I'm working on the assy pole mount, today. The carbon fiber ring is done. I took a good look at the front of the boat the other day and I've cut the basic mount shape out of a high quality fir 2 x 4. The sides are getting two layers of 6 ounce glass in epoxy right now. It's sitting under a 25 pound lead brick, with plastic between the sticky side and the cement...and the upper sticky side, and the brick, to keep it all from becoming One with the Driveway..
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Getting Ready for SHTP 2021
- Thread starter AlanH
- Start date
Here's a first look at the assy pole bracket. It's not assembled yet, it's just the two pieces sitting on each other. I'm 99% sure that one of the hold down bolts will have to be buried inside the body of the bracket. There isn't room to have one on each end. The little "ledge" on the left is for one bolt. I'm betting that the other one will be at the bottom of the curve in the wood.
AND...it's Windvane Installation Day!
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That looks great. Did you prepare line drawings or schematics of what the system will look like installed on the Wildcat? If you posted them previously on this thread I missed it.
See my next post!
I spent the day on the boat, fussing. I really need to clean up down below! Anyway, I laid out the assy pole with the bracket taped together and just eyeballed everything. I can't get the pole right on centerline, so I'm going to have it on the starboard side, seeing as I'll be flying off to port, most of the way to Hawaii!
With a deck-mounted pole, you have to figure out ways around "things"...like not blocking the navigation lights and retaining access to the cleats.. Ah, if only the lights were up on the bow pulpit, like the Catalina 275 Sport that's on my dock. In the end, though, I'm going to get about 6 inches more extension than the Catalina gets with it's stock Selden system, for what looks like the same length pole. I had the carbon fiber ring in backwards, so in fact that picture shows about 4 more inches extension that I'll actually have.
With a deck-mounted pole, you have to figure out ways around "things"...like not blocking the navigation lights and retaining access to the cleats.. Ah, if only the lights were up on the bow pulpit, like the Catalina 275 Sport that's on my dock. In the end, though, I'm going to get about 6 inches more extension than the Catalina gets with it's stock Selden system, for what looks like the same length pole. I had the carbon fiber ring in backwards, so in fact that picture shows about 4 more inches extension that I'll actually have.
The Windvane Is Installed!
The bits of wood it's mounted to need some paint! If it all works the way it should, I'll take the upper part off, take it home and paint it. The point where the red control lines go through the little blocks and then out to the "spreaders" on the rudder, is almost exactly right over the axis of rotation of the rudder. It's maybe half an inch in front, which is right about where I wanted it. That half-inch will provide a little bit of damping.
The bits of wood it's mounted to need some paint! If it all works the way it should, I'll take the upper part off, take it home and paint it. The point where the red control lines go through the little blocks and then out to the "spreaders" on the rudder, is almost exactly right over the axis of rotation of the rudder. It's maybe half an inch in front, which is right about where I wanted it. That half-inch will provide a little bit of damping.
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It's "reckoning" time. ...today is the day I tot up everything I've spent on the SHTP during the year. I kept a tally through the Qualifier, and was shocked to see that I was only 2% over budget. I did one update in mid-November, but $$ have been going out the door for every little thing for the windvane this month. I just finished the spreadsheet. It's a lot but not budget-busting.
There was some wind today, so I took the opportunity to do some testing. The heavy weather jib looks good. I might have made the clew a bit too high, but no big deal.
So that's good.
The bad news is that the windvane is pretty much a fail. The good stuff...the trim tab controls the rudder with practically no effort at all on the trimtab tiller. I can steer the boat by gently tweaking the trimtab tiller with my fingertips, so the option is there to steer the boat with an autopilot moving the vane tiller. However, above about 3 knots, there's some significant shaking - vibration, probably from the trimtab operating in turbulent water off the back of the main rudder. I don't know if that vibration will get worse at higher speeds, I have to assume that it will. The vibration was noticeable at 2 knots, significant at 3 knots and destructive-over-the-long-term at 4 knots. Also, having the area of the trim tab so far back from the rotational axis of the rudder, well...it makes the rudder harder to turn by hand and it aggravates the issue of the tiller wanting to slam over instantly when I let go of it.
