Chain Plates, shrouds

[abbott013]

I have two U bolts that carry my shrouds, they are 3/8 stainless. First Question, has anyone any ideas on removing them, they are seized solid. i have tried using a bar and gentle heat but can not get them to move. last resort is to cut them and wind them out. Second Question, Last resort, does anyone know of a supplier that can supply me 3/8 U bolts or 9mm, i have looked at 10mm U bolts but with space being very tight i do not think i will get nuts on.

 

[fluffc]

3/8" is almost exactly 10mm.

 

[Norman_E]

10 mm is actually less than 20 thousandth of an inch bigger than 3/8 inch. Next size down will be 8 mm which is almost exactly 5/16 inch and would not be an acceptable replacement if the original was correctly sized in relation to the forces involved. In replacing U bolts the radius of the bend needs to be the same, so that the hole spacing is unaltered.
The 10 mm nut size is just over 1/16 th inch larger across flats at 17 mm (0.669 inch) against 0.601 inch for a 3/8 inch BSF nut. BSW (Whitworth) nuts were in fact originally all one size larger than the BSF equivalent i.e. 3/8 inch BSW nut was 0.710 inch, however BSF sized nuts have been standard for both thread forms since World War II.
As an example of approximate safe working loads a 3/8 inch BSF bolt stressed to 3000 lbf/sq.inch will take a load of 228 lb. A 5/16th BSF bolt at the same stress, only 152 lb (about 67% as much). This explains why a drop from 3/8 inch or 10 mm to 5/16 inch or 8 mm would be a bad idea.

 

[anubis]

Baseline Marine may have them.

 

[abbott013]

Thanks Artic

 

[dickh]

Try ebay - the seller 'stainlessdirect' has them - see:- http://cgi.ebay.co.uk/NEW-10mm-x-90mm-U-...oQQcmdZViewItem

He has an excellent range of all things stainless and is excellent value.

To remove the original, after you've removed the nuts & washers you should be able to lever them upwards gently with a jemmy bar resting on a lump of wood to protect your deck.

Also try wichard for U bolts, very good but expensive.

 

[William_H]

As an alternative you might find that a really heavy saddle with 3/8 holes would enable you to use plain 3/8 bolts. yes if you can't get them free then cut at the U and try to unscrew each one separately.
good luck......... olewill