Anyone considering a "project" boat.....

ahicks

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Just a heads up, in stripping down my newest project boat ('93 19' Grumman alum. deck boat) getting it ready for all new plywood, I've discovered ALL of the foam (sprayed and block) in contact with the bottom of the boat is nearly completely saturated with water. It will ALL have to be removed. Not a huge deal if you already have the floor off, but something else to consider when looking at something like this....
 

jbcurt00

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Yep, same revelation on nearly every Starcraft or any other tin boat posted here....

Oh and wet foam against a tin boats hull creates a toxic corrosive reaction that chews holes in the hull.... 1 reason some (most? Many?) strip all the paint off a tin boat down to bare tin.
 

bchaney

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Heard of the waterlogged foam issue but never knew about any chemical reaction between polystyrene and aluminum. Not sure I understand how that works but lesson learned - don't leave your beer in a Styrofoam cooler too long!
 

ahicks

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Where the foam I'm pulling contacts the alum. is below the floor line. On this boat anyway, that means no paint. I haven't seen any corrosion to speak of anywhere. Caution regarding painted ares noted though!
 

jbcurt00

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Heard of the waterlogged foam issue but never knew about any chemical reaction between polystyrene and aluminum. Not sure I understand how that works but lesson learned - don't leave your beer in a Styrofoam cooler too long!

No, in a boat, waterlogged foam traps water against the tin hull. W out fresh oxygen the water causes (creates) a galvonic response w the tin and becomes corrosive. Its the water thats the problem, not the foam. The foam is merely what traps the water against the hull...

Same is true for transom plywood holding water against the tin transom.

In some cases it also seems trapped water flows into nooks and crannies below decks, riveted seams, around ribs and chines, under fuel tanks, etc, and once there also eventually starts to chew on the hull..... Perhaps it was already corrosive before it flowed into those secondary areas, maybe it is simply enough water, sitting in them long enough to create a toxic environment.....
 

GA_Boater

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First beer cans are not bare AL.

And second if you leave beer in a cooler, any cooler, long enough to observe this phenomena, you better look at the drink by dates. Said brew is not for for human consumption. :smile:


Wet foam, wet wood, wet anything in constant contact with bare aluminum can cause corrosion. Look at all the holey AL fuel tanks and eaten transoms threads. Usually one thing in common - AL in contact with wet material. The aluminum can't form it's self-protective oxidization.
 

Texasmark

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Funny. I just bought a 2002 Crestline 1750 Fish Hawk I think is the name of it, aluminum boat and it has what i heard was poured in foam....lumpy looking stuff on the top just like something somebody would pour in and it would setup just about af fast as you poured it in. Pretty resistant to thumb pressure but you could get it to deflect somewhat and the surface was smooth. The foam looked really horrible as there was some obvious water damage to the 7 ply marine plywood deck.

After removing the affected plywood I was worried about soaked foam. So I cut off a chunk of it. It wasn't like the white coffee cup styrofoam sheets that were in my '65 Starcraft Hokiday I/O, but it was tan and the bubbles were tiny. I took the sample over to the sink and tested it.....floated like a leaf blowing across the lagoon. Not only that, I couldn't get the foam to dislodge from the hull.

So I blew it off, fixed the soft wood spots and finished her up today.
 

ahicks

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You got lucky! Betting that boat was carefully covered and/or garaged.I bought this boat pretty reasonably, knowing it had been ignored/uncovered for years. I was after the bones really, knowing full well it was going to be a serious project. I just wasn't expecting to have to go through this foam deal. I had heard about the possibility, just didn't occur to me that I might have to deal with one. I've had several other alum. boats (16-22') and had not run into this before.

This is the poured in stuff as well, and THOROUGHLY saturated. Probably 30% or better. The fact it was poured is likely part of the issue. The way it's done I don't see how in the world the builders thought this boat might drain properly/dry out if it got wet. Oh well, not the end of the world. Will be a nice boat I won't likely have to mess with much for a while when done.

Just wanted to get this potential out in front of somebody thinking about taking on a project!
 

jbcurt00

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You know that tin is a totally different element than aluminum right?
Yes, yes I do

Well versed in tinny boat construction, esp the vintage ones

You wont mind if we refer to boat decks as boat floors instead of soles, will you? I mind, a great deal actually, but thats how some describe them....

Tinnys are what many boaters refer to aluminum boats as, esp the older, vintage ones. This boating forum, 2 others I belong to, 1 of which is 100% vintage aluminum boats, and the half a dozen or so FB groups I belong to do as well.

Back to your topic achicks...... sorry for the side track...
 

ahicks

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A brief side track often serves to inform and keep things interesting. I don't mind them a bit. Just as likely to be guilty as anyone else. -Al
 

5150abf

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I thought all boats were project boats!

Had mine for 20 years and could buy a really nice dinner if I had a dollar for everytime I told the wife "this is the last thing I am doing to the boat....."
 
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