Permissible level of pitting during boat survey

[colinnorth]

I have just had a boat survey done and have found 1.2mm pitting in 6mm steel. Is this a worry?

If one was purchasing such a boat, at what point would you decline the purchase of said boat? (in 6mm steel - 1.2mm? 1.4mm?)

[mrsmelly]

That would depend greatly on the age of the boat. If its 30 plus years I would say its fine. If its 3 years old I wouldnt touch it. Is the pitting around the waterline?

[Alan de Enfield]

17 minutes ago, colinnorth said:

I have just had a boat survey done and have found 1.2mm pitting in 6mm steel. Is this a worry?

If one was purchasing such a boat, at what point would you decline the purchase of said boat? (in 6mm steel - 1.2mm? 1.4mm?)

 

You will struggle to get fully comp insurance if you 'thinnest' reading is 4mm or less.

Whilst it may have originally been 6mm what is the thinnest reading the surveyor has found ?

Edited January 2, 2022 by Alan de Enfield

[colinnorth]

The boat is built 2005, fitted out 2006, registered with CRT 2006.

The thinnest reading is 4.8 and is below the waterline,

There is a galvanic isolator fitted and the boat is permanently connected to the shoreside mains. (At least for the last 4 years that I know of)

Last blacked in 2018.

Rust layer showing all along the waterline.

[MtB]

1 hour ago, colinnorth said:

I have just had a boat survey done and have found 1.2mm pitting in 6mm steel. Is this a worry?

 

I'd only be worried if the pitting was 6mm or more. 

 

But then I'm a bit gung-ho about such things. It's not like a house survey. 

[Mike Tee]

Any old surveys available? (worth asking the current owner - if he wants to sell he'd probably make them available). If there was no change in the pitting over, say, the last 5 years, I wouldn't worry. If all the pitting had occurred over the past two years, I'd be concerned.

[Alan de Enfield]

 Is the 6mm the base plate or the 'sides' ?

I'd be surprised if any builders were still using 6mm base plate in 2005.

 

Also of concern (you could say my 'hobby-horse') - does it have the necessary RCD documentation and certificates of compliance ?

[Bee]

A few pits here and there are one thing, a forest of pits all over the place are another. In my experience epoxy paint stops pits progressing - thing is that corrosion is so full of variables that  in any group of boats they can all be different. Personally I would not be too alarmed at pits slightly over 1mm deep but I would be keen on getting a good modern coating on the boat and then maintaining that coating with regular dockings - actually that goes for any boat of any age.

[LadyG]

1 hour ago, Bee said:

A few pits here and there are one thing, a forest of pits all over the place are another. In my experience epoxy paint stops pits progressing - thing is that corrosion is so full of variables that  in any group of boats they can all be different. Personally I would not be too alarmed at pits slightly over 1mm deep but I would be keen on getting a good modern coating on the boat and then maintaining that coating with regular dockings - actually that goes for any boat of any age.

My boat, 20 years old was epoxied when new, and as far as I can ascertain not touched all that time, no GI, probably on shore power most of the time, metal piles too 😭

I hauled it out, washed it and there was one tiny orange spot the size of a new penny, absolutely no pitting anywhere 

I wire brushed it, well the yard staff did that, no sign of rust. 

Three coats of Jotamastic 90 from SML (no connection, but good advice and price). Job done. 

Based on that one sample, I would only look at boats that had been epoxied from new. But having had a hull survey, I would ask the surveyor for his opinion, if positive, I'd probably buy it and arrange a week off in summer to prep and paint the hull. 

PS you could ask for a discount of course, but not every owner will find that acceptable. 😊

Edited January 2, 2022 by LadyG

[dmr]

2 hours ago, MtB said:

 

I'd only be worried if the pitting was 6mm or more. 

 

But then I'm a bit gung-ho about such things. It's not like a house survey. 

 

So what would happen if the pitting got to 6mm?  Do you know about these things? Have you got any real first hand experience?

 

 

(😀)

[MtB]

1 minute ago, dmr said:

 

So what would happen if the pitting got to 6mm?  Do you know about these things? Have you got any real first hand experience?

 

 

(😀)

 

I have.

 

Barry comes along with his crane and lifts you out, an Simon puts a new boat on the underside...