From: "Peter Madsen" <peter@submarines.dk>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: Re: [PSUBS-MAILIST] Collision with surface vessel
Date: Wed, 9 May 2007 11:26:23 +0200
Thijs,
Mostly we operate a very low speed...in recreational waters...but a silent
sailboat still is a problem. Back when I sailed with Freya in 2002 - I used
a diver buoy exactly like you describe. It was bright yellow and hade a big
diver flag on it. Unfortunately it attracted recreational boats much more
than making them stay clear - so I stopped using it.
Once you get hit - it really doesn't matter who were right and who were
wrong in accordance to maritime law.
I like the idea of using hydrophones and visual systems since I feel its us
- the submariners - not the other recreational and commersial vessels that
must prevent this problem.
Regards,
Peter
----- Original Message -----
From: Thijs Struijs
To: personal_submersibles@psubs.org
Sent: Thursday, May 10, 2007 9:37 AM
Subject: Re: [PSUBS-MAILIST] Collision with surface vessel
Peter,
I presume that when you surface you have some speed and you operate in
waters were you have to deal with big and noisy ships.
For small subs, operating in recreational waters and surfacing at zero
speed i was thinking of a buoy as used by scuba divers. The
(pressure-resistant) buoy should be attached to a 5 mtr. line. When
surfacing you could wait for let's say a minute at 5 mtr.depth before
comming to the surface. This works for scuba divers, so why should it not
work for subs. If you combine the buoy with a flashing light and a rotating
camera it should work even better.
Regards,
Thijs Struijs
----- Original Message -----
From: Peter Madsen
To: personal_submersibles@psubs.org
Sent: Tuesday, May 08, 2007 11:06 AM
Subject: Re: [PSUBS-MAILIST] Collision with surface vessel
Jay,
Kraka, the diesel-electric boat I pilot have both up looking windows
and features a periscope. This is based on four cameras each covering 90
deg of the horizon. By choosing to look a say camera four I know that I am
looking aft while no two give me the starborad view - and so on. My idea
for the final solution on the collision problem was to make a buoy with say
60 feet of cable on it. Its formed like a long pole with the four camera at
the top, a flotation device at the middle and ballast at the bottom. Poles
standing in the water like this can be quite stable ( provided the uboat
don't make way )
My experience is that anything on as submarine must be made with great
care. We have had many problems with flooded GPS antennae, moisture in the
periscope and broken diveplanes ( they protrude ) and the answer is always
to make things better, stronger and more carefully. Most of these problems
have solutions that can not be found at the drawing board alone.
Solving it - is half the fun...
One of our special problems is that our boat in only drydocked once a
year so many improvements or repairs comes only in these service periods.
One of the features of a trailer based submarine is that it sits in your
living room...most of the time. This is just not the case wih Kraka.
Regards,
Peter
----- Original Message -----
From: Jay K. Jeffries
To: personal_submersibles@psubs.org
Sent: Wednesday, May 09, 2007 1:43 AM
Subject: RE: [PSUBS-MAILIST] Collision with surface vessel
Peter,
I agree with you that a collision on or near the surface is one of
the most likely major accidents to happen to a PSUB. This is supported by
submarine history demonstrating that this is one of the largest causes of
submarines under peace-time conditions.
The ABS included the requirements for a small porthole in the hatch
so that you could look up while approaching the surface and hopefully see
the shadow of a vessel overhead that is silent or stopped. Larger
submarines with a periscope have the capability to train the scope's top
lens upwards to accomplish the same feat. Many sub's operating procedures
include a pause in ascent near the surface to look and listen for other
vessels in the near vicinity.
If you do not have much internal noise in your PSUB, you should hear
most power vessels while still at some distance. A trainable hydrophone
will help discern the direction. The cabled camera is a good substitute
for a periscope but will be difficult to obtain a stable image with known
viewing direction on the surface. Just remember that gadgets just require
more maintenance and can detract from pleasurable operating time.
R/Jay
Respectfully,
Jay K. Jeffries
Andros Is., Bahamas
A skimmer afloat is but a submarine, so poorly built it will not
plunge.
From: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Peter Madsen
Sent: Monday, May 07, 2007 6:28 PM
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] Collition with surface vessel
Hi Psubbers,
When people talk of submarine safety the situation most often
assumed is a sub in distress on the seabed. This is of cause a very
critical situation,
and we all design boats that are redundant in many ways so that we
hopefully never get in that situation.
In my practical experience - however - getting hit by a passing
surface vessel when being at or very close to surface is a much more likely
incident. Depending on the speed and size of the vessel and submarine any
level of damage is possible - and the sub I likely to sink with its
pressurehull ruptured to some extent after the collision.
We are currently adding hydrophones to Kraka for detection and
classification of surface sound contacts, and we are designing a cable
camera for the UC3 - that can be send up prior to surfacing. We hope these
technical gadgets may make it more safe to operate our subs.
The professionel submariners ( navy ) that I have talked to say that
they solely depend on their passive sensors - hydrophone arrays - and they
have zero way of detecting a drifting - stopped or sailing vessel.
What do other non navy submarine operator do - how do you psubbers
handle this safety issue ? Most people ask me why we don't just have an
underwater radar ?! - or is it sonar - a sea surface hull detection
device...like the navy...
Well - what do you do ?
Regards,
Peter Madsen
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