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Blacking A Narrow Boat – What’s All That About?

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Tue Jan 7, 2014 at 1:38pm

Why Do We Black The Hull?

The Basics – The hull is blacked to protect the bottom section of the boat, so specifically the area of the boat that is in the water and just above the water line. The “blacking” process protects the hull from rust, pitting, rubbing (through locks, other boats, banks etc) and generally extends the life of the hull.

Part and parcel of owning a narrow boat means that you need to carry out certain maintenance jobs and blacking is among one of those jobs.  Some maintenance work you will be able to do yourself, however blacking your narrow boat can be quite time consuming and something that you may not want to do yourself after reading this blog.

The boat will need to be out of the water for the blacking process to take place and there are three different ways that are actually used to get the boat out of the water. 

  • Dry dock, where the boat is floated into a chamber and then the water is removed.
  • Craning the boat out but this can be expensive. 
  • Slipway trailer, which is where the boat is put onto a trailer and a tractor pulls the boat out the water. This is the most cost effective and popular choice.

Types Of Coatings

There are two types of coatings that can be used to black the hull, Bituminous and Two Pack Epoxy. Epoxy paint is more expensive but it will last 5 – 6 years once applied and a Bitumen finished coating will last around 2 – 3 years.

If your boat is already coated with Bitumen you are unable to put Two Pack Epoxy over the top, you will need to get the hull “shot blasted” which means stripping everything back to the bare steel. This is a very expensive process and needs to be carried out by a specialised company.

A quick and easy way to check which coating is on the hull is to soak a cloth in white spirit and rub the paint, if the residue is transferred to the cloth it is more than likely to be Bitumen. Whoever undertakes the blacking process will check this for you before they quote and start the process.

The blacking process needs to be carried out on a dry day as the paint will not dry if applied in the wet and also will not stick if the temperature is too cold. Other than that the job can be done at any time.

Three Day Process Explained

Day One;
The Boat is pulled out of the water and pressure washed to remove the old blacking and debris like weeds, mud, and rust. This prepares the hull for the new application. You can also ask for a “scrubbler service” which is a machine used to pay extra attention to the water line area of the hull. Most companies will charge extra for this, so if required be prepared to pay the additional cost.

The boat is taken out of the water and the hull is pressure washed

Day Two
; The hull is now ready for painting and this has to be done manually with a small roller, the reason behind this slow manual process is the paint goes hard very quickly so it has to be applied in small sections.
The hull is ready for blacking

Day Three
; Repeat day two! The second coat gets applied and if required you can ask for an additional coat around the waterline (this may incur an additional cost). The boat is then left for 48 hours to dry before it is returned to the water.

The blacking is applied

Watch our You Tube videos for more information:

I think after you have watched the videos you will agree that blacking a narrow boat is not a DIY job.



