Cigarette/AMG Offshore Powerboat - Page 3 - RC Groups
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Aug 20, 2017, 02:26 PM
Grumpa Tom
Kmot's Avatar

Steering Servo Mount

I had to come up with a mount for the steering servo. It needed to be stout. Shoving those two stern drives requires some grunt.

A tip I read online years ago, was to use cereal box cardboard for template material. I did, It is good and strong, yet thin. I made a template for the curve inside the hull where I planned to install the steering servo.

I built the mount out of 5 lamination, 1/4" thick plywood. I gusseted it with three gussets. It is plenty strong.

I used a CNC aluminum clamping mount to hold the servo.
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Aug 20, 2017, 02:45 PM
Grumpa Tom
Kmot's Avatar

Sealing the driveshafts

Since I had to enlarge the opening in both the frame for the stern drive and and the transom, I needed a new way to seal it off against water ingress. I used a multi-bit and cut two sizes into the transom. One size for the driveshaft and coupler and the next size up for a seal. I purchased a special foam called "Ionomer"

Ultra-Strength Wear- and Weather-Resistant Ionomer Foam Sheets
Exceptionally strong, these lightweight ionomer foam sheets offer excellent resistance to impact, UV light, and water. They stand up to wear caused by rubbing and scraping and are often used as bumpers and buoys. This foam has closed-cell construction, which restricts water, air, and gases from being absorbed.

This is what I used to make the new seals. I used a gasket punch tool and cut out the circles, and then used black silicone adhesive to secure them in the opening of the transom. Using an Xacto knife I cut a cross slit in them and was able to push the driveshaft/dog through when assembling the motor to the out drive.

BTW, have I mentioned what a CF assembling these things is! It's actually quite a process.

Anyway, the steering rods also have a flexible rubber seal and they seemed to be in OK condition. I did treat them with 303 Aerospace Treatment to soften and protect them.
Aug 20, 2017, 02:54 PM
Grumpa Tom
Kmot's Avatar

Installing the ESC's and water lines

So it was time to do the water lines, and I had to put the ESC's in their places. I connected the wires to the motors also and tidied them up with zip ties.
Aug 20, 2017, 04:28 PM
Registered User
Gravman's Avatar
Very nifty install. Got a lot of stuff going on in a small area. Can you tell me about the water cooling line you used and what appears to be a couple of small hose clamps where the two tubes join into a single line?
Aug 20, 2017, 06:09 PM
Grumpa Tom
Kmot's Avatar
The red silicone tubing i got from McMaster-Carr. There are no hose clamps. That is a plastic y-fitting that connects tubing.
Last edited by Kmot; Aug 20, 2017 at 06:17 PM.
Aug 20, 2017, 06:16 PM
Grumpa Tom
Kmot's Avatar
Just ran into a snag.

I finished the radio and electronics installations. I was running the motors and turning the drives left and right. Had to reverse the steering. While full right the starboard drive suddenly made a loud noise and it stopped spinning!

I think the drive pin in the ball of the driveshaft may have slipped out partially.

Man I hate to have to take it apart already. Boo hoo.
Aug 20, 2017, 10:02 PM
Grumpa Tom
Kmot's Avatar
It was not what I thought it was. Not the drive pin. Turned out to be the motor was locking up due to some sort of debris in it, at least that is what I think it was. Not sure what it was. Maybe a piece of solder left over from assembly, or a piece of balancing clay. Who knows. I got the motor freed up then ran it at high rpm with a vacuum nozzle over the openings in the motor. Seems to be okay now. Whew!

Back to regularly scheduled build thread.

20170820 172931 (0 min 14 sec)
Last edited by Kmot; Aug 20, 2017 at 10:18 PM.
Aug 20, 2017, 10:36 PM
Grumpa Tom
Kmot's Avatar

Steering Linkage

I thought a lot about how I was going to make up the steering linkage. Typically I use Dubro plastic links and threaded rods when I build airplane linkages. But I discovered the nice anodized aluminum Heim joint rod ends that I used to replace the ugly fake tilt cylinders on the stern drives, and so I ordered some more to make the steering linkage.

Being that it is deep inside the hull and under the rear deck, it is awkward to get to. I needed extra long screws to not only reach into the steering rods in the stern drives, but also to accommodate the Heim joints. And using the aluminum turnbuckle rods made it easy to adjust the length to match up to the two steering rods.

The nice aluminum 1" servo arm I had turned out to be 1/4" too short. As it was, the linkage would hit the servo mount when trying to go to full travel. I found a 1.25" long aluminum arm on eBay and it worked out perfectly.

The servo is a digital, metal gear, with 20Kg of torque. It has plenty of grunt and it is pretty fast too. I'm happy with it.
Aug 20, 2017, 10:48 PM
Grumpa Tom
Kmot's Avatar

Antenna Mount

I needed a way to keep the antenna vertical. There are lots of nice looking anodized antenna mounts on the market. But I just happened to have a vintage Dubro antenna mount on hand so I used it. I drilled it out to accommodate the plastic tube. I cut a slot in the side to feed the antenna through. I drilled a hole in the carbon fiber tray and installed the antenna mount. Worked out nicely.
Aug 20, 2017, 10:51 PM
Taking care of the pond.
Looking good!
Aug 20, 2017, 10:59 PM
Grumpa Tom
Kmot's Avatar

Radio Installation

So finally it was time today to get all the radio gear and electronics installed.

I am using a Flysky FS-iT4S 4-channel radio. It has telemetry feedback. I connected sensors for battery voltage and temperature. The voltage sensor will connect to the main LiPo battery and the temperature sensor is on one of the motors. I am using a UBEC and separate LiPo to power the receiver and steering servo.

Aug 20, 2017, 11:00 PM
Grumpa Tom
Kmot's Avatar
Thanks Don!
Aug 20, 2017, 11:54 PM
boat butcher
the goon's Avatar
Wow, really looks fantastic .

Aug 21, 2017, 01:24 AM
Grumpa Tom
Kmot's Avatar
Thank you, Mark!

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