Laser mast- top section

Gil

Gil

Bateau Blanc
I have a problem with the top section of my mast and seek advise. I bought a new Laser top section mast last summer ( Oz) to fit my full rig and radial bottom mast sections. Fit was perfect on my full rig , and a bit snug with the radial bottom; I have happily sailed with each bottom section+top a dozen time or so this summer. Now it is Australian winter- 13-17C and humid. I can not fit the top section normally . I lightly sanded the white plastic fitting/rings and even applied silicone spray. My hypothesis was that the white plastic rings are hygroscopic and swell with humidity. 2 questions and 1 comment:
1) Am I correct with the hypothesis and Is my problem common?
2) What is the best solution? If I sand too much, fit might become loose during summer- correct ?

Comment:
I paid $280 for the section expecting aircraft specs, good materials and high quality control; this is visibly not the case. How much variation is there in mast thickness/flexibility? Is there anybody sailing with a flexible and a rigid mast depending on conditions?

Thanks
 
I would guess its the Al section shrinking. The plastic fittings are made of the same plastics as bearing materials. They should exhibit no changes with humidity. If that was the case, whenever you capsized the mast section would be stuck.

The tolerances are all over the place with old/new masts/fittings. There is a difference between the standard lower and the radial lower. The radial lowers are known to bend a lot. In order to bend that much the tube goes out of round. I helped sand my friends fittings into an oval shape to fit his bent Radial lower.
 
I'm not that familiar with the white fittings, Any chance sand, salt or gunk got in there?
if you sand the fitting too much, you can always wrap some rigging tape around the fittings, I have the blue fittings and they fit a little loosely so I tape the top fitting with a small piece of rigging tape, you want it tight enough so the top mast doesn't rotate while you're sailing.
 
Expecting aircraft specs?? LOL For $280 ROFLMAO
Nothing wrong with the materials or quality. The plastic fittings, which I think are just nylon and non hydroscopic, come out a generic size that needs to cater for variations in the internal diameter of the spars, caused by die wear, which are within tolerance.

Metal shrinks and expands with temperature, as do all materials. All alpha aluminium alloys (majority of aluminium alloys including those used in aircraft) will essentially expand and contract the same amount for the same temperature change. Only when you have dissimilar materials that expand and contract at different rates do problems occur, this isn't a quality issue, your unlikely to get any plastic that behaves similarly to aluminium.

You need to sand the plastic fitting down so that it fits during winter and if it's a big issue in summer, put some electrical tape onto the plastic to build the thickness up. IMO it's better to have a loose fit, than to bang the spars together to get them together/apart, all you're doing is damaging the rivets that hold the fittings in place and making the rivet holes large which may cause the spars to leak.

There is a reasonable chance that you've bent the spars which will cause issues with the spars fitting together.
 
You must log in or register to reply here.

Back
Top