John Forbes | Sat May 3, 2014 at 6:28pm
I am not sure many people would agree with you that two-pack epoxy can be applied over blacking. It should always be applied over bare steel, and if done that way, should last a lot longer than 6 years.
Whilton Sales Team | Tue May 6, 2014 at 3:07pm
Thanks for spotting that one! It's a mistake on the blog and we will amend that now. Woops, proves we are human!
megan | Thu Jul 3, 2014 at 4:07pm
Will any standard hardware store bitumen paint do...sika or the likes... or is it a special type we need to look out for?
Whilton Marina | Wed Jul 9, 2014 at 3:59pm
Make sure that the bitumen is suitable for blacking a narrowboat hull, Whilton Marina Chandlery sell it. see their website
Andrew Porteous | Wed Jul 16, 2014 at 5:37pm
Thank you Really enjoyed it.
Camille | Tue Oct 6, 2015 at 2:10am
Does the base of the boat need to be blacked?
Whilton Marina | Mon Oct 26, 2015 at 1:06pm
Yes the base & sides of the boat hull need blacking to protect the hull from corrosion.
Juliet Markland | Thu Nov 26, 2015 at 12:48pm
Could you send me a list of prices for undertaking blacking a 54 foot narrow boat Regards, Juliet Markland
Steven Austin-Vautier | Sat Nov 28, 2015 at 9:43pm
A useful article. We are considering 2-pack but cannot find a boat year that does it owing to the health and safety requirements. Any advice would be appreciated.
John Langford | Thu Dec 10, 2015 at 9:13pm
Never owned a boat but seriously thinking about it. Just one question at the moment- exactly how thick is the hull of a narrowboat? and does it depend on when it was built?
Whilton Marina | Mon Dec 14, 2015 at 4:44pm
Hello John - the thickness of a modern narrowboat is usually 10mm, however some older boats such as Springer narrowboats were built with thinner hulls.
Whilton Marina | Tue Dec 15, 2015 at 3:34pm
In response to Steven Austin-Vautier's question above regarding health & safety in relation to Two Pack Epoxy narrowboat blacking above. We contacted Steven who clarified that "It was the issue of fumes and having to wear special gear which many boat yards can't be doing with because of a Health and Safety issue" We understand that there are H&S procedures to follow when applying 2 Pack Epoxy hull coatings which may sometimes be difficult for a boat yard to undertake especially if working indoors.
Whilton Marina | Tue Dec 15, 2015 at 3:42pm
Hello Julie Unfortunately we don’t have the capacity to undertake any narrowboat hull blackings unless you are a moorer with us. But for a guide - our price for blacking a 50ft narrowboat would be £720 and a 60ft boat £864 inc VAT.
Richard Weston | Fri Aug 5, 2016 at 3:47pm
Very helpful information exchanges thanks. My question is in two parts. How much more expensive is 2 Pack Epoxy coating. What is the lifespan of anodes?
Whilton Marina | Tue Aug 9, 2016 at 2:06pm
Hello Richard, Two pack Epoxy is twice the cost of bitumen, but lasts two to three times as long as bitumen coating.The life of annodes depends on usage, and depending on how much crusing the boat does. Anodes are used to help protect the hull in the case of galvanic corrosion caused by electrical current flowing between connections and between dissimilar metals. The theory is that by attaching a piece of metal to the hull that is more reactive than the hull itself then this piece of metal will corrode first.
Paul Roberts | Sat Jan 28, 2017 at 1:56am
I have often wondered if adding a fibre-glass or even kevlar mat to the two pack epoxy would be a way of extending the life of the blacking. Also sicking a soft polymer to the hull (like HDPE) has been proven to resist abrasion by particulate.
Paul Roberts | Sat Jan 28, 2017 at 1:58am
What are your views on zinc spraying a narrowboat hull please?
Whilton Marina | Mon Feb 20, 2017 at 3:07pm
Hello Paul,An interesting question, but to be truthful it's something that we have never come across before.
elspeth soutar | Tue Mar 21, 2017 at 5:54pm
Ive been reading about aluminium hulls and wonder if I need to black my hull after I have had it thoroughly pressure washed. Some seem to say that Aluminium hulls dont need blacking but the boat I am buying has been blacked before. Do I need to do it again this year if it was blacked 3 years ago on aluminium hull?
Whilton Marina | Tue Mar 28, 2017 at 11:42am
Hello Elspeth, Aluminium hulls do not need painting except below the waterline or where anything is touching the hull surface. Bare aluminium forms an aluminium oxide coating on its surface that creates a barrier and prevents the metal from corroding. If the boat has already been blacked, from a cosmetic point of view you may wish to black the hull again, especially as it will need blacking below the waterline.
Ahh Kid | Wed May 31, 2017 at 6:17pm
