Getting the bottom done

[MtB]

For metal to start coroding it needs oxygen. There is not much of that 2ft under the water.

 

How do the fish down there survive then if there's no oxygen?

 

Enough oxygen for fish means enough to support corrosion. And baseplates corrode.

 

 

MtB

[Bloomsberry]

Maybe that's why baseplates don't corrode much, all the fish have gobbled up all the oxygen down there

Seriously, I think it's common knowledge that more corrosion occurs at the waterline of the hull than down below. Maybe water only contains a minimal amount of oxygen so the amount of corrosion to the hull is also minimal ?

I've read that the right hand front edge of the baseplate tends to wear a lot due to it being in contact with the canal bottom when passing other boats etc. Obviously blacking the bottom won't prevent wear such as this.

Edited August 15, 2014 by Bloomsberry

[sbillis]

I picked up the boat from Debdale wharf last weekend. I had the sides and bottom grit blasted and epoxy resin coated. They also put on new anodes, painted the tunnel bands, blasted and epoxy coated the weed hatch, plated over the old redundant gas fridge outlet and welded in a few minor pits. After they had finished they clened the boat.

 

I have to say they did a superb job in a thouroughly professional way. Nothing was too much trouble and I would recommend them to anybody.

 

Simon

nb Bulrush

[Sabcat]

I'll be interested to see what the base plate looks like on this boat when it comes out. The original base plate(s) were from 1982 and 1986 (it was stretched in '86) and had mostly lost less than 0.5mm except in trenches 1/2" wide and in some places 4.5mm deep and 4 - 15 ft long in star shapes. The cause of these trenches is unknown, they might be something to do with a bad electrical earth, they might have been something else (perhaps something to do with the boat being on fire in 1985). The boat was stretched again while it was out and the old bottom over plated with 6mm. The hull sides were grit blasted and blacked with 2 pack epoxy and 3 anodes fitted each side. The base plate wasn't. The anodes in the middle are visible and haven't lost much at all in 7 years and the hull side coating is still pretty much perfect, no waterline rust or any other rust is visible.

 

It's coming out again in April for another couple of coats of epoxy on the hull and a look at the base plate.

[Richard Batten]

The yard my boat is in won't allow grit blasting so I'm stripping back to bare metal using abrasive discs with a grinder and painting with 2 pack epoxy primer. I'm preparing and repainting the base plate which isn't a nice job and am painting all sides of cabin and hull both externally and internally. It's a couple of weeks work and I wouldn't be doing it if it won't be worth it in the end to have the boat painted in the more advanced coating. It's the same paint used on ocean going tankers so is really much tougher than it needs to be for use on the canal.

Edited October 2, 2014 by Richard Batten