inch-diameter-pontoons/

 

Thats odd, as my understanding was that aluminum boat building was popular in the pacific northwest. It seemed to be a trusted building material in that area.

 

Cali isn't really the pacific nw, and I'm guessing this is inland. Fished a winter in Central and Southern California, was a bit amazed at almost non existent marine tradesman for large amounts of coast. Boat owner was born and raised and in his early 60s, owned an aluminum boat for almost 20 years. We had an issue and he spent almost 2x days looking for someone to do the work.... out solution was 8k in welding gear and me fixing it.

Most shops should have aluminum capacity, it's not a hyper specialized methodology like ti. Aluminum supply chain has had a myriad of disruptions the last half a decade, more bad plate has snuck out than should have. Can understand a shops hesitancy on that. Not much fun cutting out 3 year old bad plate.

That said 304 would probably not be a good choice either.

The foam filled poly seems like a good fit.

 

I agree that poly is worth looking into.

If round pontoons work, there are aluminum fabricators that can make them to spec and ship them. The pontoon boat industry drove that market. Its pretty easy to make round pontoons if you have the equipment to roll sheet metal.

I wonder if stray current at a local marina is causing the problem. Someone should investigate for safety reasons.

 

Totally agree.

I’m also hitting up some Aluminum fabrication shops in the area to see if they have experience with toons.

Roamer Marine gave me a good quote, I wish they were closer so they could install as well. Not trying to play general contractor with separate fabricators, installers, shipper, etc. Roamer Marine Inc. https://roamermarine.com/?gclid=CjwKCAjwpJWoBhA8EiwAHZFzfn60TISc8HZRRpEgS2Y6OIoex6cnficpbuI0zKFntzw6cg4GniMyBxoCgHgQAvD_BwE

 

There is a very skilled alloy guy just over the Oregon border in coos Bay. While still a jaunt depending on what part of California the house boat is, it's closer than Indiana. Tarheel boats has done some work for acquaintances up here and it's very well done. I'd not doubt there capacity to draw up and fabricate an aluminum pontoon or three.

Would think the standard sized poly and foam would be cheaper, faster and oddly enough a better choice.

 

Just by chance, I came across this Poly system, Pontoons in Boxes. He didn't give a price, so let us all know if you look it up

 

With reference to Ray's Youtube link above, I think that these are the manufacturers of the pontoons - Plastic Pontoon https://plasticpontoon.com/

 

He verbally said pontoon warehouse, they have a download able pdf with prices for the 25 and 27 inch diameter setups. Have no earthly idea how to post it with my phone but downloaded it.

 

I will say.. the 304 stainless might be a good choice for freshwater. Everything that calls for 316, calls for it for marine/salt environments.

I would provide great tensile strength over Aluminum. I still have the issue of galvanization with the aluminum drive though. Not sure if there are enough anodes in the world to combat against big *** SS pontoons, with that little outdrive.

 

Are you in fresh or salt water? And were the local aluminum boats with failures in fresh or salt water?