Liberty Ship William Dawes

smoke testing is fun. i'm fairly good at getting the smallest piece of solder across multiple terminals frying whole boards.....

if i had seen that it was lead acid and not LiPo i wouldn't have said anything. good thing tugboat has better eyes and actually uses them.

 

I had a Nuclear-trained submarine machinist mate 1st class (aka MM1(SS)) explain to me one time his version of electrical theory: Electrical equipment is filled with magical grey smoke. So long as it's full of the smoke, everything is fine. If it starts leaking out, call an Electrician (me), 'cause it's broke. Scary part is, I think he was serious.

And Keith, like Tuggy, I've seen way bigger smoke tests done. Like a reactor plant main feed pump shorted out. No worries on an ESC

 

Lead-acid for the Liberty ship. I’m just trying to stay in character. Cheap and behind the technology curve.
Keith

 

Time for an update on the William Dawes.

I have installed the rudder servo. I ended up using a gear system on a pushrod instead of a simple pushrod as originally intended. There was not enough space between the pushrod and the rear bulkhead to allow a pushrod.




Notice how close the prop is to the rudder, and how close the gear is to the rear (solid) rib.


I used Servo Plate A attached to 90 deg short channel bracket from Servocity https://www.servocity.com/
Yes it would be possible to drill and tap aluminum, but I don’t have the correct tools. This gives a waterproof threaded servo attach point.

I have all of the components installed. The ESC is filled with epoxy, then has 2 coats of Scotchkote on the outside. The receiver and pump switch each have multiple coats of Scotchkote.






Next step is installing the interior armor.

Keith

 

Time for interior armor.

I could have used Bath Tub Liner. Great stuff, but this is a liberty ship.


I will be using Pop Bottle Armor. Each Pop bottle can give 5” usable armor.

Cut it in half and you get two pieces 2.5” high. It will take 3 Pop bottles to armor the William Dawes.


To attach the armor I have stolen another idea off this site. This time it is sansei Lou. When I saw the inserts on the Frankenship build, I ordered some the next day.

In this case I did not want to add stringers, so I cut a ½” strip of ¼” fiberglass aprox 10” long. Then drilled the strip and set the inserts. Then I cut the strip into ½” pieces and sanded an angle onto the outside. Hopefully this will prevent BB’s from breaking them off.


Install the PBO with washers.

 

Time to skin the William Dawes.

I am out of silkspan and dope, so for the William Dawes I will be testing KimTech tissue. My first attempt was to use 3M 77 spray adhesive. I was not happy with the adhesion. I had used it in the past, but this time it was peeling up on the edges and was easy to pull apart. NOT ACCEPTABLE. The purpose of the interior tissue is to try to contain splintering and cracking.

I bought some lacquer, and am very pleased with the results.

After applying the KimTech to one side of the balsa, I lay out and mark the balsa for contact cement.



Contact cement is applied to both surfaces with a high tech brush. I used the same bush for all applications to save money… let sit for 10-20 minutes, then carefully line up and press together. Continue to next section and repeat.


At this point I do not expect to have a watertight finish. There may be some gaps.



I use 150 grit sand paper to bevel the edges of the balsa.



Next I apply the outer layer of tissue. Make sure that there is overlap past the balsa. This will be the waterproof layer.

 

Nice on the hold-downs. For a convoy ship you should be ok, but don't just glue them for a warship. They will get shot off and then bb's can get in and bad things will happen (like tugboat in a speedo, not sure how that applies but it is a bad...)
On a ship I would notch the sub-deck so that the fiberglass pieces fit inside the wood subdeck. This gives more surface area to use for gluing. In your liberty ship, you can also run a wood rail the length of the ship that goes on the face of the sub-deck creating a 90 degree angle. Use epoxy to fill behind the rail and you get a strong joint. Then fasten the inserts to it (the wood rail can be 1-2 inches deep). Make sense?

 

Sounds like a better solution. I will keep that in mind for if/when they get shot off.

For the warship, I plan to make some ribs for where I want incests. Similar to what you have, just not every rib. I know I should notch the sub deck. I haven't decided if I will yet.

 

Dang spell checker.

 

Hey, what is the model number of that Turnigy switch for the pump? I can't quite make it out.

Thanks!

 

Thanks!

 

, wow, really , glad i'm nosy , that will come in use , thanks guys

 

so you used just regular wood lacquer on the kimtech wipes to bond them to the balsa?
i read sheeting threads but much seems to be said in person leaving out little things.

 

Did a float test the other day. One thing that I had never noticed was how unbalanced a 7AH sealed lead battery is. I just barely fits inside the width of the boat. Makes it list A LOT. Change of plan. I had some 4.5 AH batteries, so I tacked some wood in the bottom to center them. Works like a charm. Now I just need to wait until I can use up a batch of mixed epoxy & I will finish her off. I have also done a little clean up with the wires.