Even though I have posted queries on my
forum, and numerous others, no real answer has come. I am talking about
the hydraulic pump drive we have installed for the auto-pilot. The
problem has been confusing to us as well as to those with expertise in
the field.
The pump itself has been working flawlessly every time we try it, and seems to have no difficulty pulling the rudder over. The problem is if it is left running to "hard over" position, that is, right to the end of the cylinder, it jams. When reversed the pump sounds like it is free wheeling but nothing moves. If the manual steering is turned just a tiny bit, the pump kicks in and away it goes. Normally this wouldn't be a problem because limits can be set inside the auto pilot, but Gena wanted to have a manual rocker switch sort of steering as well...not that I disagreed. Bleeding air, cocking valves, even pumping out the fluid didn't work. It just sticks. The only solution, I suggested, was to "put a pair of stop switches in so the main cylinder would never reach the ends." which Gena thought was crazy at first, but after being thwarted by every other attempt, she was willing to go along with it.
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The wiring of such a setup
was a little work, as nothing went aft from where the pump is. The
rectifiers ( diagram left) allow current though an open switch once
reversed. Other wise as soon as the switch was opened, nothing would work. Instead of ordering the large rivet-style rectifiers one usually uses for such things ( even though they're a pain to mount! ) I chose to go with a full wave bridge rated at 30 amps. (lower left in the top of the page photo) The lower 2 rectifiers do nothing. When turning to port, the red terminal has the positive side. Once the port limit opens, only a positive on the green terminal will allow it to close. MOT is the motor in the pump. The switches are "lever" type, SPDT, 10 amps or so. Gena mounted everything, and aligned the levers by cutting slots in the mounting plate for each switch. |
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We tested it several times without a single jam, but the real test will be once we're out there in the big blue. It'll be mentioned somewhere in the "what worked what didn't" page once the building site is complete! | |
Speaking of which,
there isn't a lot left to do as the 10 year weekend project winds down! We
look around and, as mentioned before, sometimes don't notice really obvious
things that need to be done. Here's another, which took most of my day. I had purchased these oak boards to lay into the pulpit ( bow sprit ) as a floor. I made the steel frames long ago, but never got around to doing the wood part. I had coated them once last night with oil then varathane, and now they are carefully cut to shape, have re-oiled and varathaned them. |
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They have been glued
on lightly to keep the alignment for drilling little nuts and screws. The aft-most floor flips up to the port side on hand-made hinges (Day 401) so I brought out the pro-furl drum section to test for clearance and everything looks good. I was waiting for the 'thane to dry when it dawned on me that I hadn't made the motor mount yet! The cute little dingy motor needs somewhere to sit when not stowed below, or on the dingy. |
I hadn't really given it
much thought but knew where it should go. Somewhere aft, on the corner or
the handrail. Great! More welding! I took some flatbar and cut the shapes to make the plywood board mount. |
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Then added on a short length of 1/2" tubing left from the hydraulic system by flattening out the one end to weld, and drilling the other for a small U-bolt. Easy! The photo (left) shows it in place, thanks to amazing time-lapse photography, without the motor on. I'm sure it'll work right? | |
It's getting pretty
crowded in the push pit, but what can a girl do? As long as it's tidy is all
that matters. The next thing, which turned out to be complicated because I want it to last 100 years, is the cockpit dining table. I had added a couple of hooks on for it when I made the pedistal, but gave it no further thought until recently. Pictured to the right is one of "those: oak TV trays ( everyone seemed to have them already when we tried to sell the rest at the garage sale!) which are pretty nice looking. I re-arranged and cut the legs, then made a hook for the eye on the pedestal, and drilled large holes into the ends of the outer 2 so they could slip over the hooks on the pedestal. It works, but one good banging into, and it'd break off for sure. They must be reinforced with stainless. That's for tomorrow. ( More welding again! ) You may have noticed the snow in the picture even though it's almost May. Oh well, at least we don't have to cut the lawn yet ( which takes valuable time away from working on the boat! )
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Day 455:
10 hours - (on and off) Chop-Shopped TV tray, made motor mount, cut and
"mounted" bowsprit floor, put together and wired in hydraulic switch-out
assembly