Aluminum Boats & Salt...

[FloridaFishinFool]

Boat as new as shown in a sales brochure. And it is clear from this photo that at least the inside of this boat was painted providing some protection...
9


I post this as an FYI because there seems to be differing opinions on whether aluminum boats should be used in saltwater. Some say yes, and some say no.

It is OK to use aluminum boats in saltwater as long as the aluminum remains intact, but once galvanic and electrolysis corrosion begins, there is no cure. The boat is on a countdown to the scrapyard.

What I am about to show you is an AlumaCraft hull I was given several years ago for free and it soon became clear why the hull was free... and worthless as a boat any longer.

Bottom line, this aluminum boat spent its life in saltwater. It had been stripped down and re-outfitted like a flats boat with polling platform, installed live well, and other stuff.

I tore into the transom where some of the leaks were and I found salt crystals a quarter of an inch thick just eating away at the hull... rinsing did not help this boat!

Here I am tearing into the transom. I gotta get that wood out of there. If this hull were repairable, I was going to replace the wood with plastic...





***All the white stuff you see in these images is dried salt crystals some darn near 1/4" thick.



Once the wood was removed, wet salt was all over the hull underneath the wood:



Down in the bottom seam of the boat where paint was suppose to protect the hull:



This corrosion was under the transom knee:



Bottom line here to all of this corrosion is that it is NOT caused from dissimilar metals. There are no dissimilar metals around these salt locations... now take a look at what happened to the aluminum hull:

















Everywhere salt accumulated unseen, stayed wet and just ate up the hull!

Taking a look at the underside where hull sat on bunks:

No dissimilar metals here either... just wet salts... and straight line corrosion only where boat sat:



Salt is not actually doing the dissolving of aluminum. Salt is merely an accelerant according to how aluminum is created in the first place:

"The Hall–Héroult process is the major industrial process for smelting aluminium. It involves dissolving aluminium oxide (alumina) (obtained most often from bauxite, aluminium's chief ore, through the Bayer process) in molten cryolite, and electrolysing the molten salt bath, typically in a purpose-built cell. The Hall–Héroult process applied at industrial scale happens at 940–980°C and produces 99.5–99.8% pure aluminium."

A molten salt bath is used to make aluminum! And a salt bath is also what makes quick work of destroying an aluminum hull.

Another report says: "Although sodium ions carry the current through the bath, the cathode reaction extracts aluminum and leaves at the interface a melt that is richer in sodium fluoride..."

According to the science, the destruction of aluminum is greatly accelerated by the introduction of salts (that carry the electrolysis ions) to the hull surface puts the electrolysis process on steroids, and combined with Florida's heat speeds up the process even more!

Point is, yes aluminum can be used in saltwater, but its usable life is greatly diminished here in Florida.

This hull was unrepairable and unusable. I could not trust the hull in open water. I imagined the hull cracking and unzipping under my feet while out on the water. 100 pin holes and a swiss cheese hull caused me to just scrap this old boat.

[Capt. BassinLou]

The construction of today's aluminum boat is made completely different from yesterday's aluminum boat, especially when they are made for salt water use. Today's saltwater aluminum hulls do not have wood inside them and preventing electrolysis is key.  With proper maintenance and care, today's tin bay boats will last a long while.

[FloridaFishinFool]

Different construction can help but the aluminum used today is the same grade used in the past.

Regardless of boat construction, the aluminum in new boats will dissolve just the same as older boats.

There is no sure bet protection from saltwater damage.

[WTodd]

It's not the aluminum you have to worry about, it's all the hardware. IF the boat was made for freshwater, IMO it should stay in freshwater.  But if it's a bay boat or similar, go for it


Sent from my iPhone using Tapatalk

[Capt. BassinLou]

It's not the aluminum you have to worry about, it's all the hardware. IF the boat was made for freshwater, IMO it should stay in freshwater.  But if it's a bay boat or similar, go for it


Sent from my iPhone using Tapatalk

^^^ This ^^^

[FloridaFishinFool]

There is no questioning the fact that salt water destroys aluminum no matter what shape or size or construction configuration. Put aluminum in salt and it is downhill from there. No if's, and's or but's about it. But what may surprise some is what the experts say the best solution is, and it is NOT just maintenance- that can make it worse by forcing salts deeper into crevices. It is actually going through a scientific process of adding zinc anodes to the hull that will deteriorate instead of the aluminum hull because physics dictates the weakest metal will give way.

