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Carsten, Thank you for your reply. Review of sub strandings over the last
100 years reveal that immediate escape is the best option while the
crewmember(s) are still fresh. Stress, tiredness, cold, and CO2
build-up all contribute to a rapidly decreasing chance of a successful
escape. In addition, it seems when you have one accident others seem to
cascade. This is not just from my review of history, there are other
papers that have come to the same conclusion. You can always go back and
get the sub later (as they did with the I really love Sgt. Pepper
but the issue of freeboard on the surface makes entry and exit very difficult
as you note. From your recent account, I gather that you lifted the
submersible back onto the trawler prior to exiting the sub…please
confirm. As to Sgt. Pepper vs. Nemo I don’t really remember the
size of Nemo but would guest that
there is a significant difference in size between the two. Skin area and
cross sectional area are major factors in frictional drag…if you double
speed, drag increases 8 times. As to size differences (don’t have
the rule of thumb right in front of me but believe it is), if you double the
size of a vessel, the frictional drag increase by a factor of 4.
Appendages do cause drag but at the nominal speeds that most PSUBS operate at,
the drag is a small factor in the overall picture. If you want to
radically increase speed, then the hull needs to be VERY FAIRED. The German
Type XXI Electro Boat was a very good example (Walther’s hydrogen
peroxide powered sub even more so), this was a radical change in form from the
earlier fleet type boats. In Sgt. Pepper’s
case in the open sea, what happens if you can’t mate back up with the surface
support vessel? R/J2 Respectfully, Jay K. Jeffries Andros Is., It is the mark of an educated mind to be able to entertain a thought
without accepting it. - Aristotle Hi Jay - that is a question raising my attention. On Peppers sub, Emile
and I have the possibilty to release three screws on the front dome, relase the
inside scuba gear from the dive system and the wall. Open the snorckel vale and
flood the boat via a pipe from the snorckel breazing vale to the bottom of the
pressure hull via a hose to make the pressure comensation to leave the boat. It the boat catch a net on a wreck - what will be the time to leave-
After an half hour and all thrusters now hopeless in the net - the pilot fresh
and clear ? Or after 8 hours - the Co2 monitor showing some alarm at 1-5 %
Co2.. ? I was under the impression that the latest point on day light will be
the best so the guys on the surface can do some rescue operations... Item to be discuss.. Ps about drag.. If Nemo with his three motors and two sail is under
full speed underwater - Peppers can turn cyles around this sub like a shark..
with one Minkota 55 lbs. And in the afternoon when Nemo is on the pier and
chargeing his batterys - Peppers switch on the light fo a late night dive - and
that with the smaller battery.. But in my opinion a open sea psubs needs a sail - or a supply boat with
a good working crane. best regrads Carsten |