Install wind sensor with mast up?

[rfkneller]

Want to replace the wind sensor at the top of the mast. Wondering if anyone has done this successfully with the mast up. My boat is a 1986 O'Day 35. Have to run a new cable as well as mounting the wind sensor.

[Fiveslide]

Yes, I have. Do you already have a messenger line in the mast? If not, you'll want to pull one thru with the old cable.

I fed the cable in the top with the messenger line pulling it down. It got hung up a few times but we backed up a bit and started feeding it again.

[rfkneller]

Did you do it with mast up?

[Fiveslide]

Yes. Certainly try it that way. Worse case, it fails and you unstep the mast and do it on the ground.

[Frankly]

Replaced the wind sensor on two different ships with the mast up (49 ft and 45ft). Pulled string up removing the old cable and new cable down with the string. Got to feel comfortable working at the summit but really NBD if you think a couple of steps ahead. Make a good tight splice and a little liquid soap at the splice (only get one shot). Most Isomat mast sections have a PVC chase(s) installed in the fwd areas of the mast.

[seandepagnier]

When the boat rolls from waves, the sensor at the top of the mast gives invalid readings especially in light winds.

[boatman1]

It can surely be done with the mast up, though not as efficiently as the mast laying horizontal on the ground. I know of at least one boatyard with a "manlift" for performing work on the mast truk. It would be worth calling around to boatyards in your area to see if any have such equipment: it really does make for a quicker and safer install.

[OS2Dude]

We installed a new wireless instrument last year. I hauled my brother to the masthead and he mounted an aluminum plate that we had tapped to mount the instrument on. It took a couple of trips (Once to measure then again to mount) but not that difficult. In a wired setup, be sure you have something taking the weight of the cable besides the connector. If it is a NMEA cable, you can get terminating 'T' for use there.

[Dougtiff]

If you do not have an old cable to pull down, you can use light fishing line, poke it in the hole at the top and have someone put a vacuum cleaner nozzle at the hole at the bottom of the mast, it will suck the line down, then you can attach a stronger line to the fishing line and pull it down, ect.

[Deltasailor]

If you have not got a mouse line or the previous wiring it is still no problem.
Just feed the new cable down the mast, it takes time as sometimes you need to pull it up a bit when it stops falling. Look through the halyard holes and with a length of stiff wire fish the cable out. The final exit of the cable may take a bit of thought but can be done.

[barnakiel]

I normally use the old wire as a lead for the new one. But you MUST make the connection smooth and strong. This is why it is easier to pull up from the bottom up.

It is 100% normal to do it without unstepping the stick as long as the boat is stable enough (I think all 30+' keelers are).

b.

[Sailorbob8599]

Originally Posted by boatman1

It can surely be done with the mast up, though not as efficiently as the mast laying horizontal on the ground. I know of at least one boatyard with a "manlift" for performing work on the mast truk. It would be worth calling around to boatyards in your area to see if any have such equipment: it really does make for a quicker and safer install.

Ha! you beat me to it Boatman, I too used a man-lift to work on my mast-head.

My boat is equipped with a tabernacle allowing me to lower the mast quite easily, but it is time consuming and one needs to remove the mainsail and boom, as well as detach and re-attach standing rigging. So yes, I fully agree.Not only is it the safest way to work up there but in my case, it was also the quickest.

From a safety point if view, every time one raises or lowers the spar there is always the possibility of having an accident.

It cost me $100 Cndn for the service, and it came complete with the owner/operator. The job took less than an hour to complete and I didn't need to re-tune my rigging.