USS Skipjack
Introduction
February 2018. While building the USS Marlin I was introduced to David Merriman by Tom Chalfant. Tom was following my USS Marlin build on RC Groups. David mentioned runing the Marlin at the submarine fun run in Groton. So September of 2016, I met up with a bunch of these guys at the New London Naval Base in Groton Connecticut. Running models at North Lake with these guys was an awesome experience and the facilities were very nice. I only had my USS Marlin to run and at that time so I decided I would like another submarine. Everyone mentioned how easy this kit was to build and how fun it was to run. So sometime in 2017 I bought the kit and also acquired the sub driver from David. I started on the model in February 2018 then stopped in March or April. The Skipjack was put aside for a while, I moved, then started back on the model in 2020, on and off.
Table of Contents
Click on the link to take you to the section of interest.
1 Hull Warp
2 Sub Driver
3 Sub Driver, Servo Tray
4 Sub Driver, Battery compartment key-fob tray
5 Sub Driver, foundation installation
6 Torpedo Doors, Openings and Doors
7 Torpedo Doors, Hinges, attempt #1
8 Torpedo Doors, Hinges, attempt #2
9 Gluing hull sections together
10 Hull, filing and feathering beveled holes
11 Hull interior modifications
12 Lower hull exterior body work
13
14
15
16
17
18
Hull warp
February 2018. All of the parts were removed from the box and inspected. The aft upper and lower hulls were put together and there was a noticeable gap between the hull sections. Applying pressure to one of the sections by hand did not change anything. I made a jig to prevent the hull from spreading and clamped the section in place. I also carefully heated the hull with a heat gun to help eliminate the warp. As can be seen in the last picture the gap has narrowed. For this problem I will continue the update at a later date.
Sub driver
June 2020. As I’m building the Big Marie S (BMS) I decided to start again on the Skipjack. I’ll be spending more time on the BMS while still making progress on the SJ. I did not know where I had left off so I had to sort thru the box of parts and figure out where things belong. I separated the hull and the sub driver (SD) parts into their own box. I made a stand for the SD so it’s not bouncing around, and it looks more professional. The stand interlocks so I can take it apart for storage.
Sub Driver, Servo Tray
June 2020. After trying to fit the pushrods, I determined how I previously positioned the servos on the epoxy sheet was not going to work. The servos interfered with each other. So I cut another tray from the 12×12 epoxy sheet that I have. I bought a 12×12 epoxy sheet from McMaster Carr a few years ago. I have 1/16 and 1/32 inch thicknesses. The servo tray is 1/16. Holes were drilled and cut for the servos, then servo mounting holes were drilled for the 2-56 tap. Carbonate sheet can be found here at McMaster Carr. You should be able to find it elsewhere on the internet.
Sub Driver, Servo Tray
June 2020. Once the new servo tray was ready I had to make standoffs so it can be mounted to the electronics tray. I tapped styrene tubing with a 2-56 tap. Since the styrene is soft it was tricky not to crush the styrene. The two rear servos needed to be raised so the pushrods cleared the other two servos. I drilled holes close to the edge on 1/4 thick polycarbonate for the servo mounting screws. Once the holes were drilled I cut the four sections to length. Holes were then drilled in the electronics tray to accept the standoff mounts for the servo tray. The servo arm was reamed out to the size of the 1/16 brass pushrods. Then the servo tray was mounted on the electronics tray. I needed to reset the pushrod seals in the aft bulkhead so everything lined up properly. Now I have a nice neat package. Don’t have to bother with z-bends to get the pushrods to intersect with the servo arms.
Sub Driver, Battery compartment key-fob tray
January 2021. I’ll be using a remote key-fob device I bought off of Amazon to turn the electronics on and off. There is plenty of room in the forward part of the SD (Sub Driver) to mount it. I built a tray from wood that slides into the chamber. I thought of making the tray from acrylic, wood was easier to work with. I traced the inside of the forward SD bulkhead onto 1/4″ thick wood to get the proper curve for the four stubs, then cut and notched all of the pieces. The tray was made to clear the hole for connections to the electronics chamber and it can be rotated 180 degrees to give more space at the top or bottom. I put a square section at the rear that I was going to have Velcro on which would hold the tray in place. But, the Velcro adhesive would not stick to the resin bulkhead. I tried other double faced tape that was pretty sticky and that did not stick either. Will have to come back to that idea later. A slotted tray was made which holds the key-fob PCB in place. Holes were drilled in the four stubs for the key-fob antennae to limit wires laying around. The antennae wire had to be resoldered to the PCB as it was about to break off. A dab of silicone was used on top of the relay to keep the wire from moving around and flexing the wire connection at the PCB to prevent another break. Two small sections of PCB were cut and drilled, these were used as a positive and negative power bus. From the key-fob, the red and black wires are input from the battery. These were routed thru a slot to the underside of the tray to connect to the battery with a Deans connector. The output wires, red and black, were soldered to the respective power bus. The only connection to the power bus now are wires which go to a two pin bullet connector which in turn goes thru the ballast tank for power to the electronics in the aft chamber. I’ll be adding another connection later which will connect to a waterproof connection which will go thru the forward bulkhead to power LED’s. Two sections of heat shrink tubing were added on the end of the antennae wire to keep the wire from sliding thru the hole in the stub. And now that everything is mounted, tested and working fine, the tray cannot be rotated 180 degrees.
