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Re: [PSUBS-MAILIST] PC-1402 Conning Tower Dimensional Drawings Uploaded




Vance,

According to Stachiw the cylindrical acrylic performs worse than disc or spherical in terms of optical, but he doesn't really give a description of how bad it is. The larger the diameter, the less optical distortion is perceived. He states that a diameter of 42 inches, 4inch thick, has acceptable optical qualities. The fabrication of an acrylic conning tower however appears to be much less involved than a steel conning tower with multiple disc viewports.

Jon


vbra676539@aol.com wrote:
Steve and James,

If you go to the Submersible Systems Technologies web site and look at the Vista Ranger, you will see a good picture of Steve's hatch, or at least of the PC-1402's hatch, which they used on the new acrylic cylinder conning tower. I do like the idea (the acrylic conning tower) but wonder about distortion and crash protection. I have, in fact, seen some used in pretty rugged circumstances, so I may be just hanging with what I know.

For instance, Vickers built the LRs based on Perry's PC-15 dimensions. The hulls were spun fiberglass and the conning towers were all acrylic like you see on the Ranger. The crews ran the hell out of them (we were all in direct competition in those days, and we ALL ran the hell out of whatever we had). In any case, Vickers never had any trouble with the LRs that I heard of aside from the fact that they were tubby as all get out and hard to manage in cross currents and the like. The subs had crash guards on deck to help protect the acrylic, and they were monumentally heavy. To be fair, they did have the spare payload, so I guess it worked out. Just on the face of it, the acrylic tube looks to me like simpler construction, and maybe even cheaper than the Perry's as you don't have all the multiple bits and pieces to build and weld and machine and clad and paint and...well, and so on.

Mind you, the PC-12 class from Perry has continued in service (in the tourist industry mostly), and they have done, literally, tens of thousands of dives without incident. That's a hard record to beat for sheer toughness. Keep in mind, you don't wear dress shoes when you're working. You wear steel toed brogans or work boots--heavier, more expensive perhaps, but very hard to beat when you drop a hammer on your toe. The steel conning towers are kind of like that, I think. Sort of a Wolverine safety boot with viewports.

Vance





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