Presently that metal is the aluminum hull. Adding zinc anodes will slow the deterioration. Outboard motor companies do it.

I found a great article on this subject that covers what I said and what Lou and others mentioned about construction, but it is not a solution for this problem. Only trying to slow it down...

https://www.boatingmag.com/protecting-aluminum-boats-from-salt-water-corrosion

Protecting Aluminum Boats From Salt Water Corrosion
Aluminum boats require special care to prevent salt water corrosion.

By David Seidman  February 12, 2013


Boating Magazine

In 2012, boaters bought 77,150 aluminum boats. They're light, economical, nearly maintenance-free, easy to repair and almost impervious to damage. The Coast Guard and Navy prefer them for small craft, and many commercial boats are aluminum, as are many recreational craft. Their high strength-to-weight ratio means they can be built lighter and therefore can run faster for a given amount of power, and are easier to trailer. If you're looking for the ideal boatbuilding material, aluminum could be it. The only problem is that it's the wimp of the electrochemical schoolyard, being beaten up and corroded away by almost every other metal except for zinc and magnesium.

Want to be a saltwater metal head? Aluminum can seemingly dissolve away in salt water when in the presence of other metals. Builders do everything they can to prevent this, but once the boat is in your hands it's up to you to keep it alive. Here's how.

How It Happens
We're talking about galvanic corrosion. Back in science class you'd say that this is where one metal in an electrically conductive solution (such as salt water) gives up atoms when connected to a dissimilar metal in that same solution. Losing atoms means that the metal is falling apart, or corroding. In the slip aboard your aluminum boat, you'd say that this is where your hull becomes pitted because of a bronze through-hull on a neighboring boat.

The rate of corrosion of a metal on its own is determined by how chemically active it becomes when put in salt water. The more active, the more susceptible it is to corrosion. The less active, the more resistant it is to corrosion. When not in contact with anything else, most marine metals such as aluminum, bronze and stainless steel will corrode away at a reasonably slow rate. No danger there. But connect different metals, one active (aluminum) and the other a lot less active (i.e., a copper penny), in water and atoms will start to flow. And the aluminum will start to fall apart.

The Good News
When not in contact with other metals, aluminum can do quite well in both fresh and salt water, needing only ­bottom paint to prevent fouling. However, to play it safe, the American Boat and Yacht Council (ABYC) recommends that "aluminum vessels shall have a protective paint coating that provides a high [electrical] resistance barrier between the aluminum and the water."

Above the waterline aluminum does even better. When continuously exposed to oxygen, it develops a film of aluminum oxide so dense and well bonded to the metal that it prevents further corrosion. That's why many commercial and military craft leave aluminum bare from the waterline up: There's no need for protective paints, cosmetics aside. As you can see, building an aluminum boat for salt water takes thought. The right alloys must be used, welding must be done just right, and parts must be carefully assembled.

Fiesta, a Florida pontoon builder that bills its boats as "built for use in salt water," isolates hardware and stainless-steel bolts from the aluminum with nylon washers. Hull compartments have drains with silicone-sealed nylon plugs that can be opened to drain accumulated moisture. They also employ dedicated mounting brackets for sacrificial anodes, and their hulls and extrusions are made from thicker metal.

Better aluminum boat builders don't allow crevices or joints that collect water, and avoid upturned brackets and channels that trap water. Moisture, including condensation, must drain away, with no sealed or dead air spaces. An emphatic spokesman for Premier Pontoons said, "We are constantly doing pre-emptive detective work to stop corrosion before it starts."


Zinc or Swim
Engine manufacturers, as well as boatbuilders, attempt to save their aluminum products by attaching sacrificial anodes. As long as the anode is electrically connected to the part, either by direct contact or by wire, it stuffs the aluminum with excess electrons so it loses those rather than the aluminum giving up its own electrons. The zinc? It erodes — sacrificing itself for the benefit of the boat or motor.

