Advice for boat repair

[jaston10078]

Tldr... Does anyone know where I can find half round flat wider than 50mm?

**Please see attached drawings**

Hi everyone, I'm new to the forum. I hope that some of you might be able to help. I'm not a welder.

Our narrowboat is in need of some work below the waterline.

On the 6mm side plates of the boat are 'rubbing strakes' above and below the waterline.

These strakes are 50mm wide D profile flat bars welded to the plate. It is common practice to weld fully at the top of the strake but only tack to bottom at regular intervals.

This allows water between the strake and the plate leading to pitting which is what has happened in our case along the length of the plates right below the strakes.

The common method for fixing this is to remove the strake and weld new plate along the the affected area plus welding a new strake onto that. This is due to the fact that removing the old strake results in damage to the plate from grinding.

I've seen the results of this type of repair and it doesn't look great and would no doubt affect the value of the boat.

My Idea would be to source extra wide d profile (half round) flat bar and once the old strake is removed, fill the pits with weld and weld the wider profile to the plate, covering the grinding damage etc.

I'm having trouble finding any Half round/d profile any wider than 50 or so mm.

Does anyone know if this kind of profile or similar exists as a stock item in the UK. Or perhaps does anyone have any other suggestions?

Many thanks,

James

 

[bricol]

How thick does it need to be - if you look for "half round square edge" that comes in at 2" wide - but isn't particularly thick

 

[gaz1]

my reference would be to weld 1" angle iron and then plates as the repairs will only be to the angle iron wear plates after that but its all down to cost

and most just want to weld a plate all the way down the side of the boat

but im not a boat builder but do understand wear plates enough

 

[dieselsamurai]

Ive never seen convex bar above 2" (51mm) you might have to settle for just 60mm flat bar to achieve what you want

 

[Ian X]

Handrail

Handrail - Length 6000mm 60 x 16mm Convex Bar. Buy online or call to order. Free delivery on orders over £150.

www.fhbrundle.co.uk

You have a fierce job of work on your hands cleaning off X metres of weld from the upper edges.

 

[addjunkie]

@spaffmonkey does such things for a living, though not seen him posting for a while. Suspect its only tacked underneath as welding overhead is harder.
Id not worry too much about the nice convex bar. Just go over it with say 75x 10 or what ever-you choose, then knock the sharp corner off with-a flap disc when done.

 

[dieselsamurai]

@spaffmonkey does such things for a living, though not seen him posting for a while. Suspect its only tacked underneath as welding overhead is harder.
Id not worry too much about the nice convex bar. Just go over it with say 75x 10 or what ever-you choose, then knock the sharp corner off with-a flap disc when done.

I'd do this , so much cheaper and no one will notice

 

[bricol]

40 ft boat . . . that's a lot of edge knocking off . . .

Actually, it’s lot of welding too . . .

 

[jaston10078]

Hi all, thanks so much for all the replies so far. Will reply properly later as I'm tied up a bit now....

Fyi 53ft boat... A really big job but one the yard is used to doing.

Also, I think that 60mm wide bar linked above is wrought Iron... I'm unsure how the boat yard would feel about that. I'll have to check but good shout!

The idea would be to do this in stages ... Worst areas first followed by less affected areas when boat is lifted every 3 years for blacking.

 

[Agroshield]

Also, I think that 60mm wide bar linked above is wrought Iron...

What do you understand by 'wrought iron'? When was the last time (to the nearest 50 years will do) that wrought iron was commonly available?

 

[jaston10078]

Hi Agroshield,

Just going by the website including that in the "Wrought Iron Components" section of the website.

I'm assuming by your protestation that this is a historic term used to mean something different nowadays. I apologize for my ignorance, I'm just here for advice.

If it's made of the same stuff my narrowboat is made of then this could very well be the solution.

Again, forgive my ignorance but am I right in thinking that this would be cast? If so, does this have a bearing on it's application with rolled plate?

Thanks

 

[Agroshield]

Just going by the website including that in the "Wrought Iron Components" section of the website

It is best to read the catalogue as marketing spiel rather than a technical specification. Perhaps a longer-winded but more strictly correct description would be "hot rolled mild steel components shaped to replicate items that would have originally been made from wrought iron". Does not trip off the tongue so well...

There is another company, called DC Iron, who sell much the same stuff as Brundles, so they might also be a possibility.

 

[jaston10078]

Thanks very much for clearing that up for me.

I'm going to see if the boat yard could make this work.

 

[George A2Y]

Even more welding but what about two (half round) straps 30+mm wide, if available.

 

[jaston10078]

Thanks again to everyone for your replies.

As mentioned before we plan on doing it in sections. The section in greatest need is only actually about 2 meters long and is what we'll do first. Thankfully the majority of steel plate is currently unaffected. However, in the fullness of time it will all need to be done.... even the section on the plates that form the diesel tank. .

I'll see if the yard is willing to give the 60mm handrail a go.

The suggestion of regular flat bar of 75mm or so will be my fall back plan as this will be easier to get hold of and will definitely be wide enough to cover the affected area.

 

[jaston10078]

Even more welding but what about two (half round) straps 30+mm wide, if available.

I did actually think about that. Sizes up to 2" are readily available

 

[Ian X]

I did actually think about that. Sizes up to 2" are readily available

Yes, doubling up might be an option, possibly a cheaper option as 50mm is common, 60mm less so.