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Re: [PSUBS-MAILIST] Drop Weights
Well, there IS the Gulf Stream to carry that stuff, and you live on the East side of it, the last time I checked. Maybe they're coming from Havana? However, somebody somewhere gets them. If we don't find them on the web, we'll ping on Phil the end of the month. Maybe he'll know. Meanwhile, I'll call Pete Hoffman and maybe HBOI (if there is anyone left up there who will talk to me). Otherwise, maybe I can set up a cheap-o distributorship. Carsten might help. Those things are way too handy not to have.
Vance
-----Original Message-----
From: Jay K. Jeffries <bottomgun@mindspring.com>
To: personal_submersibles@psubs.org
Sent: Tue, Sep 15, 2009 6:57 pm
Subject: RE: [PSUBS-MAILIST] Drop Weights
There has to be a source in the US for that product or a similar one as we find the floats washed up here on the beach all of the time.
R/Jay
That's all I see for the moment. Let me make a call.
Can you suggest a source in the US? I am only finding mostly European sources.
You're welcome. And besides, those Nokalons look really offshore hanging in the garage. No one else has them except the net fishermen.
Vance I think we should keep you around. That is a good plan. Just about every time I do
something permanent like, I seem to regret it a little later or at least a better solution.
In a message dated 9/15/2009 12:50:52 P.M. Central Daylight Time, vbra676539@aol.com writes:
Syntactic--is that a trick question? Before getting into all that mess, I'd recommend taking your best SWAG and order some Nokalon buoys. Get the kind with the hole through the middle and you can string them on a pipe like beads on a necklace. They come in all sizes and depth capabilities. Get the ones that are 9 or 10 inches across. They won't be pretty, but you can add plenty of buoyancy mighty quick with them, and figure out in the process if the solution you need should be more permanent.
Vance yup she be fun. Lets see how you spell syntac foam
In a message dated 9/15/2009 12:23:41 P.M. Central Daylight Time, vbra676539@aol.com writes:
Will 200# compensate for your VBT. If that's your only external void, then it should be enough. If you are already running short, however, then you're going to be thinking about auxiliary flotation pretty soon, too. Hmm. Lots of problems. Fun, ain't it?
I am not real sure on this. I wanted to have a 200 lb drop weight. Just seems like a good
number to me. My sub is very stable and I am quite sure would not be a problem. I do however
want it located close to my CG so I come up level. This problem I must solve this winter as
now I only have about 110lbs to play with and it is not at my CG. Not to mention I do not
have my arm on and several other little goodies.
Must be real nice having that much to play with. Ah to have it to do over hehheh
In a message dated 9/15/2009 10:54:48 A.M. Central Daylight Time, ShellyDalg@aol.com writes:
Dean, you mentioned that your drop weight was not very big and the front was a little light.
It started me thinking about the size of my planned drop weight. I've read about a lot of subs and there doesn't seem to be a lot of commonality in percentage of drop weight used for the various sizes of psubs.
I remember the little video about towing the Delta sub and during the submerged part of the video they said it had a 40 pound weight that could be dropped.
Other subs had drop weights that ranged up to 400 pounds.
I wonder if there's a danger in having too big a drop weight. Can it cause problems when it's released?
An advantage to a large drop weight would be that when dropped the sub would have more buoyancy and be able to "tear free" from a minor entanglement like the kelp we have around here.
The disadvantage could be a too rapid ascent and maybe some instability once you reached the surface.
Both of these could be quite dangerous.
The surface instability may not be that critical because at least you're back up where you can be reached by the surface crew and a line can be attached to the sub.
The uncontrolled ascent rate is the thing that I was worrying about.
I had planned on a pretty large drop weight. More like 750 pounds. The drop weight mechanism is designed in a keel shape, and has a bunch of wheel rollers so I can roll the sub around when it's on the floor in the shop, and when launching the sub it can roll on and off the trailer.
The actual lead weights will be shaped to fit inside the steel keel form and bolted in. The total weight can then be adjusted by adding/removing weights but the steel keel mechanism itself weighs about 250 pounds.
The total lead ballast needed to sink the sub is going to be close to 1800 pounds. Most of this is bolted to the floor inside with some of it on a sliding mechanism to adjust trim angle.
These are rough numbers at this point of the build and my float test will determine exactly how much is actually needed depending on what all I put into the interior of the sub.
Adding a passenger, equipment, and later improvements like a manipulator arm or whatever can be compensated with the underfloor weights.
In the model testing I did the sub wobbled during ascent when it was simulated dropping the weight but it stayed level and fairly stable on the surface. It's the wobbling when coming up that concerns me.
Anybody got any thoughts on this?