Unfortunately, there is no formula to tell you how many anodes you will need and what size. In the beginning, it will be a matter of trial and error. A good place to start is the ABYC's procedure. Inspect the anodes every month. Go with many small ones rather than a few large ones. If you have the right amount, your "zincs" should be about halfway gone by the end of the season, and replaced each spring. If they are not wearing away, they are either too large (rare) or not making good contact with the aluminum (common). Well-made anodes should have cast-in plates and fasteners to maintain good electrical connection throughout their lives, and they should meet military spec Mil-A-18001J (or higher last letter).

Don't go nuts with zincs everywhere because aluminum won't tolerate being overprotected. In mild cases, the zinc develops a crust and stops working. But if things get too far out of balance, you can generate an alkaline solution that will start eating away at the aluminum. An early sign of this is the softening or blistering of the bottom paint.

How Much Zinc?
Use too few anodes, and the fittings are not protected. Use too many, and the anodes erode quickly and may blister paint. A multimeter and a reference electrode help to nail down the right amount.

1. Place a silver/silver chloride electrode in the water near the item that is to be protected.

2. Touch the positive probe to the fitting. Note the meter's reading in DC millivolts.

3. Connect a sacrificial zinc of the proposed size to the metal part to be protected. Put the zinc in the water and note the new meter reading.

4. Protection is adequate when the new voltage is 200 milli­volts (0.20 volts) more negative than the reading noted without the zinc.

[FloridaFishinFool]

Boating Magazine

The Trouble with Tanks
Even if you don't have an aluminum boat, you probably have aluminum fuel tanks. While these can be perfectly safe, the U.S. Coast Guard noticed a recurring problem with leaking tanks. So it asked Underwriters Laboratory to see why. Not surprisingly, UL found that corrosion caused 92 percent of the failures. Most of it was caused by how the tanks were installed.

In general, aluminum tanks should be left bare. Paint can help. But if it's not properly applied, it wears away, scratches or peels off, and moisture gets under the paint, concentrating and accelerating corrosion.

The most common fittings used in fuel systems are usually made from brass. Screw one of these directly into an aluminum tank and add some moisture, and you've got serious galvanic corrosion. Isolate these fittings from the tank by using 300-series stainless-steel washers or adapters.

The tank's supports must not be moisture-absorbent, such as carpeting is. Suitable materials are stiff neoprene, Teflon or any high-density plastic. Water should drain from all tank surfaces when the boat is at rest; the bottom of the tank must be at least a quarter-inch above the hull to let air circulate and above the level normally reached by bilge water. The European standard says "no less than 25 mm [1 inch] above the top of the bilge pump inlet or the bilge pump automatic float switch."

A fuel tank should be accessible for relatively easy inspection via a screwed-down, caulked hatch, but that is often not the case. Many builders install tanks so that a saw is needed for inspection or replacement. Too bad.

13 Ways to Prevent Galvanic Corrosion
1. Don't mix metals, or at least use metals as close to each other as possible in the galvanic series.

2. Bolts should be less active than fittings; they're small, so loss of metal is more serious.

3. Take all measures to electrically isolate fittings from each other, even on small craft.

4. Securely fasten anodes, and ensure there is firm contact with the metal to be protected.

5. Never paint an anode. Be sure the metal to which it is fastened is free of paint, scale and dirt.

6. Impressed current voltage should never exceed 1,300 millivolts when protecting aluminum.

7. Always repair paint chips and scratches that expose bare metal as soon as possible.

8. Avoid using any lubricant made with graphite aboard a boat made from aluminum.

9. Employ an isolation transformer whenever the boat's connected to AC shore power.

10. Don't use an automotive battery charger aboard a boat, especially an aluminum boat.

11. Paint only with primers and coatings specifically designed for aluminum.

12. Wash the aluminum boat down with fresh water after every use to remove built-up salts.

13. Keep hooks, sinkers, bottle caps and other metal debris out of the bilge lest they wreak havoc.

DIY the Right Way
Protecting your aluminum boat and equipment from the rigors of the marine environment.

