Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Submarines => Topic started by: rnli12 on August 03, 2015, 06:56:12 am
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Hi,
I have aquired a T Class submarine based on HMS Turbulent (Nuclear class) the internal cylinder layout comprises of 3 sections, it all looks very aged to say the least, are there some good diagrams out there with a simplified version based on current convention? Will post some pics later.
Front is the water pump and solenoid assembly, Middle water chamber, Rear is the motor and speed controller etc.
Regards,
Rich
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Hey, do you have any pictures? Sounds like a sheerline to me. Is the cylinder a black tube?
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Hi,
Yes it is a sheerline, but I think the internal gear could do with an update.
Regards,
Rich
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Hi Rich,
This link may give you some ideas (refurbishment of a Darnell Type XX1). I did try to use some of the original gear but (certainly the Darnell as opposed the Sheerline perhaps??) is very outdated.
http://www.theassociationofmodelsubmariners.com/t1092-darnell-type-xx1-graham-s-dad-s-boat-for-refurbishment
Photos would help.
David
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Here are a few.
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Does it all work? If it's a sheerline (rather than Eden) then it can only be a certain age. To be honest the dive and propulsion system is very very reliable and if it's all working I wouldn't change it unless you really want to (in which case I would sell the unit as a working whole and use the money to buy a new one).
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With regards to dive systems, there's been no real innovations for decades- there is only so many ways of moving water from one place to another.
As such the Eden/Sheerline system is as easy as it gets. The pumps can fails after extended use, also the cylinder seals sometimes need replacement. For some reason the latter have always been their own bespoke design instead of readily available o-rings like everyone else uses.
Apart from that however they're tough reliable boats.
Chris did make some improvements to the Trafalgar design, to help with stability and handling.
The upper hull was thinned out, and braces put in to compensate for loss of rigidity, this reduced upper weight. The other big alteration was replacing the big lead acid battery up the front of the boat with a NimH pack slung underneath the cylinder. This improved weight distribution and further improved stability.
Your boat looks like someone may have been tinkering, what's that spout mounted on top of the tank? Has someone turned the boat into a vented tank system?
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Hi,
Thanks for you response, yes it is a venting system there lies the problem I think, when flooding the tank all is pretty good in submerge mode but to surface nothing happens no good pump suction from the tank and no discharge at all until i take it out the water and physical break the seal. The solenoid change over seems slick so I dont know whether the venting system is blocked?
Any help appreciated
Rich
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I see. It's supposed to be a sealed tank. The pump pressurizes the air inside the tank to about 40 psi, enough to fill the tank about two thirds full. A servo controlled pinch valve checks the flow of the water, this is released to surface the boat, with the compressed air forcing the water out.
Not sure why someone has modified it to a vented system, but with those, you need a snorkel to be above the surface to empty the tank, so basically you can't blow ballast whilst fully submerged.
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Thanks for the info, I am wondering whether its a relief valve as I have checked for air/venting and nothing there.
The whole system works well for flood up but blowing just nothing!
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Having now had a look at the photos, I think you should keep everything but put it back to the original Sheerline system , which works very well for a lot of people.
Mr Sheerline was at Norwich and can supply spares etc.
David
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Thanks for the info, I am wondering whether its a relief valve as I have checked for air/venting and nothing there.
The whole system works well for flood up but blowing just nothing!
Have you tried sealing the vent holes? Sounds like when it's pumping the water in the air is getting out so there's nothing to push the water back out the tank?
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Hi,
Yes I have tried sealing the vent holes, the only way I can empty the water via the pump is to break the seal on the cylinder between the 1st and section section.
Strange...
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Does the release valve actually work?
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No evidence at all, it pumps water in well but not out of the tank
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Maybe that valve needs the silicone tube replacing, or maybe the cam on the servo needs looking at. If you get in trouble, let me know...I have the full set of build instructions that came with my Akula, and the diagrams of the valve cam, I can scan them and email them to you if it helps?
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That would be great, a good model if I get it going right.
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Do be aware that if you decide to return it to pressurized system, that hole left in the tank when removing the additional widget will need to be plugged very carefully, respecting the pressures seen in this system, which are quite a bit higher than many other systems.
The original tanks were constructed very sturdily for good reason, as if you calculate 40psi over the area of the tank, the force exerted on the walls is quite considerable, albeit well within the limits of the materials used.
Ideally the hole would be plugged from the inside, but that will be pretty much impossible without cutting the tank open. If patching from the outside, I would make the patch so it forms a ring around the circumference of the tube, like a strap and bonded in with solvent weld or modified acrylic. It won't be as pretty as a new tank, but won't cost much. You can use old PVC waste pipe for repair material.