Are Metal Boats and Salt Water a bad mix?

[Techtraveler]

Trying to find a smaller (15-19")used boat and have seen a few metal boats that look interesting. I will be using it 100% in Salt Water and it will live outside on a very small portion of an island between the ocean and Intercostal. Will this be a rust issue in no time? I have seen a Polar Kraft that looks nice.

 

[WIMUSKY]

Re: Are Metal Boats and Salt Water a bad mix?

Aluminum doesn't rust.....

 

[kfa4303]

Re: Are Metal Boats and Salt Water a bad mix?

+1. Aluminum is fine. I run a tinny down here in FL myself. However, if you're going to leave the hull in saltwater for extended periods of time you will need to attach a sacrificial Zinc anode below the waterline. You will also need to "marinize" your boat by switching any and all hardware to 316 stainless steel to avoid rust. Be sure to hose your boat, and trailer down very well with fresh water afterwards and run your motor on muffs/test tank using fresh water for several minutes to flush any salt out of the system.

 

[Techtraveler]

Re: Are Metal Boats and Salt Water a bad mix?

Boat won't stay in the water more then 2 days at a time. We have a hose right at our ramp for washing.

 

[Home Cookin']

Re: Are Metal Boats and Salt Water a bad mix?

the navy doesn't think so.

Your using the boat 2 days at a time won't hurt it; what will eventually get to it is the salt air--and not much you cna do about it; just part of living on the coast. There is a balance between covering stuff and trapping moisure and leaving it exposed where it can also dry. And rain water is your friend.


If you have a battery, disconnect it (use a battery switch) when not in use to prevent "leakage." Protect parts with white lithium grease. Don't use WD40.

Your trailer will take it harder than the boat. Try to launch and retrieve your boat without sinking it below the axle/hubs. There are many techniques for this and your trailer will last if you do, die if you don't.

 

[dingbat]

Re: Are Metal Boats and Salt Water a bad mix?

the navy doesn't think so.

They certainly have second thoughts......
U.S. Navy’s “Brand New” Aluminum Ship: Foiled by Seawater | TIME.com

 

[NSBCraig]

Re: Are Metal Boats and Salt Water a bad mix?

Aluminum is fine in salt water. So the navy is having issues with their paint not protecting a new boat. Probably new paint too.

Broward yachts has been build custom yachts 80' and up for ever out of aluminum and none of their owners are complaining.

 

[minuteman62-64]

Re: Are Metal Boats and Salt Water a bad mix?

Lots of trailered aluminum boats here in San Diego that have seen nothing but salt water for many years (mine is an '82). The common denominator in longevity, as noted above, seems to be reasonable care and lots of fresh water flushing.

For the trailer, galvanized, with ss fastenings, seems to be the medium of choice here. Good luck with launching w/o submerging your trailer wheels (doesn't work for me, anyways ) - if the frame is galvanized, at worst you are looking at every 5-10 years replacing your hubs and springs - not a huge project.

 

[kfa4303]

Re: Are Metal Boats and Salt Water a bad mix?

+1. I know lots of folks here in FL, where the water is particularly salty, that just sort of resign themselves to having to get another, slightly used, trailer every few years. Despite your best efforts, the ocean will always win in the end. Thankfully, there are millions on C-list for pretty cheap. Of course nice, all-aluminum models are ideal, but they often cost more than the boats they tend to carry in my part of FL.

 

[dingbat]

Re: Are Metal Boats and Salt Water a bad mix?

So the navy is having issues with their paint not protecting a new boat. P

Where is you come up with that? No paint is going to solve galvanic corrosion

Corrosion is a $23-billion-a-year problem in the equipment-heavy U.S. military. But Independence?s decay isn?t a case of mere oxidation, which can usually be prevented by careful maintenance and cleaning. No, the 418-foot-long warship is dissolving due to one whopper of a design flaw.

There are technical terms for this kind of disintegration. Austal USA, Independence?s Alabama-based builder, calls it ?galvanic corrosion.? Civilian scientists know it as ?electrolysis.? It?s what occurs when ?two dissimilar metals, after being in electrical contact with one another, corrode at different rates,? Austal explained in a statement.
?That suggests to me the metal is completely gone, not rusted,? naval analyst Raymond Pritchett wrote of Independence?s problem.

Independence?s corrosion is concentrated in her water jets ? shipboard versions of airplane engines ? where steel ?impeller housings? come in contact with the surrounding aluminum structure. Electrical charges possibly originating in the ship?s combat systems apparently sparked the electrolysis.

 

[NSBCraig]

Re: Are Metal Boats and Salt Water a bad mix?

From the fact that there are so many large aluminum yachts not corroding.

What stops it? Well my guess would be paint and anodes. What do you think?

Lots of them have water jet drives too and again they are not having a problem. I'll give you Moonraker as an example, a boat I've done work on and had a five year business relationship with as the boats powdercoater. We (the captain, engineer and I) had many conversations about the condition of the boat, all the way down to the anchor (which I powdercoated with some crazy nylon powder that required a reverse voltage gun and it's overall performance sucked, but then we were doing test for Pratt and Lambert on a new product). None of the underwater parts were corroding at any rate worse then being the same maintenance you have to do on a 100'+ boat.

It took Hatteras to break the 100+ make out of fiberglass, besides that they have been made of aluminum since the 80's.

Houseboats and pontoon boats sit in saltwater only hoping to get pulled out for maintenance once a year. Yet the metal is still there.

Why do they not suffer the same fate as these couple navy boats?

So they are having problems how does this affect the OP and his wanting to buy a boat anyway?