Starbrite

Adding Hardware
Ideally, you'd use aluminum fittings and fasteners, minimizing the chance of galvanic corrosion, but these are hard to find. Instead use 300-series stainless steel. This works fine if you isolate the fitting with plastic washers or pads and keep the water out with a polysulfide or polyether bedding compound like Star brite polyether Boat Caulk (starbrite.com).

Interlux

Bottom Paint
Interlux and Pettit sell copper-free, aluminum-compatible paint systems backed by excellent application instructions and tech support. It takes lots of prep, plus attention to detail, to do this right. Visit yachtpaint.com (Interlux) or pettitpaint.com.

Load Rite

Ditch Your Carpet

To prevent hull pitting caused by trapped moisture, replace carpeted trailer bunks with plastic, such as these plastic bunk covers from Load Rite Trailers. Slippery plastic also makes launching easier.

[FloridaFishinFool]

Based on my own experiences with aluminum and salt which is an ongoing situation... my current boat has some minor salt damage, but it has been repaired and still usable.

Today I would not ever buy a like new or used aluminum boat or an outboard motor that has been used in salt water.

I stopped looking in Florida for these items. I now search out vintage aluminum boats in states that do not have salt water next to it. I have been burned now too many times to count by buying salty dogs.

Never again!

[FloridaFishinFool]

One issue that needs to be cleared up is that when someone puts an aluminum boat into salt water, there are actually at least 3 different types of corrosion that will occur depending on the boat and situation.

1)Electrolytic corrosion

2)Galvanic corrosion

3)Salt corrosion

Quite often these 3 are confused with each other, but they are not the same and the results on the aluminum boat hull and motors is also not the same. So let me post here brief definitions of all 3 for purposes of this thread- because what I am most interested in showing in this thread is #3 since it is by far the most important type of aluminum corrosion because it has NOTHING to do with dissimilar metals as is the case with electrolytic and galvanic corrosion- which salts actually accelerates the corrosion and with our summer heat is even further sped up to boat destruction as I have found out personally more than once.

The purpose of this thread is to simply share information to maybe prevent someone else from experiencing this same problem and save them the money and trouble, as well as to help anyone identify a potential problem with their own boat as I have gone through over the last 30 years or so of using aluminum boats here in Florida.

1)Electrolytic corrosion of aluminum:

Electrolytic corrosion is often confused with galvanic corrosion. While galvanic corrosion is driven by the difference in corrosion potential between two metals, the electrolytic corrosion is driven by the external sources of EMF. In the case of large motor bearings and generator bearings, induced EMF of the shaft results in current flow in the bearing, resulting in bearing corrosion in the shape of pinhole-type pits formed on the bearing surface.

Similarly, in the case of electrolytic corrosion of pipes, high-voltage direct current equipment and marine equipment, some external leakage current is always the driving force for the corrosion.

Prevention of this form of corrosion involves devices that break the continuity of the circuit or providing an alternate low-resistance path to connect the leakage current directly to the ground. For example, in the case of motor or generator bearings, a current collector mechanism with a brush holder and a brush makes contact with the rotating shaft, connecting the shaft to ground. Alternatively, the bearing pedestals may be insulated from ground to break the path of leakage current.

[FloridaFishinFool]

2) Galvanic corrosion

Galvanic corrosion (also called ' dissimilar metal corrosion' or wrongly 'electrolysis') refers to corrosion damage induced when two dissimilar materials are coupled in a corrosive electrolyte. It occurs when two (or more) dissimilar metals are brought into electrical contact under water. When a galvanic couple forms, one of the metals in the couple becomes the anode and corrodes faster than it would all by itself, while the other becomes the cathode and corrodes slower than it would alone.

The driving force for corrosion is a potential difference between the different materials. The bimetallic driving force was discovered in the late part of the eighteenth century by Luigi Galvani in a series of experiments with the exposed muscles and nerves of a frog that contracted when connected to a bimetallic conductor. The principle was later put into a practical application by Alessandro Volta who built, in 1800, the first electrical cell, or battery: a series of metal disks of two kinds, separated by cardboard disks soaked with acid or salt solutions. This is the basis of all modern wet-cell batteries, and it was a tremendously important scientific discovery, because it was the first method found for the generation of a sustained electrical current.

