Sailtimer wind vane & rotating mast...

[Lieu Daze]

Haven't been on for a bit and sorry I missed the group at the Toronto Boat show this weekend, try and get it together next year for sure. I was there today with the intent of checking out the Sailtimer wireless / solar wind vane which looks like a great product to hook up with the iPad...until I remembered the issue of the rotating mast.

Don't want to open a can on the potential of a fixed mast head system, seen the threads, but just wondered if anyone has hard data on how much you actually get out of the mast rotation as opposed to locking it down straight, (search doesn't come up with anything apparent). If it's minimal then for the basic cruising we do I would consider it.

JR

[mastreb]

An easily rotating mast gives about 1 knot of extra speed, and is especially beneficial in moderate winds around 10 knots. I've pinned the mast and taken anemometer and GPS readings to prove it, because I seriously considered fixing the mast so I could put my Maretron WSO100 anemometer atop it.

Four ways to do wind:

Easiest:
Watch the other sailboats. Set your mainsail to match the ones making the best speed on your heading. This is free, but it does require other sailboats running on your heading.

Easy:
Get a windex, put it on your masthead. Shows the apparent wind, which is what you need to set your mainsail. $40, hard to beat.

Medium:
I've had a wind instrument for 18 months now on a temporary Shakespeare jackstaff 6' feet up on the bow, mounted to the pulpit railing. Works just fine there except when you're dead downwind, but I haven't committed to the location so I put it on and run an NMEA2000 cable through the deck hatch when I want instrumentation. It's temporary. But it works and it allows me to handle all my instrumentation needs. I've decided not to make this permanent because I'm eventually going to...

Hard:
The only permanent masttop solution for an electronic anemometer on a Mac 26M is the following:

Mount a hinge at the forward mast head. Mount your anemometer on that hinge, and then run a 2nd forestay from the forward part of the hinged assembly down to the bow. The forestay will keep the anemometer pointing forward and the forward mast location is the same point of rotation as used by all the stays. Also you'll get a backup forestay in case your main fails. There's also the running of the NMEA2000 cable unless you've got a wireless system.

The aft mast bracket location doesn't work. The mainsail dumps wind into it on a beam reach, which is exactly when you want to know the wind.

[u12fly]

I'm working on a solution to this problem... Hope to be able to post details soon.

Chris.

[BOAT]

Would it do any good to mount on the spreaders?? They do not turn with the mast.

[u12fly]

Would it do any good to mount on the spreaders?? They do not turn with the mast.

No... You need to be at the top of the mast, not only that you need to be forward of the mast as well. I've done a lot of experimenting and there is an upward wash that comes off the main sail requiring any "accurate" wind speed and direction to be made in front of the mast by at least 8 inches. Luckily the is a fractional rig so the front sail does not affect a wind system mounted at the very top of the mast.

Chris.

[Crikey]

There are many electronic alternatives, mostly pricey, but here's a couple for starters:

http://www.navstore.com/detail.aspx?ID=1543

http://www.southernseasmarine.com/ssm/n ... rc-box.htm

If I could find something for a couple of hundred, I'd go for it.

Ross

[Lieu Daze]

I knew "not opening up a can" on this forum is always a stretch but as usual great input from you guys.

Meant to try it for years myself but if locking the mast means a 15% or better loss in performance then the idea is obviously out.

Agree mastreb...I've been using the easiest method for 3 years now, using tells on the shrouds and trimming for best speed with Bills, (Boats4Sail), tried and true cassette tape for extra telltales on the leech since I broke 2 of the $40 vanes with the extra rigging up & down for travel.

Right with Chris as well...you have to be at the top of the mast to be effective and true. If you're going to spend money on an instrument like this you want it to work as it should. Most of the new catamarans have rotating masts and use the mast compensator systems you mentioned Ross. Like you say, expensive.

This wireless system is just an enticing toy because it has some great features such as tracking and building boat specific polar equations to give you a great accurate VMG to get to an upwind destination on the perfect tacks. I'll likely go back to my 60hp equation to getting there on time if up wind.

I did email the manufacture and they didn't have a viable solution short of placing it on an alternative location and sent this pic of a client in Sweden with it actually on the shrouds. I believe it would get iffy performance here as well from foresail interference.

JR

[BOAT]

What if you welded a pole to the top of the spreader yoke that was so tall it was higher than the mast and put the wind thingy on that?

[BOAT]

And if you think that little pole is too long and would flop too much you can also put little mini stays on that pole too. (In case you were gonna ask)

It would be like a little mini mast atached to the spreader yoke

[1st Sail]

Two thoughts. Both use a mast head mounted metal plate sitting on a bearing similar to the BWY mast foot bearing. A larger diameter thin bearing approx. the size of the mast head plate would increase stability.
1. the plate extends forward of the mast 8in. a recommended previously. Plate is t-shape extending out from the mast a few inches. Stay lines are attached to the port and starboard arms and attached under slight tension the end of the stays. This would be the easier choice for those of us who trailer and you could bunge the stays to the mast.
2. Some M owners have installed a back stay for better sail control. Same relative design as #1 but the bearing mounted plate extends behind the mast to stern with a line yoke line attached to the starboard and port rear stantions.
The back stay design could be rigged with the same 1/4" braided line we used for a topping lift and could be easily tensioned as needed. Plate extend 8in forward per recommended design. The back stay design would require less load due to the vector angle of the back stay. It could be tied off the the mast arch for testing.

For trailering a quick disconnect between the wind vange and plate would prevent damage from shock load and high winds while traveling.
Feel free to hamemer on this one. FWIW

[u12fly]

...
I did email the manufacture and they didn't have a viable solution short of placing it on an alternative location and sent this pic of a client in Sweden with it actually on the shrouds. I believe it would get iffy performance here as well from foresail interference.

JR

JR: Who makes the Trimaran in the picture... I would agree not a good place for the wind inicator.

Chris.

[Lieu Daze]

Hey Chris...the trimaran is a Dragonfly. There's a few threads on here about it but it's worth a You Tube look, very cool, very fast and trailerable rocket. Not much interior space inside but by the looks like quite a ride. Still waiting for one of the mod lunatics here to rig a Mac with the same.

1st Sail & Boat...you're onto something with the mast head. I had a vision of your bearing mounted T plate idea that was tied down both sides to the spreaders instead of fore or aft. That perhaps with a connection from the front of the plate down to the upper shroud bracket might take all the potential twist out of it?

Let us know if you've got something on the go....

Jim

[BOAT]

I think it's just too far from the spreader yoke to the top of the mast - it would be just too much crap in front of the mast.

I'm thing about it - I'll keep my brain trying to figure it out.

[1st Sail]

Boat,
maybe I confused everyone. I'm thinking of running stays from the tip of the spreader end to the top of the mast plate. The bearing plate is this case is t shaped. With the stays attached to the ends of the T. The body of the T extends forward of the mast 8in. The bearing is mounted at the intersection of the 'T' with the body to hold the wind vane in front of the turbulance. Nothing attaches to the yoke.

[Crikey]

I suppose one of each on opposite stays. Probably cheaper than an electronic compass compensator, and made switchable for your point of sail. Both on for running.