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Author Topic: OTW Vanguard help  (Read 78521 times)

thegrimreaper

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Re: OTW Vanguard help
« Reply #25 on: November 11, 2011, 08:39:51 PM »

quick question how/what to use to bond plexiglass ???

Mark
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Andy_k

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thegrimreaper

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Re: OTW Vanguard help
« Reply #27 on: November 11, 2011, 09:58:08 PM »

thanks Andy problem with it is that it says for indoor use only me thinks its not meant to get wet if so then I cant use it on my ballast tank

regards Mark
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Sub driver

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Re: OTW Vanguard help
« Reply #28 on: November 12, 2011, 01:19:06 AM »

look in your yellow pages for any local plastic acrylic sign makers and pop along to them and purchase some of there glue. they use it in bucket loads . regards sub
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Andy_k

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Re: OTW Vanguard help
« Reply #29 on: November 12, 2011, 06:49:46 AM »

Hi Mark I have used this when I made the WTC for my akula where the ballast tank ends support the end compartments and had no problems with it being effected by water
once dry it is like the plastic itself  :-))
Andy
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thegrimreaper

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Re: OTW Vanguard help
« Reply #30 on: November 12, 2011, 10:11:14 AM »

cheer guys that two options open to me

Regards Mark
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Circlip

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Re: OTW Vanguard help
« Reply #31 on: November 12, 2011, 10:35:15 AM »

Meant to post this after reply #24, "And the weapon of choice for glueing Acrylic/Perspex/Oroglas is Tensol for all applications."

  Regards   Ian.
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Subculture

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Re: OTW Vanguard help
« Reply #32 on: November 12, 2011, 10:44:25 AM »

If you're butting up the outer disc to the end of cylinder via an o-ring seal (axial compression) the inner ring is just acting as a mechanical 'stop' or key. Therefore the inner disc doesn't actually need to be watertight. Does that make sense?

Three or four nuts and bolts around the edge (not too close) should keep the two discs together without the need for any solvent or adhesive. To seal these bolts squirt a little mastic (silicone or acrylic) into the holes before tightening up. Brass or stainless steel countersink bolts will look neat and tidy and shouldn't corrode.

Circlip

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Re: OTW Vanguard help
« Reply #33 on: November 12, 2011, 11:05:00 AM »

Yep S/C quite correct re the seal. If push came to shove and an O-ring of the correct size was unavailable, a flat ring of sheet Rubber or Silicone could be used.

  Regards  Ian.
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thegrimreaper

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Re: OTW Vanguard help
« Reply #34 on: November 13, 2011, 09:48:30 AM »

Was thinking along the lines of silicone on the inside disk for the ballast tank with 4 rods end to end of the tank I think that would hold it together will be pressure in the tank when full so need that to be sturdely held as to the other sides of the disk was thinking of pinching/using  the way that my Sheerline Akula is done again with 4 rods from each end going to the respective end of the ballast tank so that if access is needed to the rear motor  compartment I would have to undo 4 nuts and only the rear compartment would come away. end caps are 6mm plexiglass so having 8 small holes around the out side shouldn`t put to much stress on the endcaps of the ballast tank. Any corrections to this idea would be greatly welcome

Regards Mark
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Andy_k

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Re: OTW Vanguard help
« Reply #35 on: November 13, 2011, 10:11:42 AM »

you would need to seal the threads on the rods as these will leak under pressure not sure if the silicone would hold the pressure but you could assemble it and pump water in and test it under pressure this what I did when I tested mine but I used tensol to glue the tank ends on  O0

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Subculture

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Re: OTW Vanguard help
« Reply #36 on: November 13, 2011, 10:38:34 AM »

Are you running the rods external like Sheerline, or internal like Andrew is doing?

Worth mentioning that OTW use three rods in all their WTC's- a three legged chair/stool always finds it's own level.

thegrimreaper

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Re: OTW Vanguard help
« Reply #37 on: November 13, 2011, 05:48:20 PM »

Thanks Andy_k for the photo but was thinking of rods on the outside of the tank.

Andy Subculture chairs/stools ??? ha ha. I know what you mean Andy but would that work/be ideal with the rods externally fitted ???

Regards Mark

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thegrimreaper

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Re: OTW Vanguard help
« Reply #38 on: November 13, 2011, 05:53:41 PM »

I am planning on making the ballast tank around about 20cm long which if I have read earlier post correctly will mean that the whole sub will be lighter to lug around then when put in the pool/pond water can be taken on to lower the sub to the correct water line have I read that right ???

Regards Mark
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bonehead

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Re: OTW Vanguard help
« Reply #39 on: November 13, 2011, 07:03:28 PM »

I am planning on making the ballast tank around about 20cm long which if I have read earlier post correctly will mean that the whole sub will be lighter to lug around then when put in the pool/pond water can be taken on to lower the sub to the correct water line have I read that right ???