[FloridaFishinFool]

3)Salt corrosion of aluminum

Salt Damage on Aluminum

All metals will corrode in the presence of salts. Though aluminum does not exhibit rusting like steel does, it will develop a chalky film and pitting in the metal surface when exposed to salt for long periods. A neutral soap and water wash will help remove the oxidized film. If the oxidation has built up for a long time, a buffing wheel will help remove it from the aluminum surface. To stop the corrosive effects, however, you must apply a protective coating to the aluminum and keep the coating maintained over time.

[FloridaFishinFool]

Based on these 3 types of corrosion, as stated they are often confused because they overlap each other and actually work in combination with each to accelerate the rate of aluminum corrosion greatly.

For example, one rule every aluminum boat owner should follow if they care about protecting the hull from damage and corrosion is to never ever use the hull as part of the boat's electrical distribution.

In cars and trucks and vehicles we drive every day on the road, it is very common for the chasis, frame, and body of the vehicle to be used as a common ground for the entire electrical system in the vehicle.

But in an aluminum boat this is a huge no no because of electrolytic corrosion requires the flow of electrons through the aluminum for this type of corrosion to occur: "electrolytic corrosion is driven by the external sources of EMF".

So a good solid general rule in all aluminum boats is to never use the hull as part of the electrical distribution system because the flow of those electrons and protons causes aluminum deterioration.

All aluminum boats should use a floating ground. All of the boats electricity should stay separate from the hull.

But even this does not stop electrolytic corrosion because there are other sources of electrical energy present, however small, over time it does have a damaging effect.

[FloridaFishinFool]

With galvanic corrosion electricity does not have to be present for the corrosion to occur. It is caused by dissimilar metals coming into contact with each other:

"Galvanic corrosion (also called ' dissimilar metal corrosion' or wrongly 'electrolysis') refers to corrosion damage induced when two dissimilar materials are coupled in a corrosive electrolyte. It occurs when two (or more) dissimilar metals are brought into electrical contact under water. When a galvanic couple forms, one of the metals in the couple becomes the anode and corrodes faster than it would all by itself, while the other becomes the cathode and corrodes slower than it would alone.

The driving force for corrosion is a potential difference between the different materials."

The weaker metal ALWAYS gives! And in the case of aluminum boats, it is almost ALWAYS the hull. Who uses bolts and hardware that is softer than aluminum? Almost no one. So here in lies the problem.

Just putting two dissimilar metals together in water causes the corrosion. Add salt, it accelerates the corrosion. Add electricity and you know it, it even further accelerates the deterioration. Add heat, and it gets even faster.

On my 1973 AlumaCraft F7 boat that I still use to this day, when it was given to me I had to repair and overhaul it and I found some serious problems that had to be repaired.

One problem was not so bad... the previous owner had broken the oar lock mounts and used rusty old hardware to repair it. A nut and bolt and washer. All made of rustable steel. This is what I found when I removed the oar lock mount- galvanic corrosion caused by dissimilar metals and accelerated by salt and heat here in Florida:

The hull was completely eaten through. Just corroded away at this spot and it was not even in the water. Salt in the air, and moisture in the air along with dissimilar metals did the hull in


For my simple repair, I did some research on the precise aluminum grade used on my boat and then went and found the same grade of aluminum hardware. So I made my own aluminum washers from the hull of the other AlumaCraft boat I scrapped shown above in this thread. And I used an aluminum bolt and nut at this location so that all the metals would be the same and therefore no galvanic corrosion will continue at this location. I even coated the hull and hardware to prevent electrical contact between all 6 parts joined at this spot.

[FloridaFishinFool]

But the real kicker problem I found with my old 1973 aluminum boat was some serious salt damage beneath the transom knee where all the water in the boat collected and where all the salts were deposited and not able to rinse out, when in fact rinsing actually pushes the dissolved salts deeper and deeper into unprotected places no one can get it. So the salts just sit there and continue to destroy the aluminum and that is what I found in the boat above which was scrapped and the boat I use now.

This is what plain old salt and water does to aluminum. It is not galvanic corrosion because there are NO dissimilar metals present here. And it is not really electrolytic corrosion because electricity did not do this.