Sub Driver, foundation installation
January 2012. As per the instructions, the forward SD foundations were installed. A cutout was made in the foundations before they were glued in place. The shock absorber was held in place with double sided tape so the holes can be marked for drilling. A pin vise was used to make a slight pilot hole. After the 3/32″ holes were drilled a bevel bit was used to make a bevel on the outside of the hull. Then the shock absorber was bolted and glued into place. Locktite was used on the bolts, as per the instructions. For the SD strap mount, holes were marked and drilled. On hole came out on a vent. I’ll be moving that bolt aft a little and drilling a new hole. The simulated vent will be drilled and filed out so it looks better. The aft foundations were also glued in place against the correct rib.
Torpedo Doors, Openings and Doors
January 2021. A while ago I had already opened up the lower torpedo door openings. I was only going make these lower doors functional but in 2021 I decided to do the upper doors as well. I won’t be touching the center doors. Once an opening was drilled, files were used to get the finished shape utilizing the impressions that were already there. The inside opening was beveled outwards to give more room for the doors. At some point I noticed the positioning from the center door was not symmetrical. The measurements from the center door edge to the respective port or starboard opening was off by 1/32 to 1/16 inch. Not a problem, just moved on and used the existing hull impressions as is. Gray 1/10th styrene was then doubled up and shaped to fit into each opening. I got them as tight a fit as possible. White styrene was then used as a backing to prevent the doors from popping thru the opening. The final step was to fair the outside portion of the door to the hull. This was done with files and blocked sandpaper.
Torpedo Doors, Hinges, attempt #1
January 2021. I had a few ideas about how to hinge the doors. To begin, the locator studs at the very bow were in the way so the studs on both the upper and lower hulls were removed. I used 1/10″ Plastruct to create the hinge straps. A small section was glues on the end of a 1/2″ wide section. A hole for a 0-80 machine screw was then drilled thru this and the straps were cut so that I now had two straps. A bevel was filed on one side so the door would open horizontally. Then the foundations were filed and fit to shape. They kept getting smaller and smaller and hard to handle and they were not uniform. You can see the progress in the pictures. The foundations were tapped for the 0-80 machine screw and the strap hole was enlarge for a free fit of the bolt.
Torpedo Doors, Hinges, attempt #2
January 2021. Next I started on the upper door hinges. After learning from that, I decided to make one foundation for both doors. This worked out well so I decided to remove the lower foundation that I previously did and redo that one. In the end they both came out well and all doors open evenly.
Gluing hull sections together
January 2021. The lower hull section centers were marked on the hull using a center finding ruler. The joints were sanded and washed with water. Weldon #?? was applied to the joint to soften the polystyrene then a tube of Weldon #16 was applied and the sections were pressed together. The Weldon #16 was thick so I should have mixed the liquid Weldon in to make it more pliable.
Hull, filling and feathering beveled holes
February 2021. To eliminate the bolt holes on the hull bottom, drops of CA glue were placed in the hole and baking soda was pushed into the glue. Once dried, the filler was sanded smooth to the hull. A few applications were applied to be sure any holes were filled.
Hull interior modifications
February 2021. On the lower hull, working my way aft to forward, sections of the ribs were removed so that water would flow and drain from the hull when the model was removed from the water. In some places this cannot be done so I added a hole in the hull before a rib to let water in and out of the hull in that section. The oval nubs that would have been part of the static stand were also removed. I used a drum sander cylinder to sand some sections smooth. Similar ribs on the upper hull were also cut open so that air would not be trapped and would flow to higher points to exit the boat.
Lower hull exterior body work
February 2021. Somehow when the lower hull sections were glued together they did not meet correctly. The section that went over the other ended up being raised. I needed to smooth the transition between sections. On David Merriman’s suggestion I applied Evercoat EuroSoft to fill the gap. Then applied Epoxy with lite cloth to seal the Eurosoft. Then applied glazing putty to smooth out any residual unevenness. And due to this there was a gap in the corner where hull sections met. I applied Press n Seal on one section and filled the gap with EuroSoft and sanded smooth.
