Steel Boats and Welding

[haidan]

Originally Posted by Matt sachs

I talked with ( I think his name is Adam) at West system epoxy. He reccomended when working with old steel, to apply the epoxy with a brush, then go over it with a hand held wire brush and work it in really well. Then, go over it with another coat using just a paint brush. Has anybody done this? how did you like the results?

In my experience with coal tar epoxy it's best to apply subsequent coats before the under coat has had a chance to fully kick (the next morning), that was with new steel but if you're going to put paint on new steel it's always a good idea to bring it down to shiny metal anyway so I would treat it any different. I think the west system guy was just making the point that paint sticks best to a rough surface, thus the brush. Kinda depends how thick it goes on, I imagine lots of epoxies cure with a nice smooth finish, coal tar not so much.

[Yachts66]

Some time back I posted some comments on integral tanks that several here took exception to. In that post I said the information came from a well known designer or words to that effect. I did not feel comfortable quoting him directly because I hadn't received his permission to do so and our email exchange was private in my view. Anyway, Bruce Roberts has kindly allowed me to quote him and here is exactly what he's said on the subject:

Regards the integral tanks ... German Lloyds, Lloyds, Europe wide EU marine rules ... ALL forbid integral tanks ... as there are fewer rules in the US the brokers etc may not be aware of the rest of the world !!!

Now you know. My boat has them, and I see problems with non-integral tanks on small boats, but apparently others don't agree with me. I know from experience getting behind fuel tanks to maintain the steel under and behind them can be a near impossible task, which is why I continue to prefer integral tanks regardless of what Lloyd's or the EU says.

Regards,

Thomas

[barnakiel]

Integral tanks - illegal - because of environmental concerns - not because of design safety issues.

b.

[Yachts66]

Doesn't make them a better idea on small boats though!

Thomas

[Brent Swain]

The rule makers don't give a rat's ass what maintenance headaches they give you, or if your boat rusts out prematurely. That's your problem, not theirs. They won't pay your costs of following their rules.
In Canada, any govt guys need a search warrant to even come aboard. Don't allow them aboard. No problem, unless you want to give yourself one, by inviting any govt rep aboard.

[SaltyMonkey]

Interesting....

[Yachts66]

When you clear customs they come aboard, and I don't think you can stop them if you want your boat admitted into the country.

Thomas

[osirissail]

Originally Posted by barnakiel

Integral tanks - illegal - because of environmental concerns - not because of design safety issues.
b.

I would agree that it is a environmental rule versus safety or structural. Of course Lloyds is not a rule maker but the EU Marine rules probably are a legality issue for boats manufactured in the EU. I suspect it is the new "double hull" requirement for any fuel carrying component of a vessel. In the USA the fuel tanks are supposed to be static pressure tested after manufacture to detect any leaks. That would be rather difficult to do with an integral tank.

[haidan]

Originally Posted by osirissail

I would agree that it is a environmental rule versus safety or structural. Of course Lloyds is not a rule maker but the EU Marine rules probably are a legality issue for boats manufactured in the EU. I suspect it is the new "double hull" requirement for any fuel carrying component of a vessel. In the USA the fuel tanks are supposed to be static pressure tested after manufacture to detect any leaks. That would be rather difficult to do with an integral tank.

I pressure tested my integral tank, wasn't hard just screwed pipe caps to the vents and put a few pounds of air pressure in and sprayed soapy water around all the joints, just have to be out of the water to do it.

[GordMay]

Kasten has a good overview on integral tanks:
Integral Tanks for Boats

[GordMay]

Originally Posted by haidan

I pressure tested my integral tank, wasn't hard just screwed pipe caps to the vents and put a few pounds of air pressure in and sprayed soapy water around all the joints, just have to be out of the water to do it.

Integral tanks must pass a 5 psig pressure test, provided by being filled and having a stand pipe of 11.5 feet (3.5 meters). If the head pressure will be greater in service, the stand pipe used for testing must be to the greater of the two.

[Stillraining]

Originally Posted by haidan

I pressure tested my integral tank, wasn't hard just screwed pipe caps to the vents and put a few pounds of air pressure in and sprayed soapy water around all the joints, just have to be out of the water to do it.

Originally Posted by GordMay

Integral tanks must pass a 5 psig pressure test, provided by being filled and having a stand pipe of 11.5 feet (3.5 meters). If the head pressure will be greater in service, the stand pipe used for testing must be to the greater of the two.

We are required to test sewer mains to 3.5 to 4.5 PSI depending on municipality....I would agree that air testing is faster, more convenient and potentially less messy....However a 80 to 120 gal tank with dimensions of say 5' x 8" x 18" potentially is a small bomb at those pressures.

I have blown 6" sewer pipe caps 10' in the air at 4.5 psi as its about 280 pounds of pressure on a 6" cap...IIRC

So be mindful of that...I did use air to test my Ski boats fuel tank but it wasnt integral to the boat and I removed it from the boat to do it as well.

[Brent Swain]

Originally Posted by Yachts66

When you clear customs they come aboard, and I don't think you can stop them if you want your boat admitted into the country.

Thomas

Neither Canada nor third world countries have any such rules for yachts. The rest are easy to avoid.
As Long as I am in Canada I don't allow govt people aboard.

[Matt sachs]

I did it. It took a month (it seemed like it anyway) in the tennessee summer sun, but I scaled and primed the inside of that big boat. No hull plates had to be replaced. but one internal support had to be cut out and replaced.
Everything below the waterline (inside the boat)was coated with west system epoxy, and above the water line was primed after being treated with Phosphoric acid.

I have a boat load of new questions. pun intended. :-)

The keel is divided with a water proof bulkhead. the forward keel is full of ballast with the exception of the area for the bilge pump.
The aft keel is empty, with a water tight hatch on top. So, being the curious type that I am, I cut a big hole in it to see whats in there. Nothing. It looks like it would hold about 200 gallons. I want to scale and clean this chamber and use it as a keel cooler for the engine. Is this a crazy idea?

[Yachts66]

Not all at. There are many advantages to keel cooling, just don't use water and keep in mind that unless you are going to go with a loud and hot dry exhaust system you'll still need to pump salt water into your wet exhaust system to keep it quiet and cool. 50/50 solution of antifreeze is what most use in the keel cooler. If you're headed south be mindful that all that hot water inside your boat will be a heat source you may not want. Be sure to give a few coats of epoxy paint to the interior and bilge as well.

Regards,

Thomas