Engel tanks and other piston ballast tank feedback

[wayne frey]

Re: Engel tanks and other piston ballast tank feedback

I just ordered a XP Engel tank with proportional control for one of two projects. If it goes well, I may go with it in the second build also.
Don is sending some Gail 4 inch caps, so we shall see.

[wayne frey]

Re: Engel tanks and other piston ballast tank feedback

So, not too long from now I will be ordering up a dual Engle prportional tank system for the Borei.
At around 700.00 USD, I would like to be sure on what size tanks to get.
Largest "standard " is 825 mil, or 750, next size down, per tank.
Is there a formula for determining correct size, or go with the bigger one? Borie is a 70.5 inch long, 5.5 inch in diameter hull.
Price difference between the 750 and 825 does not matter, really.
I may stuff all this into one, long lexan tube. Or seperate them with a balance tube for connections and stuff.
Opinions and thoughts?
Thanks!

[JWLaRue]

Re: Engel tanks and other piston ballast tank feedback

Hi Wayne,

Best means is to determine the displacement of everything above the waterline.

The way I do this is to first get the desired submerged trim. Then add foam until I have a surface trim. The volume of foam added is the volume required for the ballast tank.

You can do this without the dive module in the hull assuming that you will be placing it such that the top of the module is at or below the surfaced waterline.

-hope this helps,

Jeff

[wayne frey]

Re: Engel tanks and other piston ballast tank feedback

Jeff,
Thanks for the answer. That is the correct way to do it for those following the thread.
I have been jumping ahead, and getting all the electronics, etc, long before the boat is done. I have everything for the X tail, including an Engle. For the Borei, I have ALMOST everything (electronics,etc). In fact, the dual Engles are about all I don't have. So I am a long way from being able to do surface/submurged trim to get the volume.
But, I have enough room to have a crew of gerbles operating it. I could easily go bigger. Would there be any negatives to running slightly larger? Once trimmed, it would still use what is needed,right? The difference might be I could jack the boat up pretty high in the water. Something Russian boats sometimes do.

[JWLaRue]

Re: Engel tanks and other piston ballast tank feedback

No real negative to using larger than needed tanks. My Seehund has excess ballast volume....and since the dive module never goes bone the surfaced waterline, there's no penalty once the boat is trimmed.

I use (one of) the excess to adjust submerged trim to take into account the changes in specific gravity of the water...you know, like between pools and ponds. That's one of the benefits of having complete control over the full range of piston volume. What I call Dial-a-Depth(tm)!

-Jeff

[Guest]

Re: Engel tanks and other piston ballast tank feedback

Couple of things to add here. One AFAIK, Ron Perrott still has a couple of sets of new unusued 750ml tanks up for grabs at half retail price. Secondly if you are able to get hold of some proportional piston tank controllers by Markus Rieger, these have an advantage over Engel and other proportional systems I've seen, because they use a transistorised H-bridge, not relays. On the Version 2.0 boards this gives more subtle control, as the motor is slowed for fine trim which results in less overshoot.

[wayne frey]

Re: Engel tanks and other piston ballast tank feedback

Jeff,
You mentioned checking the Engel with a 110 mm tube. That's id? Is there a source in the usa for lexan that size?
Subculture,
Your link to the company that has 110 endcaps does not have an email adress to it. 110 id?
Just checking options.
Kevin Price has 4 inchers, but maybe I should go a fat as I can for the extra volume the Engel displaces? I have about 5 inches inside the hull I can take advantage of.
Should not have sold my lathe!
See where I am going?

[wayne frey]

Re: Engel tanks and other piston ballast tank feedback

Dave emailed me the WTC in Jeffs boat looks like an OTW. I have sent an email out to see about some WTC's.

[Guest]

Re: Engel tanks and other piston ballast tank feedback

I think you will find it difficult to find metric sized tubing over in the States, same goes for imperial size here in the UK, not that I lament that- imperial measurement was out of date 200 years ago, why do you guys hang-on to that antiquated system, when the rest of the world saw the light decades ago?

If you get endcaps from over here, they're likely to be sized for metric tube. Metric sized lexan tubing is available from UK and european retailers, but be prepared for a price shock- it's lot more expensive over here than in the States, that's why the clear modules from the UK tend to be machined from acrylic/pmma, and if you want something you can bounce off concrete, we use PVC pipe, which is usually opaque but dirt cheap.

If you go larger diameter, you will probably have a lot of the module above the surfaced waterline. That will quickly ratchet up your ballast tank displacement, so bear that in mind.
Engel tanks pull strongly up to about one atmosphere (not far off 90 pounds of force on a 70mm diameter piston), they will keep going beyond that, but will labour and pull quite a bit of current, and you need to consider the hull seal integrity. If you can keep within say half an atmosphere, I'd say you're good to go.

[JWLaRue]

Re: Engel tanks and other piston ballast tank feedback

Wayne,

I obtained the 110mm O.D. tube from the U.K. If I were to source it in the U.S. I would go with either 4-inch or 4.5-inch O.D. and I'd get it from McMaster-Carr.

-Jeff

[Guest]

Re: Engel tanks and other piston ballast tank feedback

You should consider carefully what type of endcaps you wish to use before ordering the tube. Do you want axial or radial sealing?

If you use axial sealing you don't need a lathe to make endcaps, you can bench fit them using hand tools, so long as you're able to cut and file out a circle to reasonable accuracy. You can also bench fit radial sealing endcaps, allthough you will need to work to a much finer tolerance of about 10 thou. If your bench fitting skills don't stretch that far, then stick with axial sealing, or purchase some caps spun up on lathe. I recommend having the caps made to fit the tube if possible- the internal tolerance of extruded tubing is much wider than the external tolerance.

If you go for radial sealing, I would design in some sort of handle or 'ears' on the endcaps so you have something to grip to pull out the encap- the friction of a 4" seal is likely to be considerably greater than for smaller diameter cylinders.