Trumpeter Seawolf Start

[bigdave]

Hi Dan,
You may have

Hi Dan,
You may have water in your pump from when you sank. George had that problem in his system I think he had to take the pump apart and dry out the rubber valves. Dr Art uses rubber bands all the time on his bladders. I never have. Works OK for me. You are right about constricting the schrader valve. That’s why I use the Clippard valves. They are slow, but some guys do not like the slow reaction. They like it to come up fast. Not me!! I was wondering how you were doing. BD
.

[danl]

Dave,
Thanks for the quick reply.

Dave,
Thanks for the quick reply. I'll check out the pump tonight, although (thanks to your brilliant isolation of the rear chamber) water never got to the front two chambers, but there was condensation in them.
You use clippard valves to dump air from the bag back to the tube, making the sub dive, right? And you activate the pump to inflate the bag to surface. How do you control the rate of inflation? With the pump I have, just a short as possible flick of the control for a quick burst from the pump was enough to rocket the boat to the surface before I added the plug with the small hole. Even with the #80 hole, all I ever use is a quick as possible pulse of air to start rising. Is there something I'm missing here?
(I should add that I had only one real pond run after the sinking. Everything worked great, except constant depth was hard to maintain. The stuff I'm describing now is all in 11" of water in a bathtub. I can maintain midwater fairly well with no forward movement. Probably would result in very good pond running with the forward motion added, but I'm trying to get the bag to act like a piston Geez, wish the water wasn't so hard up here right now...)
I'll post pics tonight of the finished boat and the latest in making the bag behave - rubber bands over a pressure plate that covers the bag.
This is a cool hobby - always a challenge.
BTW, could I buy a new bag from you? I "cut and pasted" the original and have made various shapes of bags with sheet latex and neoprene cement. Would like to try the band and pressure plate with an original bag.
Let me know how much.
Thanks.

[danl]

Here is a pic of

Here is a pic of the boat and of the plate rubber-banded over the bag to maintain even expansion/compression. You can fine tune front to back bouyancy be number of bands and their location. Even with all those bands, the pump will fill the bag.
The plate is thin styrene, curved and with scalloped edges to hold the bands in place, and holes to prevent air trapping under the plate.
Still need to get the total air flow rate down. The #80 hole orifice still lets the air rip through.
Works great in the bathtub. Waiting for spring....

[bigdave]

Nice hull detail! She looks

Nice hull detail! She looks great!!
Cool idea on the pressure plate and the rubber bands.
That is what I like about this hobby. Always something new to keep the mind working.
I have not really seen a problem with the pump filling to fast. I think you are confusing a static trim to a dive or underway trim. Unless (like you said) you have a piston tank where you can make very small adjustments it will be hard not to see a big trim change when the pump is inflating the bladder.
Once the sub is underway that is what your dive planes are for. Everyone has a different way they like to trim there boats. I like to trim mine so the boat is at neutral bouncy (as close as possible) with the bladder empty. Then easily drive the sub under with the planes. Give her a little shot of air while moving and she will come up nice and slow. You will find that if you stop at any depth the sub will pretty much stay at that depth. The RCABS is about as close to a piston as you can get. But it is not a piston. BD.

[danl]

Dave,
The air pump was allowing

Dave,
The air pump was allowing leakback. It wasn't water inside, but fine white powder fouling it up. I used talcum powder to "finish" the experimental bags I made. Even though i removed all the excess talc, small amounts got back to the pump. Cleaned her out and all is well.
Yep, your right - I'm thinking that static bouyancy has to be great to get good underway trim. I just have too little running time and focusing too much on bathtub performance. From what you're saying, this boat should have great underway bouyancy control cuz it's very god in the tub with the modifications.
Thanks for the tips.

[Guest]

Instead of curved styrene for

Instead of curved styrene for the pressure plate, I always used a 2 liter soda bottle, and cut it to fit over the bladder and under the rubber bands. I like to use inexpensive available materials whenever possible. The number of rubber bands, and their positioning, can be adjusted to insure even inflation of the bladder.

[danl]

Art,
Took me a while to

Art,
Took me a while to figure out the band/plate thing, and it's ancient history to you.
Where can I find more of your expertise? Do you have any other suggestions for my Big Dave WTC/Seawolf?
Thanks much,
Dan

[bigdave]

I am glad you tracked

I am glad you tracked down the problem. You guys up there in your area should look for an indoor run site for the winter. We had great luck with one of our local YMCA's. One of our 8-balls was a member of the Y and worked out the deal. We are basiclly paying for the lifeguard to be on duty. We get two hours once a month on a sunday night. We all look foreword to that Sunday night. (Thanks Mr P!! )

[anonymous]

Dan,

you did an outstanding job

Dan,

you did an outstanding job there! congrats!

steve

[tmsmalley]

Hi Dan - I hope

Hi Dan - I hope you are planning to bring Seawolf to the EMYC Waconia Pool run in a couple of weeks!
See you there?
Tim

[danl]

Yep - will bring the

Yep - will bring the sub to the pool. Really anxious to see it operate in the open water.
The second (and last) run at the pond, things went very well. (That was after the post sinking rebuild), but depth control and porpoising were a pain. With the recent air feed and bag mods, I'm thinking the is boat should run very very well.
Hey - what happened to Atomic subs? I planned to buy one of their bigger boats - probably the Seawolf, but I read that they are no longer in business.