How to repair a dent

[tove]

My boat was hit earlier this afternoon by a Canal Boat Club boat which had lost control below Newbury lock. It's left a pretty nasty dent in my bow. See photo. I've been in touch with the local wharf where these boats are run from and they're being pretty helpful about it.

Right now, I'm more concerned with how you repair something like this than who's going to pay for it. I'm assuming that it's possible to grind the paint off and infill it with some sort of body filler. Then smooth it off and repaint. The dent must be less than a centimeter deep. I have no experience of these sort of repairs. Please tell me this is do-able.

[Chris Lowe]

Find a good car body man with a decent slide hammer

[booke23]

It must have been going pretty quick to cause that sort of damage. Can you see the back of the dent from inside the gas locker?

If not, then a panel beater could probably weld rods on it and slide hammer the dent out. Once the welds are ground back and the area properly repainted, you won’t even be able to see where the dent was. 

Edited April 24, 2022 by booke23

[nicknorman]

Yes I think you need to get the worst of it out by un-denting it, then use a small amount of filler to finish it off. Filling the entire thing with filler isn’t a good idea due to the differences in expansion rate with temperature for steel vs filler, and of course the filler will be a sitting duck for any future impacts.
Or you could just live with the battle scars, and get a sign writer to embellish it with “Canal Boat Club did this ->”. These days body shaming is off-trend, celebrate what you have!

Edited April 24, 2022 by nicknorman

[Tracy D'arth]

Very expensive to invisibly repair this damage. You will discover that the distortion is over a far bigger area than it appears until you gloss paint it when it will look awful.

 

Its not a simple dent, the metal will be stretched and when it is beaten back it will need shrinking. It will need heating to beat it out, a 2 man job, then heating and quenching to shrink the excess metal back into line.

Then grinding flat, and building up with many layers of paint.

 

Don't accept a filler repair, it won't last.

 

Canal Boat Club will need a fresh cheque book for this job.

[ditchcrawler]

When it happened to a friend they chopped an oblong out and welded a new piece in its place, they didn't attempt to knock it out. Looks almost identical.

 

[beerbeerbeerbeerbeer]

5 minutes ago, ditchcrawler said:

When it happened to a friend they chopped an oblong out and welded a new piece in its place, they didn't attempt to knock it out. Looks almost identical.

 

That was going to be my suggestion.

I’d guess trying to pull a dent out of 6mm(?) steel while not impossible would be a lot of work and would never look right. 
Perhaps easier or more practical to cut out and replace. 
 

What happened were you tied up waiting to enter and the boat came out and hit you?

That’s another lock where the river comes in from the side isn’t it?

[MtB]

3 hours ago, Tracy D'arth said:

Very expensive to invisibly repair this damage. You will discover that the distortion is over a far bigger area than it appears until you gloss paint it when it will look awful.

 

Its not a simple dent, the metal will be stretched and when it is beaten back it will need shrinking. It will need heating to beat it out, a 2 man job, then heating and quenching to shrink the excess metal back into line.

Then grinding flat, and building up with many layers of paint.

 

Don't accept a filler repair, it won't last.

 

Canal Boat Club will need a fresh cheque book for this job.

 

 

I agree. The suggestions to use a slide hammer are useless as slide hammers are for use on 1mm think car body panels, not the (probably) 8mm steel just there on your boat.

 

I'd say all of my boats have similar-sized dents somewhere though. As Nick says they are battle scars and they don't affect the handling. They are proof you actually use your boat..... 

[Tracy D'arth]

Cutting out and piecing in that area which is where the bow was pulled round is a poor option. The rest of the plate will distort as the piece is cut out due to the stress in the steel.

Narrow boat hulls are not stress relieved after pulling and welding, they contain massive stress points, the bow in particular.

6mm steel plate needs heat and a substantial backing dolly used outside with  a heavy hammer inside to remove the dent as fast as possible with the minimum of blows otherwise more stretching of the panel will occur.

Ideal guy for this job would be a boiler maker.

[john.k]

I used to fix this kind of damage every day at the sandblasters (in customers new work) ....Id do it cold with a heavy dolly behind the dent ...work the dent out from around the edges .....PS heavy dolly is 50 lb or so.......never hammer a dent from the raised side ,the the metal will stretch and form a bubble,needing to be shrunk,which will burn the inside .

[Tony Brooks]

When I bought the boat is had  aver similar but larger dent. I used a body shop hydraulic ram kit between the weld between  hull side and cockpit floor using something to spread the load and the dent to push it out as best as I could. There was no way either the mooring hammer or a sledge hammer would make any difference. They just bounced off and I did not have enough elbows to use the hammer and hold a dolly in place. Then sand out the rust, prime and one top coat. Fill with body filler and sand back to profile and then do the proper paint job.  You may ask why paint before filing and the answer is because body filler is porous and I have seen too many car repairs where rust has forced body filler off. I am sure it would have been far easier if I could have got sufficient heat into the metal but that would have wrecked a very large area of paintwork, both in side and out.

 

Epoxy (rather then polyester) filler might not be porous but it is more expensive and I dd not find it as easy to work with.

 

However I think that Canaltime need to put this right and I would not be   happy with more than  a skim of filler.

