Base plate repairs

[Technical Tony]

Hi,

We had the survey done today on our potential purchase, and there seems to be an issue with the baseplate.

The surveyor advises that most of the baseplate is in good order with around 9mm of thickness, but there are two areas near the stern where it seems the baseplate has worn to around 7mm in places due to scuffing the bottom of canals with some 1 to 1.5mm localized pitting near the chines. He has advised that "shoeplates" be fitted near the edge and go back under the baseplate for a distance of 10 inches, and each plate be around 4 foot in length. He says that wear in these areas is common on both hire boats and private syndicate boats due to their excess use compared to privately owned craft.

Having followed as many threads on this forum as I can find about buying (or not) any boat that has been over-plated, should I get my deposit returned, walk away and keep looking, or, as he advises, get the repairs done professionally. I would keep the survey as a record for any future buyers to see why the plating was deemed necessary.

I don't want to be left with a boat that we cannot sell in the future because someone like me, won't buy or consider any hull repair fearing it's a bodge job.

Has anyone experienced this type of baseplate wear. The boat is 20 years old

[MrsM]

Don't know what price range your boat is. As someone in-between boats I would find an over-plated boat a bit concerning. However, in your case there seems to be a good reason. What is the boat's draft? Ours was only 2ft and there was no wear on the base-plate. If your prospective boat is deeper drafted, and the repairs are checked and signed off by a surveyor, I would see it as a pale pink - as opposed to red - flag. If the boat ticks your boxes and the cost of repairs is factored in I wouldn't see it as a game-changer.

Edited December 16, 2025 by MrsM

[mrsmelly]

It will scare some buyers off but some will not give 2 hoots, what price is the boat. Assuming 10mm at start of life then its going to sink in about 45 years time if the rate of wear remains the same, its quite a lot of wear for a boat of that age but some boats also at that age are near on scrap. How long is a piece of string? 

Edited December 16, 2025 by mrsmelly

[blackrose]

Remaining baseplate thickness in those areas is 7mm to the bottom of the pits? If that is the case then I disagree with MrsM as I can't see any good reason to overplate. 7mm is loads. If you're concerned about the pitting just get the pits welded or just blast and epoxy that area with a few good coats of Jotamastic 90. Job done.

Edited December 16, 2025 by blackrose

[Technical Tony]

4 minutes ago, MrsM said:

Don't know what price range your boat is. As someone in-between boats I would find an over-plated boat a bit concerning. However, in your case there seems to be a good reason. What is the boat's draft. Ours was only 2ft and there was no wear on the base-plate. If your prospective boat is deeper drafted, and the repairs are checked and signed off by a surveyor, I would see it as a pale pink - as opposed to red - flag. If the boat ticks your boxes and the cost of repairs is factored in I wouldn't see it as a game-changer.

On the certificate of conformity it's shown as 26 inches. The surveyor didn't think the boat overpriced, if the repairs are completed. Yes, I would want the repairs signed off before returning to the water.

[Alan de Enfield]

1 minute ago, Technical Tony said:

On the certificate of conformity

 

What is this certificate of conformity ?

 

Is this the RCD certificate ?

[Technical Tony]

24 minutes ago, blackrose said:

Remaining baseplate thickness in those areas is 7mm to the bottom of the pits? If that is the case then I disagree with MrsM as I can't see any good reason to overplate. 7mm is loads. If you're concerned about the pitting just get the pits welded or just blast and epoxy that area with a few good coats of Jotamastic 90. Job done.

This would be our first boat, so we don't want to get it too wrong, especially if we decide after a season that its not for us and want to sell. He wasn't clear whether the pitting was in the 7mm thickness, I assume so, as 1-1.5mm pitting on 9-10mm shouldn't be an issue should it?

The base plate doesn't seem to have ever been treated.

Edited December 16, 2025 by Technical Tony
correct spelling

[MrsM]

8 minutes ago, blackrose said:

Remaining baseplate thickness in those areas is 7mm to the bottom of the pits? If that is the case then I disagree with MrsM as I can't see any good reason to overplate. 7mm is loads. If you're concerned about the pitting just get the pits welded or just blast and epoxy that area with a few good coats of Jotamastic 90. Job done.

Agree with you in theory; however, if a surveyor has said that work needs doing and I had sight of the survey - which the OP says will be the case - then I would expect the work to be completed and signed off. I would not want to buy a boat that had not had recommended work completed without a substantial reduction in price. That said, I would be happy with pit-welding that is assessed & signed off by the surveyor. The OP is keen to avoid taking too big a financial hit on the boat if he needs to sell on again quickly.

Edited December 16, 2025 by MrsM

[Technical Tony]

Just now, Alan de Enfield said:

 

What is this certificate of conformity ?

 

Is this the RCD certificate ?

It was a build specification sheet we found in the boat files.

[MrsM]

What year was the boat built? This is potentially important.

