Re: [PSUBS-MAILIST] electromagnetic drop weight mechanism

["Phil Nuytten" <phil@philnuytten.com>]

All:

I agree completely with Vance on the electromag weight drop question. The rotation cam-over-center or latch-pivot  operated by a thru' hull shaft has certainly stood the test of time. There are a number of variations including a layered weight plates system  with alternating keyed slots so you can drop just enough to make you buoyant and so on - but I believe the KISS principal very much applies here.

Phil 

----- Original Message -----

From: vbra676539@aol.com

To: personal_submersibles@psubs.org

Sent: Sunday, January 15, 2012 6:03 AM

Subject: Re: [PSUBS-MAILIST] electromagnetic drop weight mechanism

There are substantially more cons than pros here. Many of the deep vehicles and early attempts used this, including the old Deep Jeep, Alvin, and the Trieste. Read up on any of them and you will find instances where an unexplained short dumped everything and sent them to the surface. Expensive and wasteful is what it is. Especially Trieste, which had its BATTERIES held on sloping rails (they were deck mounted, originally) and lost them ALL due to a very minor short circuit in the cabin. Lost them all at 15,000 feet, that is. My friend Mike Stahle was the chief pilot and then crew commander for that thing, and they hated those electromagnets. Hated them! Necessary for them, of course, but for us, a penetrator is just too dead easy to install--and bullet proof. Turn handle, drop weights. Don't turn handle, take weights home. Simple.

Vance

-----Original Message-----
From: Alan James <alanjames@xtra.co.nz>
To: personal_submersibles <personal_submersibles@psubs.org>
Sent: Sat, Jan 14, 2012 8:46 pm
Subject: [PSUBS-MAILIST] electromagnetic drop weight mechanism

Hi all,

Haven't designed my drop weight mechanism yet, but are toying with the

idea of using electromagnets.

Was looking at some gate holding magnets that had a holding force of 1200 lb &

a draw of only 500mA off 12V. They were a tad expensive so will look for an alternative.

The positives I see are that the system would be easy to put together, (possibly with multiple

magnets for making the weights more manageable), & you could drop your

weights very quickly.  The negatives are you would not want to turn the power off before

you were on land & you would need a system of locking the weights in place for transport

or alternatively remove them.

Is this system used elsewhere, any thoughts??

Alan