[Alan de Enfield]

9 hours ago, MtB said:

They are proof you actually use your boat..... 

 

Or, CM where it is not a good idea to moor.

[David Mack]

13 hours ago, Tracy D'arth said:

Very expensive to invisibly repair this damage. You will discover that the distortion is over a far bigger area than it appears until you gloss paint it when it will look awful.

From the reflections in the paint it looks to me as if the distortion extends from the rubbing strip below almost to the top of the cant, and a similar size horizontally. So that is a lot of plate to flatten.

 

13 hours ago, Tracy D'arth said:

Canal Boat Club will need a fresh cheque book for this job.

And when they hear how much it is going to cost they will be a whole lot less helpful.

9 hours ago, Tracy D'arth said:

6mm steel plate needs heat and a substantial backing dolly used outside with  a heavy hammer inside to remove the dent

But is there room to swing a hammer inside (what I assume is) the gas locker?

4 hours ago, john.k said:

Id do it cold with a heavy dolly behind the dent

Or to get a dolly in there and hold it against the back of the dent?

 

I think in practice this is unrepairable, and the OP will have to live with the dent. Canal Boat Club could at least pay for the paintwork to be redone.

[SteveLevis]

We had a similar problem on our boat and we went with cutting it out and welding in a new piece..

[booke23]

You'd be surprised how thick steel can be straightened with a slide hammer. They use them on vehicle chassis. The principle is that you are concentrating the blows in a very small spot, a bit like hitting a pin punch with a sledge hammer only in reverse. However it requires a very skilled person, is very labour intensive and is possibly overkill for a narrowboat which will inevitably pick up minor dings during it's life. 

[Slow and Steady]

I like the dent.

[frangar]

I’d be interested to know what part of the canaltime boat caused this…there were some up in the midlands with “bow fenders”…I use the term loosely…that could have been designed to cause damage…just a square of steel with a bit of rubber extrusion bolted to it…they often lost rubber so in effect had a battering ram…far from the fendering as required by the bylaws Id have said. 
 

I’d be mighty miffed if this was my boat and would want it repaired to look as before the incident whatever it might cost canaltime…I’d also ask for a surveyors report to make sure there isn’t hidden damage to bulkheads etc…after all you shouldn’t be paying for it. 

[nicknorman]

1 hour ago, frangar said:

I’d be interested to know what part of the canaltime boat caused this…there were some up in the midlands with “bow fenders”…I use the term loosely…that could have been designed to cause damage…just a square of steel with a bit of rubber extrusion bolted to it…they often lost rubber so in effect had a battering ram…far from the fendering as required by the bylaws Id have said. 
 

I’d be mighty miffed if this was my boat and would want it repaired to look as before the incident whatever it might cost canaltime…I’d also ask for a surveyors report to make sure there isn’t hidden damage to bulkheads etc…after all you shouldn’t be paying for it. 

The problem is that canal boat club probably isn’t responsible for the damage. The individual driving the boat is. In the same way that a hire car involved in an accident isn’t the responsibility of the car hire company, it is the responsibility of the driver. Or the allocated insurer, obviously. But despite who paid for the insurance, in law the claim is against the driver,  not the owner.

[MtB]

13 minutes ago, nicknorman said:

The problem is that canal boat club probably isn’t responsible for the damage. The individual driving the boat is. In the same way that a hire car involved in an accident isn’t the responsibility of the car hire company, it is the responsibility of the driver. Or the allocated insurer, obviously. But despite who paid for the insurance, in law the claim is against the driver,  not the owner.

 

Yes this is my understanding too. The hard bit is quite likely to be finding out who they were.... 

[IanM]

We've got a dent like that.  Just bashed it out a bit from the inside and left it at that.

 

It was a hire boat that did ours however they weren't travelling fast, just a narrow point on the canal, passing moored boats and someone on their boat fended off a moored one a little too hard and they hit us. 

 

Was surprised what a dent it caused to be honest but life is too short to worry about it.

[john6767]

our boat had a dent is a similar location when we bought it

 

 

 

When it was repainted, Rose Narrowboats cut the area out, bashed the dent out and then welded it back in.  I was not possible to just bash it out in place.

 

Post repaint.  

[Arthur Marshall]

I've got a dent in the same place (i-dent-ical?) as the photo above. I'd lent the boat to a friend and it came back with it, and now at last I know what probably did it, as he never admitted anything. I treated it as a scar of honour.

[tove]

23 hours ago, john6767 said:

our boat had a dent is a similar location when we bought it

 

 

 

When it was repainted, Rose Narrowboats cut the area out, bashed the dent out and then welded it back in.  I was not possible to just bash it out in place.

 

Post repaint.  

Thanks for this. I've sent you a message about it. Hope you don't mind.

[David Mack]

23 hours ago, john6767 said:

When it was repainted, Rose Narrowboats cut the area out, bashed the dent out and then welded it back in.  I was not possible to just bash it out in place.

Why not just weld a new flat piece in? Less work than bashing out the dent.

[john6767]

59 minutes ago, David Mack said:

Why not just weld a new flat piece in? Less work than bashing out the dent.

It might actually have been a new piece when it came to it. The main point was it was not possible to knock the dent out in place.