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Hull thickness?

We used to live on old (1976) narrowboat and we want to come back to old times. We have found a boat from 1997 built by BJ Welding (we believe it is small company because there is not too much of them on internet) and we think about buying it.
Our old boat was specified as 6/5/4 (when new) and after 30 years (the survey) it had still 5 mm of solid bottom and almost same thickness of the rest.
New boat was built as 10/6/3 but after just 6 years in 2002 survey the thickness was 8.2/5.1/3 and there was an information that the bottom was not painted. The seller says he took her out every 2 years and painted her and he seems to be trustworthy but...
I've read on internet that sometimes newer boats have the steel of very poor quality comparing to old ones and I want to avoid the disappointment.
I know the simplest thing would be to take her out and measure the thickness but we have very tight budget.
The second thing is the engine - BMC 1500, older then the boat (it is not said how old) but in good condition (the owner is the mechanic) with more then 3000h on the clock. I wonder if it is good engine comparing to others?
Well, I thank you in advance for any help and advice.
Kind Regards

Asked by: Joanna and Jarek   | 3.16pm, Tuesday 21 December

WW says:

The easy answer first- the BL1.5 engine is quite a reliable engine, and the parts are very easy to get hold of- Calcutt Boats are a good source of advice, and spares. You can download, free, the handbook and workshop manual from their website. There are many BL engines running from the 1970's in hire boats, having done much more than 3000 hours, so don't worry about that. They can be a bit smokey (and burn more oil than newer engines) and common faults include oil leakage from the rocker box, worn piston rings (but fairly easy to replace) and sometimes a habit of breaking forward legs. oil pressure should be about 15 lb/in2 at tickover on a hot engine, rising to 30 under load, cruising. Just check for easy starting from cold (no more than 20s heaterplugs, followed by less than 10s cranking is good).
The hull thickness is another matter! though there is some evidence that steel quality has changed, it probably hasn't that much. I must admit, I have never heard of the shell builder that you are looking at, however, as long as you like the lines, and the price is right, I wou;dn't be too worried about that.
There is an assumption that the original builder actually was using 10mm plate for instance (unless you have an original survey, this is very hard to prove!)- though the amount of wear shown isn't unusual. Also, where the plate thickness is measured can influence the readings (for instance, it is likely to be much thinner on the rubbing edge of the base plate, than in the centre of the base). Round waterline corrosion is likely to be more of a concern.
As for painting, alas, many owners do not paint the baseplate, assuming that a) it won't corrode and b) the paint will wear off. Neither are good excuses, and I fear that it is often used as a way to get out the difficult job of painting under the baseplate, especially as many drydocks down't allow good access under!.
So, your seller might have painted the boats hull every two years, just not the baseplate!
Good anodes, proper painting, and repairing any damage (such as scrathces) is probably the best route, but as you still have a thick hull, then I wouldn't be worried!
Hope that helps- any clarification, please let me know!

Mark Langley  | 5.00PM, Tuesday 21 December

Readers say:

Thank you very much for so professional and full answer. We think we will make an offer if everything would go right.
We wish you a Merry Christmas and Happy New Year.
Joanna and Jarek

Joanna and Jarek   | 10.14PM, Tuesday 21 December

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