[Silt rotting hull base plate]

Thank you everyone for your thoughts... 

My boat has had to have a full 8mm overplate on the base plate and the stern had to be completely rebuilt! Nothing to do with the silt it seems, just crap steel initially, and then many years of neglect before my time.

I now have a non-sinking, happy boat!! And a happy boater too!

Thanks again ?

[Silt rotting hull base plate]

Just now, Murflynn said:

you make it sound as if the whole of the base plate has lost 2.5mm. .................  very very unlikely.   if that really is the case it suggests that the meter being used needs re-calibrating.

 

the whole of the baseplate cannot be checked - only a number of points.

did your welder notice some corrosion and just measure at those points?

was the corrosion present at the same locations last time, and did he check the same locations?

 

as others have said, any meaningful survey procedure should be done in a very controlled and well documented manner.    my guess is that a welder doing thickness checks would not follow such procedures.

No, just the centre line. 

When she was out last year he checked along the centre as there were signs of pitting then... I blacked her myself after treating with vactan, so Im pretty sure I did a good job.

2 minutes ago, Alan de Enfield said:

 

As I noted above, someone else on the forum had a very similar experience and was fully fitted out with GI and anodes - If I remember correctly it was traced to a neighbouring boat leaking 'electrical worms'.

 

Hope fully whoever it was will see the thread and comment.

Ok thanks for that... fingers crossed as I'm getting a bit stressed at the moment :o/

[Silt rotting hull base plate]

22 minutes ago, Matt&Jo said:

That's a lot to eat through in such a short time...galvanic isolater fitted/working? Are you hooked up to marina electrics?

All working, but yes have been in the Marina since Feb last year

 

40 minutes ago, mrsmelly said:

What makes you think 2.5 mm has disappeared in such a short time? Did someone measure the exact parts of the base plate or is this two different people and their findings? Sounds like a big mistake somewhere to me?

 

4 minutes ago, Tam & Di said:

You'd have to be in a fairly strong acid to lose that much steel in just 12 months, and I can't believe it would be anything to do with the mud - even galvanic corrosion would not work that actively.

 

To look at it in practical terms, the Dutch say 4mm is acceptable plate thickness for a pleasure barge, but a hull that thick would have complete disappeared in under 2 years at the rate you mention. What does the surveyor who took the measurements say about it?

 

Tam

Thanks guys... it's been "pinged" with an electronic doofer (sorry, technical term evades me). My engineer said he thought it was due to the silt, but like you say, I was stunned at how much she has lost! I daren't go back to my old mooring now because at that rate I'm going to wake up one morning with no boat round me.

The main loss is down the centre if that helps?

4 minutes ago, Tam & Di said:

Another point is you mention the guy doing the welding as being the person who did the sonic survey. Is he actually an accredited surveyor? It is quite easy to get false readings unless you are really experienced, and even then most surveyors would back them up with a hammer test.

 

Tam

Yes Tam... he does welding, engineering and surveys. I do trust him as he has an excellent reputation in Cheshire

[Silt rotting hull base plate]

I had her out last year for blacking and she was checked over then. 

She's out again now for another weld by the same person, so it is accurate

6 minutes ago, Matt&Jo said:

That's a lot to eat through in such a short time...galvanic isolater fitted/working? Are you hooked up to marina electrics?

All working, but yes have been in the Marina since Feb last year

[Silt rotting hull base plate]

I have just found that my base plate has deteriorated by 2.5mm over 12 months. I have the right number of anodes, but the Marina where I'm based is stilted up to the max. Does anyone know if silt would help erode the base plate please, and can I do anything about it legally?