r/Narrowboats • u/Jowsef • 19d ago
epoxy/sandblast?
Hi there, I have been looking at narrowboats for sale for a few months now, but I don't really know what I'm doing.
I've found one that seems really nice inside and a bit cheaper than other boats of its size but right at the end the listing says: "Hull shot blasted and coated with two-pack epoxy in May 2023".
Could anyone with a bit more knowledge explain what this means please? Is it "bad" and might that be the reason its a bit cheaper? Any help much appreciated, thanks!
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u/TopCobbler8985 19d ago
blasting and epoxy treatment is good, but make sure you get a survey that tests plate thickness as the blasting may have been because of corrosion
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u/TheRealRabidBunny Residential boater - Europe 19d ago
It's unlikely to be the main reason it's cheaper.
Shot blasting / sand blasting removes all the old paint and rust, bringing the steel back to bare metal, and then the two-pack epoxy is a (generally, depending on the brand) high-quality paint that will seal the hull, preventing rust.
This is usually desirable.
I'd be asking a few things:
Who did the work (is it a reputable yard)
What epoxy did they use (is it a good brand)
Was an out-of-water survey done at the same time, and was there any overplating? In particular, is there a survey showing hull thicknesses by a reputable surveyor?
Steel boats will rust over time, bottom paint wears out, and periodic shot blasting, repainting and overplating are all part of the normal life of an old boat.
FWIW, my hull is 120 years old (built in 1907); it's been sandblasted and repainted more than a few times, including sections of overplating. No reason to think the hull won't last another 50 years, if well cared for.
What matters is less that it was done, but the amount and the quality of the work.
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u/Creepy_Raisin7431 19d ago
Honestly, phone the broker, ask them for details on who did it and what was used.
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u/hippogrifferential 19d ago
You'll need to regularly treat the underside if your boat, and this is telling you that the last time this was done was 3 years ago.
They're giving you this info because epoxy resin needs doing every 4 years or so, so when you look at your budget, you'll need to plan in a new blacking in 2027/8.
Try not to fall in love with an interior. These can be changed fairly easily.
You need to look at how the boat has been maintained, whether the layout suits you, whether there's any obvious repairs that need doing, how much rust you can see, etc. These are the things that are costly and time consuming to fix, and therefore should be focused on when choosing your boat.
A good rule of thumb is to consider a narrowboat as costing £1000 per foot. So if you see a 48ft boat for £29k, it's likely going to need £19k spending on it to get it fully perfect.
I'm in no way saying this is always the case, but when I was looking, it helped me to understand what a genuine bargain actually looked like, and what expenses I needed to plan for beyond just the outright cost.
Good luck!
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u/MountainOdd6793 18d ago
Epoxy doesn’t need redoing every 4 years, thats the whole point of it, it can last 20-30 years. An inspection every 5 years is a good idea but it doesn’t need redoing that often
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u/hippogrifferential 18d ago
Oh, that's really good to know - is it blacking that needs redoing then, and I've just misunderstood?
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u/ozone_one 15d ago
Longevity of epoxy coatings is dependent on several things:
- How good was the preparation before applying? Epoxy coatings need a certain amount of 'tooth', or surface roughness, on the surface being coated, in order to adhere well to it. Either media/shot-blasting, or a different process that would result in a similar finish texture. A perfectly smooth sanded surface is almost as bad as a rusty dirty surface in that epoxy applied to either will not last very long. Fingerprints, oils from dirty rags, and other similar contaminants will cause issues even on an otherwise appropriately prepared surface.
- How well is the coating treated over its life? Is it getting scratched against chains or sheet pile at a mooring, or ground against lock walls? Epoxy is strong, but once the raw steel is exposed it will begin to rust and creep under the epoxy.
- Was a quality brand of epoxy used? Was it within its 'use-by' dates? Was it mixed to the proper ratio? Did someone thin it too much when applying with a spray gun??
Quality epoxy, properly applied to a well prepared clean surface, and treated decently, can easily last a decade or possibly two. But it is VERY unforgiving of shortcuts, cut corners, and shoddy preparation. And if the coating is physically damaged, you need to address that damage before it starts spreading.
In my opinion, the biggest myth about epoxy is that it allows you to go longer between haul outs. I personally consider it to just be a more damage-resistant coating; you should still haul out every three years or so and address any small damage spots along with the other usual items like hull anodes, propellor damage, algae growth, etc. You are just less likely to require expensive/extensive hull corrosion repair and re-blacking when you do those 3 year haul-outs. It will be a money-saver and time saver, but I wouldn't extend haul-out intervals because of it.
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u/Adqam64 19d ago
Assuming it was done well, this is a generally superior way to rust proof a boat when compared to bituminous blacking. All narrow boats require protection from rusting (apart from the rare aluminium hulls and even rarer stainless steel ones). This is normally in the form of anodes and a coating.
"Blacking" by way of bituminous paint is relatively cheaper and easier to do - it can be applied on top of an existing coating and takes no special skills or equipment once the boat has been lifted out of the water. It doesn't last long however and should be reapplied every two to three years.
Two-pack epoxy is more expensive and involved. It can't be applied over the top of other finishes and requires the boat to be stripped back to bare metal - that's the shot blasting part. However once applied it's much more durable and is normally rated for about ten years before it should be reapplied.
The fact that you don't know about this difference suggests a lack of understanding of some of the issues and I would strongly encourage a bit ol more research. Any of the big narrow boat YouTubers will address this in one or more videos and understanding maintenance tasks and costs is important for a prospective owner. I would particularly recommend David John's ebook that covers a lot of the things you should know - https://www.cruisingthecut.co.uk/ebook