Steel Hull Construction

[steelboat]

valiente: maybe stainless bolts, with nylon washers, along with the gasket?
For gaskets I've used 1/16" nylon, and I know a rigger who uses cut up milk cartons when he's putting stainless on aluminum masts... works well for small stuff. Best, Bob www.sv-restless.com

[sailingdog]

Valiente—

Might be worth talking to a local plastics company and seeing if you can get some HDPE sheet in a long roll.

[Valiente]

Originally Posted by steelboat

valiente: maybe stainless bolts, with nylon washers, along with the gasket?
For gaskets I've used 1/16" nylon, and I know a rigger who uses cut up milk cartons when he's putting stainless on aluminum masts... works well for small stuff. Best, Bob www.sv-restless.com

Thanks for the suggestion. I have been thinking along the same lines as the crucial bit isn't strength, but physical separation. And SD, I have been considering HDPE as well, because it's easily drilled, but ridiculously tenacious, to judge by my chef's knives slamming into my HDPE cutting board, which I coarse sand once a year to get the stains out...

Funnily, I've contracted a chandler to make me some HDPE water tanks, so maybe I can get some Krazy Karpet thicknesses from him....

[sailaway21]

Nylon washers are used often on ships with aluminum ladders attached to steel decks and padeyes. It's worth mentioning that the resultant aluminum is not grounded to the rest of the boat/ship. Probably not an issue on the boat.

I'm reaching back here but, if memory serves me right, monel might be the most corrosion resistant bolts you could use. Not necessarily the strongest but, I believe, they'd be the most corrosion and least transmissive bolts you could use. Of course they're pricey. (g)

I'm also thinking that nylon might be a better isolator than the hdpe given it's ability to stretch and therefore expand and contract. I'm really not sure though.

[artbyjody]

Do a a search on I think Daschell - the pioneers in aluminum boats for the masses... their website has great resource on what to do and consider...I'd provide the links but it'd be better you find it ... [slurp]...ya get it...

[Valiente]

I'm not convinced the Dashews have a lot to say here, as they have ALL aluminum boats, and my issue is rebolting an aluminum roof onto a steel pilothouse, a roof that has plenty of wires running inside it with the potential for electrical mayhem.

I will research further. A fresh application of 5200 ISN'T going to be on the short list.

[popeyewanab]

Just wanted to say thanks for taking the time (especially Jeff's) to post on the subject. I'm looking for a used boat and found a 1987 steel 40' and believed steel would last a lifetime. The boat lies in a fairly remote area and I have contacted a local surveyor there, and while he can look for corrosion, I wonder if he can ascertain the current thickness of the hull to help determine what has been rusted away over the last 19 years.

[sailingdog]

How do the nylon washers prevent the ladders from being grounded if they're still bolted to the steel portions of the boat. Wouldn't the fasteners ground them???

Originally Posted by sailaway21

Nylon washers are used often on ships with aluminum ladders attached to steel decks and padeyes. It's worth mentioning that the resultant aluminum is not grounded to the rest of the boat/ship. Probably not an issue on the boat.

Yes, monel are more corrosion resistant than SS, but they're also far more likely to cause galvanic corrosion issues with both the aluminum and the steel.

I'm reaching back here but, if memory serves me right, monel might be the most corrosion resistant bolts you could use. Not necessarily the strongest but, I believe, they'd be the most corrosion and least transmissive bolts you could use. Of course they're pricey. (g)

Nylon expands and contracts as well. Nylon probably also absorbs water better than does HDPE. I'd think that HDPE is better for that reason along.

I'm also thinking that nylon might be a better isolator than the hdpe given it's ability to stretch and therefore expand and contract. I'm really not sure though.

[popeyewanab]

Hi all,

I am considering buying a 40' cutter steel boat and I'm looking for input on the builder and the original specs that follow. I have yet to get a survey and that will be critical. I plan on sailing the boat around the world as I liveaboard over the next 5-10 years. Details;

"Orca" Van der Stadt design. Built by Forges de Paimpon in France (Britany) and launched in 1987. The original thickness of the keel was 10mm, hull below the waterline 5mm, above waterline to the deck 4mm, and 3mm roof. The finished boat given zinc bath inside and out and then a coating of epoxy tar primer, 2 marin epoxy coats and 2 antifouling coats under the water line. I am told by the seller that the hull is in excellent condition, but after reading about steel corrosion I am very apprehensive about buying one that is now 20years old. Was this the best protection offered back in 1987, and what type of maintenance shouldhave been performed to maintain the integrity of the original protective coatings? Any input is appreciated.

[Plumper]

Originally Posted by popeyewanab

Just wanted to say thanks for taking the time (especially Jeff's) to post on the subject. I'm looking for a used boat and found a 1987 steel 40' and believed steel would last a lifetime. The boat lies in a fairly remote area and I have contacted a local surveyor there, and while he can look for corrosion, I wonder if he can ascertain the current thickness of the hull to help determine what has been rusted away over the last 19 years.

From 2002 - 2006 I was Captain of a riveted steel yacht built in 1921. Same construction technique as the Titanic. Although it had been through a few refits it was very shipshape. They tested the hull thickness using ultrasound and found a few thin spots and welded in doubler plates.

I would have a steel boat of my own if I could afford to keep a big boat. Probably a Waterline: Designers and builder's of fine metal boats >> Waterline Yachts