Jonathan, I concur that determining whether you have a conduit is a good idea.

If you have conduit, the foam won't make it harder to pull wires through the conduit; no problems are created.

If you foam the mast with bare wires, you will find that pulling new wires in should you ever need to add something or replace something will be very difficult, or nearly impossible. (I dealt with something like that once, and hope to never again!)

David Tyler wrote:

The conduit itself needs securing, or it will bang about. This is something that I omitted to do before stepping the mast. Now I will have to go halfway up the mast, drill a 5mm hole, spray in a mist of water and then insert the straw of an aerosol of polyurethane foam (water is what cures a one-part polyurethane). Polyurethane is long lasting and will adhere to almost anything. A good big plug of polyurethane foam should fix that pesky conduit.

Jonathan Snodgrass wrote:

Thank you for that David.

The cables and/or conduits inside the aluminium alloy masts on Lexia make a frightful noise.  I have been wondering for some time on how to tackle that.  

The prospect of having to lift two large masts to rework the innards does not bear thinking about.  

I had therefore been pondering whether one could drill a hole in the cap on the mast and pour down small balls, presumably something like polystyrene pellets to fill up the mast.  (If the cap was big enough and one made a big enough hole then maybe table tennis balls !)  The repair the hole in the top of the cap.  I would guess that weight and moisture would not be issues.  

However, maybe you have provided me with a more viable alternative.  

I suspect that I would have to inject the foam in more than one place.  However, perhaps I should start with one injection in each mast and see if it stops the noise or not.  If it only reduced it the noise one might then be able to presume that one was on the right lines.  

Would you have any reservations on a me putting a number of 5mm holes?  It might be sensible to stagger them round the circumference rather than in a straight line.  

Does a 5mm hole cause any significant weakness?  I would guess not but would be open to advice from anyone.  I presume that one should try not to make  holes near the deck partners.  I was at one time advised that if after drilling a small hole one filled it with a monel rivet then it was as strong or stronger than before it was drilled.   

All suggestions welcome.

One thing to note about these masts is that they are laminated with epoxy, not polyester. When I was researching this idea I used US wind loading ratings for comparison, the manufacturers all publish those. Those standards aren't relevant to sailors but are useful for comparison. The Whatley poles seemed far superior in weight, stiffness and ultimate strength, and they are the only ones I'm aware of that are made with epoxy resin, which may be at least part of the reason they are more rigid.

[Sako started a new topic for this. Moved it here and inserted links. Brian.]

Big nylon cable ties, put 3 together in a circle (120 degrees) and cut them slightly longer then halve the mast diameter. Repeat this every meter or so.