mast spreaders

[tckearney]

Hi all,  I have just had a mast survey carried out and the surveyor mentioned the upper stbd mast spreader fixing holes are worn (he wobbled the spreader, that's all) .  I have just checked and the hole sizes in the aluminium spreader extrusion  are exactly the same as the port spreader.   The spreader fixing pin that goes through the casting and the spreader is  fine with no wear.   I must admit the pin does wobble a bit in the spreader holes, if it is inserted without the spreader casting.   So my question is, has anybody ever sleeved the holes in the spreader extrusion?  it looks very simple if you have a lathe and good stainless steel. 

[Yngmar]

Which way do the spreaders wobble? Up and down is fine (they will be held by the wire). Fore and aft not so good, although I think a small amount is normal.

[tckearney]

Hi Yngmar  a  bit of both.  pin is 14.97mm  hole is 16.2mm.  I have found SS pipe on internet 15mm internal and 16.5mm external, sounds perfect.  I'll do a trial and post results.     

[PEA-JAY]

Stainless steel corrodes Alluminium. Fixing holes will increase in diameter so fittings become loose or tear out altogether. It’s important to use monel metal rivets

[sy_Anniina]

"Stainless steel corrodes Alluminium"...


Yes but... in normal situation we use stainless bolt / clevis pin to fasten aluminium spreader to aluminium casting on mast. Is this the reason the holes may grow?

BR,
Tommi
s/y Anniina

[tckearney]

As I understand it Stainlessm steel and Aluminium in saltwater conditions generates less than .25v between metals , which when I worked in the industry, (many many years ago) was within the Limits set out by MOD

[Mirror45184]

Pin to hole clearance sounds about right for the situation, running fit. If you sleeve with the SS tube as proposed the spreaders will be very difficult to assemble. The upper spreaders are not heavily loaded, fairly shallow deflections. I would first get someone to check the rig tensions before putting sleeves in place and potentially creating an issue. The rig does flex and so some movement is required.
Cheers