|
Joseph Perkel,
You do make some apealing designs,
Sir...
First on diesel boats.
Modern navy diesel submarines always use one or a
number of diesel gennerator sets. The single propeller is always
powered only by one big electric motor.
The electric motor is much more powerful than
the gen-sets - and gives the dieselboat nuclear speed in short bursts -
short because of the inherent
limitations in battery power. The most advanced
navy boats combine this with an AIP system ( se my note on this
)
This engine arrangement is dictated
by tactical considerations that has little no application in a
civilian boat - if copied strait over it will be inefficient and expensive - and
poorly suited to furfill its recreational mission.
A diesel Psub however do have some very nice
features...
1. It can make long surfaced voyages at speeds
in the 6 - 9 knots range.
2. It can recharge its batteries,
3. It can recharge its hp air
tanks.
4. Its battery drive becomes secondary - and can be
very small without compromising the boats capasities.
A diesel Psub makes transit on surface, and moves
very slow and with limited range submerged. This works very well with the
recreational mission it has. In other words you need a lot of diesel power - and
diminutive electric power.
Imagine you purchase a standard marine engine -
with a reduction gear and clutch. Via standard motorboat parts it spins a
propeller. With that in your boat you have very long surfaced range. Expect
to use about 1.5 to 3 kW dieselpower pr. ton of boat. Then you
add a small DC motor with a V drive belt to the propellershaft. Expect to
use about 0.5 to 1.0 kW pr. ton of boat. Ideally its 12 or 24 volts - and
simply uses the starter battery of the diesel motor ( not a standard one -
a BIG traction type forklift battery - it will
kick your diesel back to life when surfaced ) The diesels built in alternator
takes care of charging the hole thing.
Its that simple !
If you wish for a little more trouble - and a
little more NR-2 style - just forget the V belt and use electric thrusters like
on K-250 boats.
One note on surface performance...a surface ships
speed it dictated by its length. The longer the faster. That is why
Kraka is 12.6 meters - it makes it possible to travel at 6 knots with
just 16 horsepower in a 6.5 tones submersible.
As for trailers...I can understand all the reasons
for the concepts popularity - you drive to you dive location because a
K-250 is not a boat that is easy to sail over any distance. However it
puts severe constraints on the submarine designer. Length - displacement -
all is limited by the trailer. If you put your diesel psub in a marina and
make your transit not by road but by sea - all this falls away and the size and
endurance of the boat explodes.
One more thing - a diesel boat is
warm. The Kraka´s motor is water-cooled
- but it heats the interior of the boat to a nice level in Scandinavian
waters - and when dived the hot motor block keeps the temperature nice for
quite some time.
I don't mean to say that the special way we operate
Psubs in Denmark is better or smarter than the small electric subs on
trailers - that type has it own set of features. I often dream of building
a very deep diving boat like that. But - I must report that our diesel
engine concept works, and works well. If I wish to play submarine, I jump
on my bicycle, go to the harbor and a few minutes later I am at
periscope depth. Or, I tour the capital of Denmark with is harbor and
canals as a surface boat. In the world of psubs - going diesel is analog to the
revolution of nuclear power in navy boats - you get a hole new level of
range and comfort.
Regards,
Peter Madsen
Jeg beskyttes af den gratis SPAMfighter til privatbrugere. Den har indtil videre sparet mig for at få 14357 spam-mails Betalende brugere får ikke denne besked i deres e-mails. Hent en gratis SPAMfighter her. |