Metal Floors

[Adam C]

I am replacing nine floor timbers this haul out. Instead of using lumber, I want to use metal ones to open up the bilge, have shorter bolts, etc.

I have two options - one is to make them out of stainless and use bronze bolts to attach to frames and keel - What do you guys think? Real heavy stainless (316 - 1/2" thick) shouldn't corrode that quick

OR

Mild steel floors, hot dip galvanized and then use Galvanized bolts.

I'm not even going to consider cast bronze due to the expense, foundry hassles, etc.

Opinions?

[imported_Conrad]

I've always thought this would be a great way to go, especially for a repair job- simple but extremely strong floors, fabbed up out of bar stock. A sawzall, hydraulic pipe bender (modified), and a mig welder, and away you go!

My preference would be the galvanized, primarily because what you see happening to the exposed surfaces is what's happening to the backside. With stainless, the hidden surfaces may be experiencing crevice corrosion while the outside looks great. Plus, I like the idea of the compatability between the floor material and the bolts, and their minimal effect on other fastenings in the hull. With the money you save, one can make them even thicker to help them last even longer. I'd galvanize, then bed in tar, and forget them for years.

[raycon]

Curious, What are the cross section dimensions of the timbers you are replacing versus the SS?

[Andrew Craig-Bennett]

Galvanised mild steel. My boat's lasted 66 years with them; cannot be too bad!

Mind you, I thing that forged strap floors are probably better than angled plate ones. Need a good blacksmith (and if you find one, you can get them made in wrought iron!)

Having said that, I have two friends who have replaced the steel floors in their boats with bronze, so perhaps it cannot be very difficult.

[Adam C]

Raycon,

I am replacing a floor that is around 12" tall and about 2 1/2" thick.

1/2" or 5/8" steel will be way stronger and lower profile.

Andrew, I had thought as much - thanks for the answers.

[pwilling]

Bronze replacement floors -- what do you do, get somebody to cast them?

[Ed Harrow]

Bronze can be fabricated, ie welded/brazed. I spoke with the god of welding about doing it. He said, "No sweat, hot knife through butter." Now, as for forming the arms to the frames, well that may well be a bit of a project, but I can't imagine it being worse then ss.

[mic]

In Larry Pardey's book CLASSIC BOAT CONSTRUCTION THE HULL, he made plywood patterns for his bronze floors then took them to the foundry to be cast. It didn't look that difficult, it would be interesting to know what the difference in price realy is between 316 stainless and Manganese bronze. ;)

[cbob]

Adam, It sounds like you may be considering replacing 12 inch by 2 1/2 inch vertical web wood floors with metal strap floors to lower the profile? You may be able to duplicate the stress distrubtion with lower profile fabricated or cast metal web floors, but how much lower would require a little engineering, if these floors are in way of the ballast keel, ballast keel bolting. Luck finding a solution, cbob

[JFH]

My question is, how are you removing the metal floors that you have now? Are they bolted together or welded?

The reason I ask is because I am considering a replacement of my 45 year old galvinized frames.

Jim