Get another ultrasound?

[Captain Pegg]

Just now, MtB said:

 

 

I bet two adjacent ultrasound thickness readings on the baseplate from one of my boats would ALWAYS give different results...

 

 

 

 

 

 

Even on a new plate adjacent readings will vary. A 10mm plate can have up to 1.0mm variance in thickness overall.

[MtB]

1 minute ago, Captain Pegg said:

 

Even on a new plate adjacent readings will vary. A 10mm plate can have up to 1.0mm variance in thickness overall.

 

 

Yes I thought the thickness tolerance was massive on rolled steel earlier but wasn't that sure. 

 

I think it is quite possible for 10mm plate to look and measure like 3/8" imperial plate i.e. be 9.52mm thick. Although I can't remember why that was being discussed, or even if it was this thread!  

 

There must be a tendency to always try to roll at the thin end of the allowable tolerance in order to eke 5% more profit out of the product supplied. 

[Captain Pegg]

1 minute ago, MtB said:

 

 

Yes I thought the thickness tolerance was massive on rolled steel earlier but wasn't that sure. 

 

I think it is quite possible for 10mm plate to look and measure like 3/8" imperial plate i.e. be 9.52mm thick. Although I can't remember why that was being discussed, or even if it was this thread!  

 

There must be a tendency to always try to roll at the thin end of the allowable tolerance in order to eke 5% more profit out of the product supplied. 

 

Absolute thickness and variation in thickness tolerances are different things but a 10mm plate could in theory be as little as 9.15mm. It could also be a lot more than 10mm thick, but what it cannot do is have two places that vary by more than 1.0mm (for a 2000mm wide plate but potentially by more if a larger plate is cut down to size). 

 

 

[Sphinx123]

22 hours ago, Captain Pegg said:

So you have a 1989 boat - that appears to have been built with a 12mm baseplate - and has some localised loss of material that you are dealing with properly and it retains 10mm minimum baseplate and 5mm minimum side thickness. Even more importantly you have little to no pitting because that's what will get you rather than general hull loss.

 

I'd say that's pretty good, I've seen worse in the bottom of boats and I think many folk are oblivious to what is happening to the top surface of their baseplate.

 

   

Good to know about the pitting. And thanks for all your advice! I appreciate your balanced viewpoint and common sense approach.