[blackrose]

12 minutes ago, MrsM said:

Agree with you in theory; however, if a surveyor has said that work needs doing and I had sight of the survey - which the OP says will be the case - then I would expect the work to be done and signed off. I would not want to buy a boat that had not had recommended work completed without a substantial reduction in price. 

 

Perhaps I've misunderstood. If we're talking about the OP's survey they are under no obligation to show it to anyone when they come to sell the boat. And assuming several years have gone by when they sell the boat then that survey would be largely irrelevant to any prospective purchaser anyway. 

 

If the pits have been welded and ground flush then they might not even be noticed by the next surveyor. I know that some people don't like to grind pit welds flush but in either case it's proper repair if done well and doesn't carry the same sort of stigma amongst boaters as overplating. I realise overplating can be done well too, but it stands out like a sore thumb 👍🏻 and might put some people off. 

Edited December 16, 2025 by blackrose

[Technical Tony]

10 minutes ago, MrsM said:

Agree with you in theory; however, if a surveyor has said that work needs doing and I had sight of the survey - which the OP says will be the case - then I would expect the work to be done and signed off. I would not want to buy a boat that had not had recommended work completed without a substantial reduction in price. 

Are you referring to our possible purchase, or future potential buyers when/if we sell? please clarify.

5 minutes ago, MrsM said:

What year was the boat built? This is potentially important.

2005

1 minute ago, blackrose said:

 

Perhaps I've misunderstood. If we're talking about the OP's survey they are under no obligation to show it to anyone when they come to sell the boat. And assuming several years have gone by when they sell the boat then that survey would be largely irrelevant to any prospective purchaser anyway. 

 

It's not the pits as much as the wear. I appreciate the survey would be useless down the years, but I thought it might explain better why the repair was necessary, rather than any buyer thinking the section had rotted out.🤔

[MrsM]

1 hour ago, Technical Tony said:

Are you referring to our possible purchase, or future potential buyers when/if we sell? please clarify.

2005

It's not the pits as much as the wear. I appreciate the survey would be useless down the years, but I thought it might explain better why the repair was necessary, rather than any buyer thinking the section had rotted out.🤔

I'm referring to future potential buyers when/if you sell. For transparency, we bought our first narrowboat just as COVID struck. My o'half has over 30 years' experience as a submarine designer - and knows a great deal about how and why boats float or sink - and yet it was totally down to me to choose our boat. I am quite risk-adverse unlike hubby. We bought our boat privately after the sad death of its previous owner less than 18 months after purchase. We had full access to the previous buyer's survey and unrestricted access to the boat - including 10 hours cruising to and from the lift-out yard where we had it surveyed. I paid close attention to the issues highlighted in the most recent survey and commissioned our surveyor to check that these points had all been addressed. Had they not been I would have expected this to have been reflected in the price we offered. We had to very reluctantly sell our boat after 4 happy seasons' cruising due to lack of time. When we advertised it we shared our survey and the previous one. We sold the boat very quickly. Unlike many of the bods on this forum I have NO deep knowledge or experience of boat technicalities. This may be the case with any future buyers you come across. I simply want to caution against ignoring surveyors' advice as it may bite you in the bum. You are under no obligation to share your survey findings, but I believe doing so worked in our favour. If you love the boat and the price is right then go for it, but don't bank on future buyers sharing your optimism. As the boat was built in 2005 it should have a certificate of RCD/R (I never remember which is which) compliance. Some buyers won't care, but some will. I wish you much happiness on the cut.

Edited December 16, 2025 by MrsM

[Technical Tony]

4 minutes ago, MrsM said:

As the boat was built in 2005 it should have a certificate of RCD/R (I never remember which is which) compliance. Some buyers won't care, but some will. I wish you much happiness on the cut.

It has a certificate of conformity, the build specification, a Hull identification number and a plate with some build details fixed to the cabin. I'm told that means it had/has an RCD/R

[MrsM]

8 minutes ago, Technical Tony said:

It has a certificate of conformity, the build specification, a Hull identification number and a plate with some build details fixed to the cabin. I'm told that means it had/has an RCD/R

This should be referenced on the certificate - have you had sight of it? The HIN will tell you builder and build-date. The boat should also have a builder's manual for the structure, equipment and services. Many boats don't and sell without an issue. None of this is important to many experienced or ignorant buyers, although some brokers are becoming increasingly aware of the issue. Are you buying privately or through a broker? Don't be afraid of sharing information here - members have a wealth of experience and will offer wise counsel. 

Edited December 16, 2025 by MrsM

[Technical Tony]

3 minutes ago, MrsM said:

This should be referenced on the certificate - have you had sight of it? The HIN will tell you builder and build-date. The boat should also have a builder's manual for the structure, equipment and services. Many boats don't and sell without an issue. None of this is important to many experienced or ignorant buyers, although some brokers are becoming increasingly aware of the issue. Are you buying privately or through a broker? Don't be afraid of sharing information here - members have a wealth of experience and will offer wise counsel. 