The killer is that the windvane itself will respond to wind direction when it's not tied into the trimtab. However, to get enough "slop" out of the sytem, I have to pull the lines fairly tight. That induces masses of friction inside the PTFE tubing, and the whole windvane system just locks up. The whole "wires inside PTFE tubing" is just a huge FAIL.
So now I have to decide if I want to re-engineer the whole thing, build an entirely new windvane and mast and hard-linked system to control the trimtab tiller....or figure that it's time to cut my losses. Even if I manage to make a hard-linked system in a couple weeks, there's still the vibration issue to consider.
It's hard to turn my back on so many months of work, so I'm doing nothing for a couple of days while I think it over. However, my gut is telling me that it's time to accept that this just isn't going to work, and get on with everything else that needs doing. I have two winches to rebuild/replace... hatch board slides to replace, a hatch to replace and so on.
So that's good.
The bad news is that the windvane is pretty much a fail. The good stuff...the trim tab controls the rudder with practically no effort at all on the trimtab tiller. I can steer the boat by gently tweaking the trimtab tiller with my fingertips, so the option is there to steer the boat with an autopilot moving the vane tiller. However, above about 3 knots, there's some significant shaking - vibration, probably from the trimtab operating in turbulent water off the back of the main rudder. I don't know if that vibration will get worse at higher speeds, I have to assume that it will. The vibration was noticeable at 2 knots, significant at 3 knots and destructive-over-the-long-term at 4 knots. Also, having the area of the trim tab so far back from the rotational axis of the rudder, well...it makes the rudder harder to turn by hand and it aggravates the issue of the tiller wanting to slam over instantly when I let go of it.
The killer is that the windvane itself will respond to wind direction when it's not tied into the trimtab. However, to get enough "slop" out of the sytem, I have to pull the lines fairly tight. That induces masses of friction inside the PTFE tubing, and the whole windvane system just locks up. The whole "wires inside PTFE tubing" is just a huge FAIL.
So now I have to decide if I want to re-engineer the whole thing, build an entirely new windvane and mast and hard-linked system to control the trimtab tiller....or figure that it's time to cut my losses. Even if I manage to make a hard-linked system in a couple weeks, there's still the vibration issue to consider.
It's hard to turn my back on so many months of work, so I'm doing nothing for a couple of days while I think it over. However, my gut is telling me that it's time to accept that this just isn't going to work, and get on with everything else that needs doing. I have two winches to rebuild/replace... hatch board slides to replace, a hatch to replace and so on.
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Intermission
Member
The Hobie 16 rudders would hum out of the box, and we would sharpen the last half inch of their trailing edges with a sureform rasp.
In the New Boat 4 Tchoup thread, sharpening one side at a 30 degree angle on one side is probably better.
You might want to take a look at both the rudder and the trim tab's trailing edges no matter what you end up doing for control?
In the New Boat 4 Tchoup thread, sharpening one side at a 30 degree angle on one side is probably better.
You might want to take a look at both the rudder and the trim tab's trailing edges no matter what you end up doing for control?
I know that the trailing edge of the main rudder is rather too thick, about 3/16ths of an inch. I don't notice anything until I get up to about 5 1/2- 6 knots, though. I may slip a thin fiberglass or plastic batten into the trailing edge and fair it in. The trailing edge of the trimtab is much finer.
What has me stumped is the apparent high success rate of incredibly crude trimtab systems, as seen on YouTube and a couple of websites that provided inspiration....and I mean CRUDE..