Hello, is it possible to get the blacking in a grey colour? due to I'm planning to have the top of my boat painted in battleship grey.
Helen Art | Mon Jun 5, 2017 at 8:05am
Does a fibreglass hull need Blackened? Is it basically a process to stop anything sticking to the boat from the water? What would be the best option if a fibreglass hull were to be Blackened? Thanks so much!
Whilton Marina | Mon Jun 5, 2017 at 2:37pm
Hello Ahh Kid, there may be a product on the market that is a colour other than black that could be used instead of blacking on a narrowboat, you would need to do your reseach about this as we are not aware.
Whilton Marina | Mon Jun 26, 2017 at 11:17am
Hello Helen,Fibreglass boats are not blacked, they are firstly primed with a special primer that is suitable for an antifouling coating to be applied. This effectively stops weed growth from attaching itself to the hull. Antifoul is normally applied every couple of years.
Phil B | Sun Aug 6, 2017 at 8:18am
I have a permanent mooring, and in 6 months, have only done 8 hours of cruising. If this is similar at the end of the first 2-3 years, will I definitely have to have it blacked then, or can I wait a bit longer ?
Whilton Marina | Mon Aug 21, 2017 at 4:16pm
Hello Phil BThree years is the recommended time for narrowboats to be blacked regardless of how much they are used. This is because the boat is sitting in water. Which causes rusting on the waterline.
Keith Yeandel | Thu Sep 21, 2017 at 1:28pm
Can International Intertuf be applied over a 2-pack epoxy above the waterline?
Whilton Marina | Mon Sep 25, 2017 at 1:12pm
Hello Keith, We recommend that you speak to the manufacturers of International Intertuf to ask them if it can be applied over a 2 pock apoxy coating on a narrowboat hull.
Ayesha walker | Tue Feb 13, 2018 at 11:31am
If you only have your boat drydocked when blacking how are you able to black the base , as you would not be able to get under the boat in a dry dock? Many thanks
ANDY H | Wed Apr 18, 2018 at 4:19pm
Hello, I am buying a secondhand steel narrow boat in May.The dry dock and surveyor are booked.The boat comes out of the water on the Saturday and i will pressure wash it straight away to stop mud ,weeds etc drying on.However the surveyor is not coming until Monday and doesn't want any blacking put on until he has finished.Should i apply anything to the bare metal to stop rust forming over the weekend,such as a rust converter?
Whilton Marina | Mon Apr 23, 2018 at 4:11pm
Hello Andy, You don't need to apply anything to the metal once the boat hull has been pressure washed. The boat will be fine until the surveyor has finished his survey and at that stage you can apply the blacking.
Alan Vickery | Wed May 23, 2018 at 12:20am
Hi, is there any need to anti foul over the black 2 pock paint, my barge will be lifted into a saltwater river for a few weeks before going into a fresh water canal? Thanks
rosie | Sun May 27, 2018 at 2:38pm
Hi I had my boat blacked last June and I noticed in April that an extensive amount of rust was appearing on the waterline. Can anyone advise me on this?Rosie
Whilton Marina | Tue May 29, 2018 at 4:36pm
Hello Alan, we have checked with a local surveyor who confirmed that is the boat is only going to be in saltwater for only a short period of time, no harm will come to it.
Whilton Marina | Tue May 29, 2018 at 4:39pm
Hello Rosie, (two comments above) Did you cruise the canals during icy periods? as this can strip back the blacking on the waterline. We suggest if you are worried get the boat out of the water to get the hull checked.
Cheryl | Fri Jul 20, 2018 at 12:04pm
Is blacking a boat the same thing as anti fouling or do both things need doing.
Whilton Marina | Tue Jul 24, 2018 at 3:35pm
Hi Cheryl, Narrowboat hulls require pressure washing and blacking approximately every five years.Antifouling is used on fibreglass and seagoing boats to protect from erosion and to slow the growth and/or facilitate detachment of subaquatic organisms that attach to it. Antifouling is not usually used on narrowboats.
whilton Marina | Wed Jul 25, 2018 at 11:05am
Hi Cheryl, the above answer to your question should have said Narrowboat hulls require pressure washing and blacking approximately every 2-3 years using Bitumen and 5-6 years if using Two Pack Epoxy.
Victor Vectrix | Mon Aug 27, 2018 at 12:54pm
I have discovered that permanently keeping my narrowboat out of the water prevents rust. I recommend readers try this as it saves a lot of money on blacking.
Whilton Marina | Tue Sep 11, 2018 at 12:53pm
Hello Victor.. that's a novel way of thinking about narrowboat blacking! However it's not an option if you want to actually use the boat for cruising the waterways which you won't be able to do with it out on the bank.

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