Dumas Shelley Foss 36" tug build

Started by Frank v B, December 13, 2023, 09:52:33 PM

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Frank v B

#15
Bow thruster- back to the drawing board.  Arghh!

here is the set-up for the bow thruster. 
This board stands up in the bow.  The servo links to both mouse trap pinch-off loops to select left or right. A bit like the control line combat fuel cut-offs.

Tested the pump.  Two problems:
i) it seems to be weak on 4.8 volts unless on 6 volts. It clearly says "5 volts" on the label.  I can always hide behind the fact a man never reads instructions and use 6 volts.  If it burns out I will have to go back to the drawing board.
ii) It appears it is not self-priming- that makes it tough because the water has to be brought up 4" before it hits the pump*.  May have to talk to Temac's pump expert- Pool Paul.  Will try to source a windshield washer pump but it will need a separate 12 volt battery source.  Not a problem but the boat is powered by a 6 volt lead acid battery.

Back to the drawing board.

Frank


* am trying to keep all joints above the waterline so if it fails it will not sink the boat.
"Never trade luck for skill"

Frank v B

#16
Final prep before painting:
- glued in the rudder post.  The tube sits about 3/16" proud of the hull surface (photo 50, right side of photo) so the rudder does not touch the hull.
- shorthened the prop shaft housing once the rudder was in place so I could accurately place the prop in front of the rudder.
- added the prop shaft strut at the bottom of the hull.  Hard balsa, shaped it and epoxied it in place (photo 50).  Wrapped two threads of Kevlar* over it and onto the hull to strengthen it (Photo 51).  Added waxed paper and squeezed everything smooth (photo 52).
- added masking tape on the deck to start getting it ready for spray paint.  The hull will be black, the deck is grey.

Frank

* Kevlar is the gold coloured thread.  I use it because I have it.  You can use unwaxed dental floss.  It is amazingly strong in this application.

"Never trade luck for skill"

Frank v B

#17
Building is pretty well done.
- sanded the hull's fibreglass covering smooth.  Wow! Never for a minute thought it would be this easy or this smooth.
- installed the motor, prop shaft and prop in place so everything fits.  The prop does not hit the hull!
- installed the rudder servo and rudder.  It fits.
- added the battery tray and fit the speed control (an RC car one with reverse).

Added the masking tape on the deck- ready for spray painting the hull. 
Only problem- cannot spray inside the house.  I do it on the driveway but not while ice cubes litter it. ;)

Frank

"Never trade luck for skill"

Frank v B

#18
Last day of the Shelley Foss build until painting it
- installed the ESC on the side of the hull.  Two reasons: i) water always collects in the bilge (bottom), ii) this boat requires lead to bring it to the waterline.  It is best in the middle (balance) and as low down as possible to reduce rolling in waves.
- installed the on/off switches for the radio and bow thruster.  Purpose- so the boat can be assembled in the car and powered up when in the water.  This boat will probably weigh in the neighbourhood of 15 plus pounds.  My back!!
- wanted the access to the switches through the deck.  Cut a hole below the deck winch, installed the switches and built a raised coaming around the hole.  It is a lip to stop water running over the deck and into the hole.

Frank

 
"Never trade luck for skill"

piker

Hey Frank!

I DO still have the beautiful tug you sold me (Did I even pay you for it?).  I will get it dusted off and out to Toogood next summer!

Robert 

Frank v B

Robert,

Yes you paid for it.  It was $100.00.
I had to buy this replacement kit for $80.00, plus build it, plus power it.
You got such a deal*.

I remember you saying during the hand-over "I always wanted a tug".

Frank

* it was given to me (built, no shaft, no rudder, no motor, no servo) so the $100 covered the money I put into it. 
"Never trade luck for skill"

Andy Hoffer

Hey @Frank v B ,

What's the latest on your windshield washer pump bow thruster?

Is it the same design as your pool pump plumbing loss of containment?!!!

Andy

Frank v B

#22
How to paint a proper waterline: A hull has compound curves so nothing is straight in order to paint a waterline.  On this project the top of the hull will be black.  Below the waterline will be red....because it has to be.

To paint the waterline:
step 1: transcribe the waterline from the plans to the bow and the very stern.  It is measured up or down from a fixed point.  The waterline at the stern was measured from the bottom of the hull which was a corner so very reliable.  The bow was measured from the chine.
step 2: set the hull on a flat surface and position it so the bow and stern marks are an equal distance from the top of the table. Now the fire and aft marks are set.
step 3: set the hull level (left to right) until the left and right sides are exactly the same distance from the table top.  Note: I could not use a spirit level to measure "level" because the railings are not an equal height above the deck (not my fault. Ask the original builder).
step 4: clamp an ink marker in a holder and run it from bow to stern and around the other side.  It worked surprisingly well.  I used a solder clamp stand to hold the pen in the correct position.

A lot easier than I thought.

Now mask this line to paint the hull.

photo 1- (89) the hull sitting flat and level on a smooth table top.
photo 2- (87) marking pen in the holding clamp (solder clamps).  At the bow mark.
photo 3- (88) line at the stern.

Frank
"Never trade luck for skill"

Frank v B

#23
The hull masked off and finished with two coats of red below the waterline. 
It was sprayed with a rattle can of red rust paint.
Spray painting done outside...otherwise that is where I would be living if I painted the hull inside the house.

Frank
"Never trade luck for skill"

GuyOReilly