-------------- Original message --------------
From: Brent Hartwig <brenthartwig@hotmail.com>
I was reading a PDF file I have on the Marian S201 and was amazed at the claimed underwater endurance using a large amount of Li-ion batteries. I would like to find out what brand and model of batteries they used.
"Marion S201 sets a new standard in manned research submarine design and operations. This versatile lithium-ion powered submarine can dive to a depth of 305 meters (1000 feet) and accommodate a two man research team for an unprecedented 48 hours duration with a range of 225 nautical miles submerged."
I found some links with more details about this Paul Moorhouse designed submarine.
http://www.promare.org/
Power: Lithium ion batteries Submerged Duration: Forty eight (48) hours @ 5 knots
http://www.submergence-group.com/s201_marion_specs.php
At first I thought and endurance of 225 nautical miles submerged was not realistic, but after seeing the drawings of the sub and it's batteries in the above link, I'm starting to believe it. I've never seen batteries stacked that high in a submarine. If they were conventional lead acid batteries I would think the sub would be to heavy in the rear and not have a good metacentric height. But since Li-ions are a fair bit lighter and it's working, they must of got it right.
There are some interesting pictures in the below link, even though they are a bit small. Near the end t here is a picture of the underside of the sub showing it's galvanized bottom skin and it's free floated formed acrylic fairing in front of the cameras, lights and the only viewport.
http://www.submergence-group.com/gallery/gallery.html
Regards,
Brent Hartwig
From: brenthartwig@hotmail.com
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] S201 Propulsion Data
Date: Thu, 17 Jan 2008 14:29:57 -0800
I found the below information from Marline Submarines interesting.
"A combination of new generation Phosphate-based Lithium-Ion batteries and rare-earth magnet technology main propulsion motor provide performance and endurance remarkable for a vessel of this size and type."
Also of interest to me is that both hemisphere ends are unboltable to make the sub easy to work on. Another interesting design detail is how he designed the side SBT's to attach to the external ribbing. I'm interested to know how he attached and sealed those tanks, since I've been thinking about different configurations to do just that. He might be using some sort of nasty sealant that would make the tanks hard to remove for maintenance. I was thinking of using some sort of gasket, lipped seal, or o-ring. But those can be harder to get a good seal in that sort of configuration.
Frank, you should note that they are using a molded acrylic fairing in fro nt of there forward viewport and cameras, much like you wanted to do.
"Surrounding the forward part of the hull is the bow moulding, the upper half of which forms the bow main ballast tank by means of a GRP inner skin hugging the pressure hull forward hemisphere. This bow buoyancy counteracts the tendency to dive when running at speed on the surface. The lower bow fairing section features a bonded-in acrylic transparent section to allow observation from the viewport whilst maintaining the streamlined hull form.Neutral buoyancy whilst dived is maintained by two internal 1 atmosphere variable ballast tanks with a total capacity of 140 litres, located in the forward pressure hull section. The variable ballast allows some compensation for varying crew and equipment loads. Water ballast is pumped out using a positive displacement pump driven by an electric motor and taken in using external pressure, with impeller pump assistance for surface or shallow depth use."
Regards,
Brent Hartwig