Yes, the boat manual with the certificate is in it and I,ve seen it. The manual has a lot of data, wiring diagrams, build detail, fit out detail with model/serial numbers of appliances, appliance manuals etc. 

We are buying from a brokerage. My thoughts are that if we don't buy it, unless someone decides to buy without a survey, any surveyor will find the same issues and it will still need rectifying. If we can get the vendors to either have the repairs done, or negotiate a sufficient reduction in the price to cover the repairs, an otherwise nice boat that ticks so many boxes slips away and we go through the whole process again (and again?)

I am getting a couple of quotes for the repairs ready for when we have the written survey, thinking that at least if we get the repairs done, we can control the repair quality by a follow up survey by someone we trust.

[MtB]

2 hours ago, Technical Tony said:

The surveyor advises that most of the baseplate is in good order with around 9mm of thickness, but there are two areas near the stern where it seems the baseplate has worn to around 7mm in places due to scuffing the bottom of canals with some 1 to 1.5mm localized pitting near the chines.

 

 

If you want a perfect boat buy a new one. 

 

Given this boat has taken 20 years to lose 1.5mm-2mm of metal in the highest wearing areas, this boat is all set to sink in just another 90 years or so. 

 

Or put another way I'd buy it in a heartbeat, and never worry about it until 50 years after I'm dead. 

 

 

Edited December 16, 2025 by MtB
Add a bit.

[MrsM]

1 minute ago, MtB said:

 

 

If you want a perfect boat buy a new one. 

 

Given this boat has taken 20 years to lose 1.5mm-2mm of metal in the highest wearing areas, this boat is all set to sink in just another 90 years or so. 

 

Do you get my point? 

The voice of reason, knowledge and experience. Not all prospective buyers are so blessed. I certainly wasn't, and I've no doubt I will be just as cautious with our next boat. 

[Technical Tony]

Nicely put into prospective! New would be nice, but that's just a little out of our pocket depth😂😂

PS, what's a greenie?

[MrsM]

5 minutes ago, Technical Tony said:

Nicely put into prospective! New would be nice, but that's just a little out of our pocket depth😂😂

PS, what's a greenie?

There's an arrow in the bottom right corner of message boxes - you can use this to give feedback (positive, negative, indifferent etc) to posts.

[MtB]

7 minutes ago, Technical Tony said:

Nicely put into prospective! New would be nice, but that's just a little out of our pocket depth😂😂

PS, what's a greenie?

 

You know what happens when you sneeze....? 

 

OR

 

Press the little "UP" arrow button and it turns green! 

 

 

10 minutes ago, MrsM said:

The voice of reason, knowledge and experience.

 

Lol I have you fooled then!! 🤣🤣🤣

[Technical Tony]

1 minute ago, MtB said:

 

You know what happens when you sneeze....? 

 

OR

 

Press the little "UP" arrow button and it turns green! 

 

 

And there was me thinking someone knows I'm green (about narrowboats anyway)😄

[MtB]

14 minutes ago, Technical Tony said:

And there was me thinking someone knows I'm green (about narrowboats anyway)😄

 

 

Oh now don't start that. Narrowboats are anything but green.

 

If yoy want to be green, get a new(ish) house. Or even better, one like MrsM built. 

 

 

[David Mack]

3 hours ago, Technical Tony said:

The surveyor advises that most of the baseplate is in good order with around 9mm of thickness, but there are two areas near the stern where it seems the baseplate has worn to around 7mm in places due to scuffing the bottom of canals with some 1 to 1.5mm localized pitting near the chines. He has advised that "shoeplates" be fitted near the edge and go back under the baseplate for a distance of 10 inches, and each plate be around 4 foot in length. He says that wear in these areas is common on both hire boats and private syndicate boats due to their excess use compared to privately owned craft.

Narrow boats used to be built with 6mm (or 1/4") baseplates. The industry moved to 8mm then 10mm and sometimes thicker, mostly to give extra reserve against wear and corrosion, since baseplates are rarely painted. Insurers generally want a minimum of 4mm for comprehensive cover.

On that basis I don't see any need for shoeplates now, although it may be prudent to get the pits welded up. Just keep an eye on it when you have the boat out of the water for blacking (every 3 years or so). You can always add shoeplates later if the need arises, but if this is to be a single owner/family boat, that is likely to be decades away.

[Peanut]

I have construction drawings for a narrow boat, dated 2003, showing the base plate as "6mm, may be 8mm."

Thicker steel gives a reserve against corrosion, the extra weight just reducing the amount of internal balast needed.

The surveyers report highlights an area of wear that needs watching, and may give the opportunity to negotiate a reduction in price to offset his fee.

Pit welding if needed, would be sensible.