1/96 Thor Permit

[Parallax]

Hi All,
My dad and I have started putting together a 1/96 Permit and I'd like to share our progress as well as get advice on how to finish it. William (SSBN659 on this forum) provided us with a beautiful USS Permit kit from Matt Thors. My dad served on the USS Flying Fish, and I plan on getting a Sturgeon when it becomes available from Precision Pattern, but we are both really happy with the Permit.
I got a 3" subdriver unit from Bob Martin along with all the running gear, and we have finished assembling all of the electronics and are moving on to the snorkel system.
A few of the issues I am trying to figure out right now:
1. How to fit a snorkel inside of the small Permit sail. I have been scratching my head trying to figure out how to fit the snorkel and am considering rigging up an alternate snorkel that would replace one of the periscopes. If anyone has ever done such a thing or has an idea please let me know.
2. Does the prop shaft need a bearing or washer between the kit body and the prop.
3. How to attach the magnetic linkages to the existing sub hardware. The existing linkages are too large to fit the magnets.
4. Our WTC is smaller then the original. I am debating if it makes more sense to move it towards the stern, or leave it towards the bow with the location pin, and just get a longer shaft for the prop.
5. The mounting broke off from the bow, and need to find out what kind of epoxy is recommended to re secure it.

I'd like to thank Matt Thors, Bob Martin, and William (SSBN659) for helping us get to where we are now, and I am looking forward to completing this project.
Thank you!
Mike

[salmon]

1. You can run a tube up the sail and the float can be made to float in the sail, but if the sub gets enough freeboard it can be mounted under the deck.

2. Yes, a bearing should be installed and a washer placed between prop and bearing. You should also have a washer between the bearing and dog bone connector inside the hull too.

3. you have a couple (at least) ways to mount the magnets. Drill the end of the connector to match your pushrod. You could get a brass tube to go over the end of your pushrod (a sleeve) then use tube or rod to get down to 1/16". If you have threading at the end, it can then be used to make adjustments.

4. The locating pin can be moved. The ballast tank should be your concern. I want to say center, to slightly forward, but someone else could speak to that maybe better than I, but it looks O.K. from my guesstimation. Nice sub too. You both have done a great job getting it to look so good.

5. Marine epoxy or a longer curing epoxy (24 hour cure) do not use the 15 minute or shorter cures.

Hope this helps!
Peace,
Tom

[Parallax]

Tom thank you for the information! I wish we could take credit for how nice the hull looks, but we bought it already done from SSBN659 who did a wonderful job with it. I like the idea of tapping the rods for threading, I think I will go that route. I'll do some measurements to see exactly where the ballast tank is sitting in relation to the hull. Do the washers need to be brass or can they be steel or copper?

[subdude]

Mike,

Tom has pretty much nailed it for your questions. Just a couple things I'd like to add to help clarify.

2. If this boat has been built to run already, there is almost certainly a cylindrical bearing installed in the stern cone of the hull. What Tom is saying is that you should have a thrust washer on the shaft both between the rear of the hull and prop, and in front of the prop shaft bearing support crossmember (seen beside your thumb in photo 201851) and the yoke for the dogbone connecting the WTC to the prop shaft. Those thrust washers can be brass or plastic. Never, ever steel. Nothing that rusts. And don't forget that you want to use stainless steel setscrews to secure things on the prop shaft.

4. The ballast tank should indeed be roughly just forward of center of the boat (centered under the aft edge of the sail always gets me close). You will final trim with foam and lead to get it spot on.

5. Use epoxy with no less than one hour cure time. Anything else will eventually soften from water exposure.

Welcome aboard!

Jim

[Parallax]

Hi Jim, thank you for the warning about the washers, I just picked up nylon ones. I have to hunt down stainless steel set screws. Is there a preferred brand/type of slow drying Marine epoxy that is recommended by users on this forum.

Snorkel Issues:
There is not enough room to fit the horizontal style snorkel between the WTC and the hull, and the sail is so small I don't think i can fit the normal style vertical snorkel in. After thinking about the problem for a while, I am trying to work out a costume snorkel setup that would replace a periscope. I would try and make it look as much like a scope as possible, but the main thing is to make it functional. I am attaching two pictures I drew up of what I am thinking, please keep in mind its not to scale.
I am modifying ideas I have seen of existing snorkels on this website. The main idea being I would run 2 vertical brass pipes through the sail. A foam block shaped like a periscope mast would be free floating on the forward tube, but attached to the rear tube which runs air. The forward tube is basically fixed in place so that the head on the top of tube cannot move. The rear tube would move up and down with the float, so when up it would be forced into the stopper. Does this sound / look like a promising direction?

[salmon]

If I may offer a thought, before making a custom snorkel, contact Bob the Builder. He is on this site and get him involved with ideas or you Sub-Driver. Since I do not have your sub or know the dimensions of the sail, I hesitate to make a suggestion. I have worked with two different type of snorkels (one uses a float on a lever and the other you have shown here). You can reduce the height of the snorkel. Doing that may require some other adjustments, so ask Bob first.

[Guest]

Wouldn't advise the use of nylon anywhere where water is present and clearances are important- it's highly absorbent and swells.

PTFE, acetal or a blend of the two are better choices.

[Ralph --- SSBN 598]

It does not say where you are located.