The thing is, I'm nearing the end of the single biggest chunk of "time off" I will have before June. I don't have time any more to make a whole new vane system....or at least I think not. I can throw $900 at Scanmar for a Pelagic autopilot, spend two weekends getting it installed, and have my ST2000 for a backup. But today is not a good day, lets see how I feel about it tomorrow and the day after tomorrow.
breezetrees
New member
Is it a hum like a hobie rudder or laser daggerboard, or is it a lower-frequency shake?
I wonder if it could be control-surface flutter like airplanes sometimes have? The fix for this is usually to move the CG of the trim tab forward, you could try adding weight to the trim tab's tiller. Lookie here
Just a wild guess that could be totally wrong. I did a lot of work on flutter in graduate school but it didn't pay the bills so have moved on.
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It's not hum. I get some relatively high frequency hum off of the trailing edge of the main rudder when the boat is really moving. This is a lower frequency shaking.
The trim tab is pretty fair and pretty smooth. It's not a pro job, but it's not bad.
I mean, compared to this: http://www.girlinagale.com/2010/11/cvane-self-made-wind-vane-steering.html
Which is flat slabs, no foil shape at all, but that steered her boat. Mine is light years ahead of that.
Or this, which is a completely slab-sided rudder, with a trimtab which is nothing but flat stock welded to rod.
In the Sayes rig, the trimtab is moved 'way aft, out of the turbulence of the rudder. in the crude versions above, as well at the Autohelm windvane, the trimtab is immediately behind the trailing edge of the rudder.
OK, so this trimtab turns the main rudder with practically zero effort. I put the tab 4-5 inches behind the main rudder for the mechanical advantage, I wanted to make sure that the trimtab had the power to turn the main rudder. However, I might try moving the axis of rotation of the trimtab to right behind the main rudder...just move it up 4 inches. That's a "job" but not a difficult one....one afternoon and done.
While I nurse my wounded ego and try to decide what to do, I attached the assy bracket to the base, today.
Because of how the bracket and pole set up on the foredeck, I have a stout bolt embedded in the wood and epoxied in there with sawdust. It's not going anywhere, though I won't be able to crank down on the nut with umpty-ump pounds of torque The bolt is essentially straight up-and down, and located at the bottom of the arc cut into the wood, where the pole bracket goes.
Because of how the bracket and pole set up on the foredeck, I have a stout bolt embedded in the wood and epoxied in there with sawdust. It's not going anywhere, though I won't be able to crank down on the nut with umpty-ump pounds of torque The bolt is essentially straight up-and down, and located at the bottom of the arc cut into the wood, where the pole bracket goes.
I opened up and greased two winches today...good stuff. However, I also discovered that ...I think.... the electrical panel is shot. The batteries are full-up. The autopilot is on it's own circuit and it gets juice. I can turn on the cabin lights, though they're dim. However, neither the running lights nor the radio/cigarette lighter/USB charging ports power up. I checked the fuses, replaced one, it didn't help. I need to test some more but I'm pretty sure that the electrical panel work just jumped to the head of the list.
Dazzler
m/v PACIFIC LOON
Sounds more like bad ground(s), especially since the lights are dim. Dim = resistance. Look for loose and/or poorly crimped connections. Tug on wires.
Unlikely that the panel is the problem, but if you decide to replace it, I can offer some lightly used fuse panels.
That's a good thought. A couple of wires wound up in the bilge, sitting in salt water during my qualifier, I should look over all those connections.
Intermission
Member
Just changing out the terminals on my battery cables from clamp on to crimped lugs, killed a half volt of loss, and
despite lock washers, the nuts on my main switch occasionally loosen up, causing all sorts of problems.
I encourage you to start from the batteries, and main switch and work your way out to those connections in the bilge.
Salt water and electricity is a marriage made in hell.
despite lock washers, the nuts on my main switch occasionally loosen up, causing all sorts of problems.
I encourage you to start from the batteries, and main switch and work your way out to those connections in the bilge.
Salt water and electricity is a marriage made in hell.