Used Salt Water Aluminum Boat?

[Knot Sure]

What should I look for in an aluminum boat that has been used in salt water.  A boat that was (suposedly) designed for salt water and the motor.  I understand that salt water shortens the life of the motor.  By how much?  The boat has been stored on a trailer.  Is there any where to look on the boat or motor for corrosion or other problems.  The trailer?

[fishinwrench]

Until you partially disassemble the outboard then you'll never know. 

Will the lower unit come off?   If not then it's only good until the water pump needs replaced.  

Will the lower unit bearing carrier come out?    If not then the motor is only good until the propshaft seal fails. 

Will the flywheel come off?   If not then it's only good until a stator or timer base/trigger needs replaced. 

Can you remove the thermostat housing? .......  

I think you get the idea now 🙂 

Mercury, Suzuki and Yamaha only expect them to last 5-7 years in saltwater, so know THAT. 

[Knot Sure]

OK, thanks.  So that tells me they are disposable across the board. The salt is just too hard on the metals. So, I;m thinking an aluminum boat is also strongly susceptible to corrosion that you would not see in a fresh water only boat. 

[tjm]

21 minutes ago, Knot Sure said:

So, I;m thinking an aluminum boat is also strongly susceptible to corrosion that you would not see in a fresh water only boat. 

Know nothing about boats, but 50+ years ago the USN used a lot of aluminum on ships' superstructure. I doubt they'd do that if the salt exposure  was a problem. My experience is that as long as aluminum stays "painted" (coated) it doesn't seem to corrode at all, never had corrosion run wild under the paint like it does on steel. "Unpainted" aluminum corrodes in average air because it loves oxygen, and from what I saw the salt doesn't seem to make that any worse.  I've read that the white powdery aluminum oxide  corrosion makes it's own seal that prevents further corrosion. I'd look for fractures, scratches, gouges, pitting ect. in the aluminum and I'd walk away from anything that looked like a recent paint job.

[Knot Sure]

I am told that the boat of choice in the northwestern pacific states  and Alaska is often an aluminum boat, being used in coastal (salt) water and also in the rivers.   And the rocks are the deciding reason.  I'm thinking, ozark rocks are as difficult as northwestern rocks. So, that is what lead me down this path. 

[jdmidwest]

Aluminum boats will be the same 30 years from now.  Fiberglass ones will be faded, cracked, and falling apart unless babied and kept under cover.

Aluminum boats are tough and can be painted when they fade.  Saltwater should not affect the boat any, its the damage to other components like the motor.