[PSUBS-MAILIST] conical transitions

[David Colombo]

Hi Joe, on the SeaQuestor sub I have a tapered cone attached to the main
hull. Transition is just welded
with no tapered collar. With our std t ribs placed, one of which is at the
transition, the FEA showed no adverse loads down to 1200' on the design
analysis. Since 500' is our planned depth, we decided not to pursue a
transition collar.  David
On Jan 5, 2014 6:06 AM, <vbra676539 at aol.com> wrote:

> Joe,
>
>  Tank fabricators will do a cone with a pre-formed transition knuckle on
> order. It gives you a matched cylinder for your hull. The early Perry boats
> had that sort of thing, although they were fabricated in house and required
> a double weld (at the cylinder and between the knuckle and cone). Later,
> they stopped doing it. That would have added to the expense of fabricating
> a hull, and one supposes that the engineers figured out they didn't need it
> for the pressures in question. Everything they built was limited to the
> double-continental shelf standard (1200 feet or less) except for the 16's
> which required a whole 'nother thought process.
>
>  If Cliff Redus gets back online, you can ask him. The R300 has long
> conical section(s) aft of the crew compartment, and Cliff is an engineer,
> so you have to figure he's been all through this. One other variation at
> Perry comes to mind, which is the 1202. The diver lock out section was 54"
> and the pressure hull was the standard 48" PC-12 size. The DLO has two
> short 48" OD cylindrical sections welded to the elliptical heads of the DLO
> with mating flanges for the motor room and crew compartment interface(s).
> Sort of a step-down, step-up option.
>
>  The PC-18 class of DLO sub was an extension of that. They went to full
> length 54" OD hull for both compartments, ditched the motor room in favor
> of a pivoting 10hp thruster/rudder assembly aft, and got a shorter boat
> with roughly the same displacement overall. NOTE: Based on our experience,
> they also reduced the gas storage and battery pod length, effectively
> shortening mission endurance, but also shortening the boat about 7 feet and
> reducing crane weight by over 2 tons. Not a bad trade-off, and Intersub ran
> the hell out of the 18s, so it must have been a decent compromise. I have
> no experience with them, but the other pilots liked them a lot.
>
>  Vance
>
> _______________________________________________
> Personal_Submersibles mailing list
> Personal_Submersibles at psubs.org
> http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.whoweb.com/pipermail/personal_submersibles/attachments/20140105/3381d635/attachment.html>