This is salt corrosion plain and simple.

I found the transom knee raised up. I knew there was a problem under it just because of how the corrosion had caused expansion between the knee and hull.












So you want to put your aluminum boat into saltwater and rinse it after every use in saltwater and call it proper maintenance? It won't help. Salt Away, a product that neutralizes salts might be a better option because rinsing with a pressure hose will indeed push salts deeper into places you won't want it to go just like this old boat:

[FloridaFishinFool]

Off topic comment deleted.

[FloridaFishinFool]

Off topic comment deleted

[D.W. Verts]

I sold boats for a long time. One rule in the boat business in MISSOURI is that you NEVER trade for a boat that came from saltwater. Period. Like it was stated above, it's the hardware that suffers as much as anything. I've seen stainless steel that was as rotted as a bad tooth. All the little snaps and buttons and trim pieces and radio doo dads just fall apart (or weld together).

And saltwater engines. No matter what the sticker says, they were pretty much throwaways.

The big issue was when a guy would get a "steal" on a boat from the coast. Like the dude what got a 26' Marathon Sportfisher one time. He figured that he STOLE it. Until we scrapped everything, and I mean EVERYTHING off the hull and chunked it. Including, eventually, the motor. And we had to CUT it off, then repair the transom afterwords.

Good care and maintenance helps. Flushing everything with fresh water is good. But you can't get it all, then there's the boat that sits in the marina on the water all of the time. Just butt ugly.

We had a guy from Delaware come in once lookin' to buy a new bass rig. His trade, a five-year-old boat, had NEVER been in salt water. But the guy live in sight of a salt water estuary, and that was enough. His boat was so bad, and the TRAILER was so bad, that I couldn't believe that he'd made it so far inland. In fact, that trailer didn't survive the week.

And these were GLASS boats. I've seen aluminum melt into the ground due to electrolysis. I've seen a one piece hull become a two-piece. I'd hate to see first hand the effects of salt on one. I'm sure a complete coating of paint/epoxy or whatever would help. But you still have your hardware/depthfinders/trolling motor etc. to think about.

[Deadeye]

Main point is Kent, you have a Train of Thought and No One is going to change it. You will dig through hours of Google searches until you find an article that supports what you say is the truth.

That boat you showed is an old style of boat that used wood as the transom support. Most of them back then did. Some used Treated Wood thinking it would be better, but were drastically wrong. The Treated Wood actually reacted with the Saltwater in accelerate the Corrosion Process.

The Wood absorbs and holds the Salt, just as your pictures shows.

As Lou pointed out in the very first reply to this thread, Today's Boats are a far cry from the Boats built even in the 1990's. Almost 100% use No Wood in the Transom, Over 90% use no wood at all.

The Aluminum Boats made for Saltwater use are painted with Corrosion Resistant Paint.

But take a new Aluminum Boat built today and use it in Salt and or Fresh water for 30-40 years and guess what? There will be issues. Things wear over time. Using an old boat as Proof that you can not us an Aluminum Boat in Saltwater is just, well not a good example.


As Dale and Others have pointed out Everything Used In or NEAR Saltwater wears out quicker than the Same Thing used Inland. Cars, Air Conditioners, and yes Boats.


But I doubt anything I posted will change your mind. After all you once had an old boat given to you that had corrosion on it, so all boats must be the same.

[FloridaFishinFool]

No, not all boats are the same. But all marine grade aluminum is the same. I've experienced it on 2 boats and 2 Yamaha outboards.

The point of this thread is what salt does to marine grade aluminum 5052 and 6061.

Boat shape and paint may prolong longevity, but mother nature always wins.

Even boat manufacturers do not cover any damages to boat hulls used in salt water:



take a look at exclusion (J)Galvanic, or stray current corrosion, or corrosion caused by salt water.




Same with Ranger boats:

13. Damage to trailers from use in salt or brackish water

15. Damage to aluminum hulls from use in salt or brackish water


RH Boats warranty says the same... no warranty for boats corroded in salt water period!