Regards Mark

My water tank is 220mm long but the boat still sit's about 10mm to low in the water compared to the real thing. This I think is because I have a large diameter tank which means that there is a sizeable section of wtc above the water line on the surface. I reckon that with a smaller diameter to that which I chose could have meant less wtc above the water line, batteries under the tank and a smaller volume water tank needed to get her under. I've tried all way's to get the correct water line but have had to sette for that which I have, resulting in about 95% of the tank being filled to get her fully under - not to mention the fore/aft trim prob's due to the front mounted lead acid gel battery. I am certain Andy will have a suggestion/solution!!
All the best
Jim





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thegrimreaper

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Re: OTW Vanguard help
« Reply #40 on: November 13, 2011, 08:02:08 PM »

Jim thanks for the measurement Andy did mention placing the batts in the front and rear compartments also because I have opted for the 10cm tube that will/should help with the waterline

Regards Mark
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swedishprojectbuilders

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Re: OTW Vanguard help
« Reply #41 on: November 13, 2011, 08:55:30 PM »

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Subculture

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Re: OTW Vanguard help
« Reply #42 on: November 13, 2011, 11:00:13 PM »

Sounds good to me.

thegrimreaper

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Re: OTW Vanguard help
« Reply #43 on: November 14, 2011, 11:45:21 AM »

Andy (Subculture) would three rods on the outside of the WTC hold everything in place??. I have got 3 X 1m zink plated 4mm threaded rod would they do the job ??. Thanks in advance of your answer.

Regards Mark.
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Subculture

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Re: OTW Vanguard help
« Reply #44 on: November 14, 2011, 12:23:56 PM »

Three rods will be fine. Zinc plated threaded rod will corrode if it's in the wet though, stainless is best, or you can use brass rod.

Subculture

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Re: OTW Vanguard help
« Reply #45 on: November 14, 2011, 01:07:28 PM »

Don't forget the 10cm cylinder has to sit really low, ideally flat on bottom of the hull in order for none to project above the waterline if you're hoping to minimise the size of the ballast tank and achieve a true scale waterline.

Modern Brit subs seem to be a cross between Russian and U.S design principles- we employ single skinned hulls with forward and aft free flood areas, like the Americans, but favour the high freeboard that Russian boats have.

If you're running the rods externally, that is going to increase the height of the cylinder by at least 6-7mm, so it's pretty likely that the cylinder will poke a bit above the waterline. With a 20cm long tank, assuming your pump can fill it to 75% capacity, that gives you about a litre of displacement. The Vanguard needs about 750-850ml to lift the top hull, sail, vanes and rudder above the surface to scale waterline. I've allowed a 10-15% fudge factor, as hand laid GRP hulls can vary a bit. So you have about  150-250ml in hand.

Lets assume your cylinder is 100cm long, 5mm projecting above the waterline will require about 150ml of extra volume in your ballast tank. Should be okay with that.

If it projects 10mm above the waterline, you will need an extra 400ml. Now you're going to be in trouble. So watch that height so things don't get out of hand.

thegrimreaper

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Re: OTW Vanguard help
« Reply #46 on: November 14, 2011, 02:43:53 PM »

Sorry Andy I am getting lost here now I am using 1000mm tube as apposed to boneheads 1100mm. Jims ballast tank is 2200mm long and he has problems getting the sub to scale water line, question is do I need to go bigger or smaller on my ballast tank to get a truer waterline. Maybe I miss read earlyer posts but I thought if I went with the smaller tube their would be less of the WTC poking above the water,so I would need less pumped water to submerge the boat,and therfore could get away with a smaller tank. Headache comming on here  ;)

Regards Mark
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Re: OTW Vanguard help
« Reply #47 on: November 14, 2011, 03:46:43 PM »

With the OTW module, even if you drop it as low in the hull as possible, you will still end up with about 10mm poking above the surfaced scale waterline. Hence you need a bigger tank to get the boat under, or accept a lower waterline.

With 100mm diameter tubing, you should just about be able to avoid this,  but it is literally 100mm from the bottom of the hull to the  waterline, so with the rods running externally like Sheerline, as opposed to internally like OTW this effectively makes your tube fatter, because you have to allow for clearance for the rods- does that make sense?

It's quite likely that a little bit of the tube will now sit above the water surface, and I was demonstrating how this will affect the volume of the tank.

thegrimreaper

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Re: OTW Vanguard help
« Reply #48 on: November 14, 2011, 07:41:51 PM »

Right thanks Andy got it now looks like I will be changing to internal rods in brass then Thanks again Andy your help is greatly appreciated

Regards Mark
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Re: OTW Vanguard help
« Reply #49 on: November 14, 2011, 07:59:22 PM »

That will give you a possible issue with sealing the rods where they run through the ballast tank.  %%

Always something eh?!

I would still run the rods externally, but position them so they're not near the bottom of the tank, and trim the bottom of the disks so that they are level with the cylinder wall. That way the cylinder can sit as low as possible.
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