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Will my boat need replating

Hi I have a 1980s harbrough marine narrow boat the survey report reading said bottom plate5.5 to 6.1 counter base 5.5 to 6.1. I'm worried that it will need replating. If so how long would it be before I have to have it done??? Or how long before she sinks !!!!! Thank you

Asked by: jane  | 12.05am, Wednesday 25 July


WW says:

Many boats were built with 6mm (or even 3, 4 or 5mm) base plates- and are still afloat!
You don't mention what was the original (quoted) thickness of the boat- but I suspect that it was 8mm baseplate- and so, with regular painting and good anode maintenance, it might well be another 10-15 years before you need to consider replating.
However, if you had a survey, if there was any structural weakness, or need for replating, then the surveyor would (should) have reported this to you.
Don't worry- if your surveyor was happy, then the boat will be fine. It is worth considering though, repainting the baseplate, rather than leaving it unpainted as many boatowners do. Although paint may scrape off, and you need to ensure the boat is docked slightly differently (in a different position) every time you repaint (to ensure you get coverage of the bits it was sitting on last time in the dock), it is worth doing!
Also, if you have to go back to bare steel at any point, consider using one of the two-pack epoxy paints, as these give excellent protection to the metal below. However, any good film of paint will help reduce corrosion- as weill keeping the bilges dry internally (espcially the cabin bilge). Good ventilation here will help. Many boats collect condensation in the cabin bilge- if not sorted out, can rust the boat from the inside out!
If you want more information, just ask- but, don't panic!

Mark Langley  | 2.05AM, Wednesday 25 July

Galvanic isolators won't harm- but isolation transformers are better. Galvanic isolators mit work, though the evidence isn't that great. Isolation transformers are more expensive but work by giving full separation of the shore and boat side of the mains electric circuits. If you moor in a marina, then having one may be very useful, but if an isolated mooring then probably not really needed.
Blacking is best done as required- if you cruise lots, then every two years, if not cruising That often, then maybe four years plus. It also depends on the paint quality- epoxy based paints last many years longer than the cheapest bitument.
Painting the base plate will help- though convincing some boatyards that it needs doing can be problematic- not the nicest of jobs!

Mark Langley  | 6.37PM, Sunday 29 July


Readers say:

Would she benefit having a galvanic isolator,and how often would you recommend having her blacked every 2 years or 3? P.s the baseplate was originally 6mm thick.thanks for your advice.

jane  | 10.16PM, Friday 27 July

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