You can get very small stainless washers at most large hardware stores.
You will find a section in the store where they have a bunch of specialty items in the bolts, nuts and screw area.
There should be a wall of sliding drawers with these items in them.

I get these type of washers from Lowes hardware.

[scott t]

The way you have designed it in the drawing you are trying to lift a tube, L-fitting, and the attached horizontal hose.
Maybe design it with the tube curved down and float pushes up against opening. See pipes on sub picture.

[Parallax]

I spoke to Bob about the snorkel but it is not looking good for a ready made one fitting the very tight sail of a Permit. The internal space on the sail is slightly less then a half inch wide.

Thank you for the information about nylon swelling. I went to Lowes today and picked up brass washers (Should have done that in the first place).

The u shaped snorkel is brilliant and lot less parts moving. Clearly simple is better! So here is idea #2 I might actually be able to fit this inside of the sail completely


Do either of these products look good for the epoxy?

https://www.westmarine.com/buy/west-system--g-flex-650-8-liquid-epoxy-resin-and-hardener--9223132?recordNum=13

https://www.westmarine.com/buy/west-system--six10-thickened-epoxy-adhesive--10287571?recordNum=3

[Guest]

Re epoxy, that is industrial sizes, complete overkill.

Any decent brand name epoxy with a slow cure time will do.

Good brand names- Araldite, JB weld, Devcon.

You could also use modified acrylics like Devcon Plastic Welder. These are as strong if not stronger than epoxy, but cure much faster. They toot a bit mind you.

[Parallax]

I made a lot of progress on the sub... and then had a reenactment of the USS Guitarro being fitted out at Mare Island.

I braised 1/16 brass rods onto the existing controls for the rudder and dive planes. (I know its not pretty, still learning how to solder properly) I was then able to attach the magnets to link them together with the servos inside of the WTC. One problem I am running into is the rear plane linkages seem to be catching the edge of the rudder linkage at the very back of the hull. It is really tight in there and I am not sure how to address that issue. The 1/16 rod also seems to bend a good bit because of how they are mounted to the servos but they do work.
I was also able to adjust the pin location and the WTC is now set in place, as well as hooking up the prop shaft with brass washers.


So onto the major disaster, which I am 100 percent certain was caused by human error I placed the WTC in the tub to ensure there were no leaks. Everything seemed solid so I went ahead and mounted the WTC inside the sub so I could start working on the trim. I have not gotten the Snorkel figured out yet so I decided to leave the sail off for now with the intake hose running out of the sail holes.


Everything seemed to be working when I heard what sounded like the pump running, and the the sub began to sink. After a few moments I decided to pull it out and discovered the entire equipment tray section was filled and half the battery section. After the draining and drying the tube I did an equipment check.
Batteries and remote power working. Pitch Control, Battery link monitor, and ESC are all working. However the receiver appears to have died. I jsut ordered a new one, sigh.

I have to do another round of tests but I believe the most likely cause is that I routed the snorkel tubes backwards, forcing water into the sub rather then air. I also noticed that the two servo holes that I did not use appear to have light going through them so I will run dummy 1/16 bar through them but I think its unlikely the cause. I also need to find out what kind of silicon is recommended to use on all the seals.

Once I have the new receiver I will slow down and do proper testing so i don't have another big mishap like this.

[Parallax]

Good news! Bob Martin provided me with some good advice, and all of the electronics are back up and running. I cannot begin to describe how lucky I feel right now. So after a lot more caution, drying, and cleaning I did more testing and now the ballast system is working as it should, and everything is dry.

Things to address now:
I am going to need to figure out what to do about the rear planes as there is a lot of binding when I try to make it angle up. It looks like the way the control tab is attached to the planes, it just runs out of space. I do not see a way to get at it to make alterations with out cutting open the aft section.

There is too much range of motion for both the rudder and plane. I am not sure if the solution is to use a different hole on the servo arms, or if there is a way to limit the travel on the servo itself.

Tomorrow I will apply epoxy to the bow mounting pedestal so I can secure the bottom and top together.

Once the epoxy is dry I need to adjust the trim. I think William had it trimmed pretty well with weight but the WTC I am using is a bit shorter then the original. I think if I add a bit of weight in the bow it will be taken care of.

Still working on a new snorkel but I feel like I am pretty close now to a functional design that will fit and not look too out of place.

I need to re calibrate the Pitch Controller. I had used a level when I calibrated it, but its off. I think the way the gear tray sits outside of the WTC is different then inside. I wish there was a way to externally calibrate.

Have to add the emergency blow system and then calibrate the BML to operate both the emergency blow.

[subdude]

Mike,

re: range of motion. Don't know what you're using, but most decent transmitters have a way in the programming to limit the end travel of the servo. As an example, on my Lafayette I have the rudder throw limited to 60%.

pitch controller: I know this sounds crazy, but you can always drill a small hole in the WTC to access the setup button / pot. Then tap the hole and run a plastic screw in it with a dab of silicone. I've been running boats like that for a long, long time with no issues. Skip Asay (who I learned that and many other things from) used to just seal the hole with silicone, and in a pinch just put scotch tape over the hole.

Jim

[Parallax]

I will check the radio transmitter tonight, I had no idea that might be built in. Wow that is a great idea bout the screw I will try that as well. Jim thank you so much!