[PSUBS-MAILIST] conical transitions

[vbra676539 at aol.com]

Hmm. I have seen some bolted grain tanks and that sort of thing. I don't see why they couldn't do it the other way. Probably could, come to think of it. They handle big stuff so could probably do bolt patterns and surface machining as well. The problem for local shops would be to handle a structure that size, of course, and the tank fab people would be set up to do it already. I'll bet it isn't as expensive as you think. Maybe less than a used car, anyway, although it might not be much less, depending on the car. You'll learn to love bolted sections, though. Man does it make fit-out easier. Not to mention overhauls.
Vance



-----Original Message-----
From: Joe Perkel <josephperkel at yahoo.com>
To: personal_submersibles <personal_submersibles at psubs.org>
Sent: Sun, Jan 5, 2014 11:00 am
Subject: Re: [PSUBS-MAILIST] conical transitions




Vance,

The cone in consideration is in fact a motor room, with a golf cart motor inside for better air cooling. Also a compressor to finish blowing down the large volume tanks once surfaced, ventilation, and dehumidification equipment all housed. Contemplating all this for a shallow water (250' operational), 36 OD, about 18 - 20' length overall.

Would the same tank fabricators give me internally flanged separating hull sections without sacrificing the kids first car?

Joe

Sent from Yahoo Mail for iPad

            
                
                    
                    
                        
                            
                                                            From:                                                        vbra676539 at aol.com <vbra676539 at aol.com>;                            
                                                            To:                                                         <personal_submersibles at psubs.org>;                                                                                                     
                                                            Subject:                                                        [PSUBS-MAILIST] conical transitions                            
                                                            Sent:                                                        Sun, Jan 5, 2014 2:05:55 PM                            
                        
                            
                            
                                
                                    
                                        
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

                                    
                                
                            
                    
                
            

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