Hello Steve
Thanks for the data to chew on. If it is as you say easier to get crush depth data on a T-beam style you could use that same data do see what the same size I-beam would be is it was just a T-beam knowing that your structure would be at least that stronge and likely allot stronger which would give you a extra safety factor.
I've been working on a design for a live aboard 80' sea worthy trimaran submarine for a few years now. It would be a bio-diesel, electric sub using Zebra batteries if I can get them. I'd also like the sub to also be pulled by a very large sail kite system.
http://www.gizmag.com/go/3692/
The main center pressure hull can detach from the sponson's and spar's structures that will then be a catamaran. The whole vessel can submerge as one unit to get out of storms or just explore. If the sub ever got flipped over it could submerge and right it self. I was also thinking about having the conning tower be detachable from the main sub and be a mini sub that could be used to escape the main sub in an emergency.
I plan on building two smaller subs before I build the live aboard monster. I'm working on a design for a 20' Trimaran Sub that is diesel, electric and is in the general shape of a canard air craft, so it can be more or less flown underwater with additional flaps for slowing down as well as for fast turning. The sponson's would be soft ballast tanks and the spars can be hydraulically folded back along the sides of the main hull so I can keep the width down to 8' for trailering purposes. The sponsons would also rotate to aline themselves parallel with the sides of the main hull.
On the top side I'm going to do something a bit different then I've ever seen on a sub before. I'll have what looks like the top of a Murceilago Lamborghini car with butterfly doors which is a free flooding space when you dive. In this space you'll be able to drive the sub while it's on the surface with-out the elements getting to you. This area will be partly built from a fiberglass kit car kit. This same basic design once proven in the smaller sub will be adapted to be used on the larger 80' sub as part of the catamaran structure so it can be driven as a separate craft from the main center hull.
There will be a freshwater sprayer system inside this free flooding topside driving area that can rinse the interior after a dive is completed in saltwater or other dirty water dive sites to keep the windows and such clean. I'd also like to add hydraulically collapsible hydrofoils for faster and smoother surface running. Perhaps I'll make this sub have a wave piercing hull. There is a trimaran boat called Earthrace that is pretty amazing.
http://www.earthrace.net/view.asp
Brent Hartwig
From: "Stephen Pearce" <sjpearceqld@bigpond.com>
To: <brenthartwig@hotmail.com>
Subject: RE: [PSUBS-MAILIST] Pressure Hull Support Ring Types
Date: Tue, 9 Jan 2007 11:59:00 +1000
OFF ? LIST
Brent
After following your recent posts it seems that you are enthused by the idea of building a bigger sub that a K 250/350. I am in the process of designing a larger sub my self and would love to know what you have on the drawing board.
You will find that only a small percentage of the list members have an interest in larger vessels but the experience and qualifications held by some members of the group have been an incredible resource.
Just a note on T stiffeners, by understanding is that in order to safely predict the hull crush depth you must know which mode of failure will affect the pressure hull first. If you go down the path of using rolled I beams you will have the added cost of getting an Engineer to assess this type of stiffener. I you use T stiffeners the work has already been done by ABS. The attached spreadsheet created by Dr C Redus is what I have used to workout my pressure hull specifications and (SWD) safe working depth.
I have attached a picture of one of my earlier T stiffener and Bulkhead setups using ABS guidelines.
Regards
Steve Pearce