steel boats

[scoty]

Anyone experience with steel motorboats, for example I guess inside on the metal condensation must/could be a problem,

Where does it go, logic says into the bilges, but thats eventually so how would I solve
any problem.
Or am I missing some thing,,,,ie insulation between inside metal surface and the wood finish.

I·m thinking about buying a metal motor cruiser and this question came up.

 

[MapisM]

Well, there's insulation of course, particularly on pleasure boats, but I've also seen commercial steel fishing vessels with decades of full time service ad I can assure you that you wouldn't loose your sleep due to condensation.

Otoh, there's plenty of more important pros and cons with steel boats, and your question makes me wonder if you already evaluated them. Because if not, probably you should go through the first 30 or so chapters of the book, before worrying about this one...!

 

[PCUK]

If it is a modern steel boat, say 30 years or younger then it should have been epoxy-coated inside and out which means very little corrosion. Insulation stops any condensation. My 25 year old steel boat always smells fresh inside even when left closed up for several months. Unlike a lot of GRP boats which smell as if they are rotting from the inside out!

 

[lenseman]

Anyone experience with steel motorboats, for example I guess inside on the metal condensation must/could be a problem, . . . . . . .

I would suspect this type of question is a daily event on any one of a number of Narrowboat or Inland Waterways forums?

You could try joining a NB forum and asking about the various differences between anchors?

 

[panthablue]

I have a steel boat. It's a 30 feet sailing boat. I bought the bare hull in 1980 and fitted her out myself. After advice from local boat builders I had the inside of the hull sprayed with polyurethane foam, about an inch thick. It covers everything from the waterline upwards.

the thing about polyurethane foam, (unlike polystyrene), is that it is totally waterproof. The boat hull on the inside is stall as good as new.

Polyurethane foam is also a good insulator, so it keeps the temperature inside the boat more stable, than if it were bare steel. Because of this, we don't suffer any more condensation than a fibreglass boat, probably less in fact.

the other feature is that it is good for soundproofing, so we don't get the tinny clangs you might expect from a steel boat.

It has been very successful

I hope this helps

 

[Assassin]

You have to be careful with polyurethane foams as they come in closed cell and open cell types, only the closed cell foam is waterproof. Many make this basic mistake and assume all PU foams are waterproof and install open cell foam and the hull sits quitely rotting away under the open cell foam.

 

[panthablue]

Absulutely

 

[Sandyman]

If you read threads on some of the sailing forums the doom & gloom merchants will tell you they wouldn't touch a steel boat with a barge pole, because they rust. They often spout out untrue statements as fact when anyone with real knowledge can see that what they are saying they have read in a book / magazine.

Best solution to condensation, where possible, is to stop it happening in the first place.

Also think it odd that your first question is about condensation !!
Has one of the doom & gloom merchants brought this to your attention ?

 

[panthablue]

When I told the owner of a boatyard that I was buying a steel boat, he warned me "be careful of dust in the bilges". I asked what he meant. "Well they're just so very dry" he answered.

He was pretty well right. Currently we have a small leak in one of the windows,, but normally she's a very dry boat.

Yes we do get rust, but I think that is more to do with the lack of paint we put on when we built her. We put on undercoat and top coat - all epoxy, over the primer that the boat came with.

What we should have done was put on several layers more. I heard of a steel boat owner who did this, and didn't have to do any more painting for 15 years.

We have to patch up every winter. It's the biggest downside to owning a steel boat.

the up side is that, (according to other boat owners) she looks in far better condition than a fibreglass boat of the same age. We launched in 1986.

 

[PCUK]

My 26 year old boat has the original two-pack over epoxy on the topsides still shining and rust free!
As you say, if painted correctly from new then no problems.

 

[panthablue]

I'm very jealous. Mine has been patched and patched over the years. Mind you, she still looks pretty good

 

[Sneds]

I can vouch for PCUK's boat, a real stunner

 

[Assassin]

When you have 8mm of steel plate it takes a lot of rusting through, but its very easy to epoxy coat the hull with modern steel epoxy paints and many will last for decades.

 

[Gavi]

We've got a 30ft steel motorboat, built in 1999. She is very dry inside - the spiders love her almost as much as we do!

 

[Capt Cautious]

Sprayed PU foam is a good bet. The following to be aware of

1. Closed Cell, otherwise you've bought a sponge.
2. You may need to spray a fire retardent coating onto it. The surface spread of flame characteristics may not please some insurance companies. Best to check. A phenolic foam has far better flame retardent characteristics.
3. When burning PU gives off a cyanide gas.
4. Make sure cabling is well clear to avoid molecular migration and deplasticization with subsequent embrittlement of cables.
5. A vapour barrier on top is not a bad idea either, this stops interstitial condensation as the foam is not a vapour barrier. The vapour drive is from inside to out, and at some point within the foam the vapour will reach iits dew point. This can actually create a worse problem than not having any insulation at all. Good ventilation must always go hand in hand with good insulation.
CC