ITEMS NOT COVERED BY LIMITED WARRANTY:

A. Paint, peeling, scratches, chips, blistering, flaking, chalking or fading
B. Corrosion or damage caused by:
a. Fuel spills or over filling
b. Use of harmful cleaners or solvents
c. Electrolysis
d. Improper use of antifouling paint
e. Dissimilar metal
f. Salt water as a result of zinc anode absence, cathodic protection device and or
improper storage/moorage.

Kind of ironic aluminum boat manufacturers don't cover salt water damage...

[Deadeye]

As I said.

Thanks for proving me right.

[FloridaFishinFool]

Does proving you right include thread hijacking?

I started this thread to show what salt does to aluminum. It is not about trying to change my mind or persuade me to develop a belief that some how mankind has found better boat shapes that resist corrosion better.

So you are proved right in that your belief is not convincing enough to merit a change in thought in that direction.

The rate of dissolving 5052 and 6061 is the same for any boat of any shape.

So far all I have seen is a difference of opinion along with an unreasonable expectation that I begin to believe it too. And I don't. No reason to.

Rather than divert this thread into a combative personal hijacking why don't we stay on topic and show with science or facts or something with substance to it that proves today's aluminum boats are adequately constructed or built to withstand salt.

Prove to me why your opinion trumps the facts I have presented?

[FloridaFishinFool]

Aluminum and fiberglass boats have another critical metal that does not do well in salt and that is copper used in wiring and electronics circuit boards.

Just recently I saw under the deck of a boat made just a couple of years ago. The previous owner ran it in fresh water but the boat sales place ran it in brackish water.

The copper wiring was turning green from corrosion. The terminal blocks were corroding already.

The copper wiring was so oxidized solder would not adhere.

And this is on a 6 year old boat everyone swears was not used in salt but only brackish as if that makes it all better. It doesn't.

New or old salt will do damage. No doubt about it.

[SteveTX]

Does proving you right include thread hijacking?

I started this thread to show what salt does to aluminum. It is not about trying to change my mind or persuade me to develop a belief that some how mankind has found better boat shapes that resist corrosion better.

So you are proved right in that your belief is not convincing enough to merit a change in thought in that direction.

The rate of dissolving 5052 and 6061 is the same for any boat of any shape.

So far all I have seen is a difference of opinion along with an unreasonable expectation that I begin to believe it too. And I don't. No reason to.

Rather than divert this thread into a combative personal hijacking why don't we stay on topic and show with science or facts or something with substance to it that proves today's aluminum boats are adequately constructed or built to withstand salt.

Prove to me why your opinion trumps the facts I have presented?

This post is very odd/ironic/contradictory. On one hand you say,"It is not about trying to change my mind or persuade me" only to end it with,"Prove to me why your opinion trumps the facts I have presented?". You then go on to discuss thread hijacking and to stay why don't we stay on topic and your very next post goes on about another critical metal, copper. In your words,"I started this thread to show what salt does to aluminum."

And you don't want any other opinions unless in your eyes they are convincing enough to merit a change in your thought. And when presented with something differing from your belief, your response is to dismiss it as merely a difference of opinion along with an unreasonable expectation for you to consider/believe. 

15 posts to explain what salt does to aluminum.

Its your thread I just think it might have went a little better had you stated you had a old aluminum boat(s) that the salt got to really bad. Throw out some good marine aluminum info you learned dealing or researching with the boat(s).

Something like if your considering aluminum for a saltwater application here are some things that might help you not have a boat like mine. The industry standards are 5052-H32 and 6061-T6 for marine use. 5052-H32 is preferred over 6061-T6 in marine applications. 5052 is the most popular but is a little worse about stress cracks and corrosion of the two. 6061 welds better but needs to be heat treated after being welded. Which is why 5052 gets the nod a lot over it. And roll with some pics.   

I'm pretty sure a discussion would follow. In today's world I would be willing to bet some really cool alloys are out there that may be the next great boat material. There are so many things being developed beating a 50 yr old known issue over and over isn't changing much or learning a whole lot. And it wouldn't be about proving to you anything. Its a discussion you don't have to be the all knowing source in a discussion.

[FloridaFishinFool]

You are right. Fred is right.

I made a mistake. I contradict myself. Won't happen again.

We should be here to encourage discussion and apparently this is not the way.