Imperial U bolts

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doug748

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I probably should replace my shroud U bolts. They are straight, imperial sized from 3/8th dia stainless with a hole centre of 2 1/4in. Originally manufactured by Main Marine. They have a fixed, welded deck plate.

Does anyone have any suggestions for suppliers?

As an alternative I might consider having them ND tested, anyone any leads or experience with this?
 
doug748 said:
I probably should replace my shroud U bolts. They are straight, imperial sized from 3/8th dia stainless with a hole centre of 2 1/4in. Originally manufactured by Main Marine. They have a fixed, welded deck plate.

Does anyone have any suggestions for suppliers?

As an alternative I might consider having them ND tested, anyone any leads or experience with this?
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I looked for U bolts of that type recently and did not find any with imperial dimensions. There seems to be no standard size, but 50mm centres is common (as are M8 threads, close to 3/8"), such as in the Wichard range. What I did find is that those from "marine" suppliers such as Wichard and Seasure are relatively expensive compared with industrial suppliers, although many of those are 304 rather than 316.

Suspect you will have to get them custom made if you want to keep the same centres - although Rogers might be a source for the original.

s
 
Thanks for all the suggestions which I will follow up.

I have E mailed the Roger's yard Tranona. I may need a stiff drink when the price comes back.
 
I had to do this for the U Bolts on a Jaguar 27, although only 5/16" diameter not 3/8". I had to replace them as I sheared off one of the nuts and when removed for replacement there was some serious crevice corrosion so I replaced all of them. From memory I used Wichard 'U' bolts which were near as dammit identical. Could you fill the existing holes with epoxy and then re-drill for a replacement U bolt? Can a loose plate be welded to the stems to replicate existing? I suspect loose plates would be just as good with sealant.
 
I am not keen on altering the deck to suit new bolts plus there are heavy stainless knees underneath and I prefer to leave these as they are.

The old U bolts are not bad but I detect some small imperfections and it is policy to replace them if I am rebedding anyway. The marks may be scratches or inclusions in the original weld, I will consider seeing if I can polish them out as a fallback position.

Good point about loose plates. The welds keep water out nicely and support the fitting but if any cracking occurs it can be propagated through the bolt itself, so a mixed blessing.

The original builder can supply replacements at a cost.
Think of the most outlandish price you could for a pair of U bolts, add VAT and carriage, double that number and you would be somewhere near it. I am now looking at having new ones made.
 
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Doug, I kid you not about u bolts r us.co.uk. You do not need to buy u bolt with a welded strap, use a strip of 316 and 2 extra nuts as I do. U bolts r us supply in 316 many sizes and configurations.
 
third engines said:
Doug, I kid you not about u bolts r us.co.uk. You do not need to buy u bolt with a welded strap, use a strip of 316 and 2 extra nuts as I do. U bolts r us supply in 316 many sizes and configurations.
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If you check their website they are all metric and different centres from the ones needed. If one is going down that route then the ones from Baseline or Wichard are far superior and will be a fraction of the price Rogers will want. 40mm spacing with M8 are around £7 and 50mm with M10 are £11 at Baseline. These have fixed plates and long enough legs to go through decks and backing plates underneath.
 
Tranona said:
If you check their website they are all metric and different centres from the ones needed. If one is going down that route then the ones from Baseline or Wichard are far superior and will be a fraction of the price Rogers will want. 40mm spacing with M8 are around £7 and 50mm with M10 are £11 at Baseline. These have fixed plates and long enough legs to go through decks and backing plates underneath.
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Sorry, you have that wrong. they advertise imperial on the website.
 
third engines said:
Sorry, you have that wrong. they advertise imperial on the website.
Click to expand...

But not in stainless and not the width the OP needs. The only thing in common with the OPs needs is the 3/8" diameter, but that is not a big issue as M8 only needs a slight enlargement of the hole.

The spec the OP needs is in his original post and nothing from your suggested supplier meets it.
 
https://www.graphskill.co.uk/en/584...-85mm-inside-height-t316-stainless-steel.html

M10 (3/8 = 9.5(25))
60 center to center original 57mm
Only need a deck plate welded on which anyone with a GTAW welding machine could do.
With a bit of ingenuity I am sure these could be squeezed down to 57mm center to center. Squeeze it round a socket or a bit of steel bar 47mm od and spread the ends again back to 47 id (57center to center)
 
Result, well spotted Slapper, that is as near as I can expect to get

May just be a tiny bit short (the originals are 4in top to bottom) but I am sure I can work with it. I will see what the quote is for 4 exact copies to be made up, then decide.
 
That looks better. Note they have deck plates available as well, including a slotted one which could be welded on. Is the threaded part long enough (35mm) to go through the deck and does this leave the top of the U at the same height, or close enough so you have enough adjustment in the rigging screws.
 
Yes, I think it will be doable. I will just have to take an accurate measure of the deck and rigging to make sure.

I will go ahead with the quote because there are a number of handy fabrication shops nearby and (being idle) if I can source something that is a straight fit I don't mind spending a bit more cash - to a point.

Thanks all, I will report back.
 
Well, Graphskill are good people but the rolled thread means the stock bar is well under 3/8th in so no good. Next size up is 12mm, too big.

I will be looking at having them made up from 10mm bar and will have them cranked 10deg which should make a considerably stronger job. £40 a piece but still cheaper than the original boatbuilders.
 
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