Like the swim platform, raw water intakes for the main engines, the Panda genset, and the air conditioning systems, since the trim tabs are under the waterline, I want them functional and sealed water-tight when the boat splashes.
Longtime readers will remember way back in 2013 when I made patterns for replacement trim tabs. A highly paid “professional” fabricator had previously taken mine back to his shop, then either threw them away or lost them. In 2016, I partially installed the new stainless steel trim tabs, basically just applying caulk and bolting them up to the original locations, without connecting the actuators or wiring. At the same time, I disassembled the “Roamer Cruise Control” gauge, which is basically a set of trim tab angle indicators, and found some components inside had “let the smoke out.” Fast forward to October 2022, and I thought I’d see if I could wrap these things up.
Port tab easily connected to the actuator shaft
Starboard tab’s actuator pin was welded on crooked
It’s only a few degrees off, but that matters. It’s amazing to me how consistently incompetent the marine contractors are in my area.
I put a large wrench on the tab and bent it into position
The pivot pin wouldn’t go fully through the actuator shaft, so I had to redrill the hole
I was finally able to connect the starboard tab and actuator shaft
Next, I applied bottom paint
I didn’t put bottom paint on the trim tabs because in my experience bottom paint quickly falls off of stainless.
Trim tabs are done on the outside
On the inside, the “Roamer Cruise Control’ actuators could use a cleaning
The motors, gearboxes, and jackshafts worked fine. They just needed to be cleaned and re-greased.
I’m not keen on that gap between the gearbox and mount
I added two washers to fill the gap
The gearbox screws are a very unique design
These two screws hold each gearbox in position. Unfortunately, I lost track of one of the screws for the starboard actuator. For years, I’d been looking for it on the boat and in my garage.
The screw head fits inside the hole in the mount with a couple thousandths of an inch clearance
With only one screw in place, the gearbox twists out of alignment. With a replacement screw that isn’t the exact same size and shape of the original (even if it threads into the hole in the gearbox just fine), the gearbox twists out of position, though not as badly as with only one screw.
I was at the point of taking one of the screws to a machine shop to see if they could replicate it when–lo and behold–I found the wayward screw under some plywood scraps I was saving in the aft stateroom!
It was absurd, the joy I felt at finding this little bugger
I probably should have noted which wires go where
The Roamer Cruise Control gauge at the helm gets the signal for the angle of the tabs from this gear-driven rheostat that rotates when the actuator jackshaft turns either direction. There are three wires coming off the rheostat but only two wires coming from the helm gauge for the actuator on each side.
Fortunately, a fellow Roamer 46 owner was able to snap some pictures of the connections and that got me back in business.
With the electrical connections figured out, I painted the motors
I wrapped up the actuators with new shrink connections where necessary and cable loom for the wires
Next, I moved on to the helm switches.
Swapping wires from the original switches to new ones
The original switches were mechanically fine but ugly. New Cole Hersey nickel-plated DPDT momentary-on switches look much better.
Next, I tried to tackle the Cruise Control gauge.
The Roamer Cruise Control gauge
Inside, it was mostly intact
These resistors appear to have red, white, brown, and silver bands, which makes them 290 ohms ±10%. Or that first band could be orange, which would make them 390 ohm.
Alas, this resistor vigorously ‘let the smoke out’
With so little of the resistor remaining, it’s impossible to know what ohm value it was. What’s clear is that something really bad happened inside this gauge.
The varnish also got cooked off of the super-fine coil wire here
The wire still has continuity, which is pretty amazing given what happened to the resistor. I coated the coil wire with clear enamel spray paint to restore something like the original varnish insulation.
I dug through a box of resistors and found a close replacement
This is a much larger resistor, which means it can handle more power without degrading. The bands are orange, black, brown, and gold, which makes makes it 300 ohms ±5%.
When I put 12v to the pins I (fortunately) marked B & W, then grounded the pin for the starboard angle indicator in the gauge, the needle immediately went to the pin stop in the UP position. I repeated the process for the port gauge, and the same thing happened. So the mechanisms are working. But when I took it to the boat and put jumper wires on all of the connections, the needles stayed dead regardless of whether the tabs were full up or down.
I disconnected the gauge from the boat wiring and put 12v+ to the center pin on an incandescent bulb. I then put a jumper wire from the actuator rheostat signal wire to the ground connection for the bulb. When I cycled the tabs up and down, the bulb correspondingly got brighter or dimmer. Which I think means the rheostat is sending the proper signal.
I took the gauge back home and tried some different approaches to see if I could make it work. A daisychain of resistors on the 12v supply, effectively dropping the supply to 9vdc, finally got the needle to move a bit without slamming into the UP stop pin.
Finally, subtle needle deflection
Same on the port side
I’m stumped. The tabs work fine, so they’re not holding me up from splashing or driving the boat. But it would be nice to have a working Cruise Control gauge. Off the boat, I can trick the gauge into sort of working. On the boat, the needles don’t move, though incandescent bulbs DO grow brighter and dimmer based on the tab position. It seems like the gauge should work, but it doesn’t.
If anybody knows of a Roamer on Purgatory Row of a boatyard somewhere with this Cruise Control gauge, I’d be interested in buying it. And if anybody knows the value of that resistor that got smoked, please let me know in the comments!
Next up in our 1969 Chris Craft Roamer 46 Refit: Wrapping Up the Salon Entry Door
1969chriscraftroamer46 