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John Heimann writes:

> I'm interested to hear whether others are using strobes as aids to wreck 
> penetration, and to initiate some discussion of their effective use and
> drawbacks.
> 
> Background:  some wrecks, especially submarines, do not lend themselves to
> using reels for penetration.  An example (which motivated this query) is the
> USS Bass, a V-class submarine sunk in the mid-40's in 160 fsw off Block
> Island.  To access interesting parts of the wreck, one must first enter a
> tight hatch on the front bulkhead at about 150 fsw, where the wreck broke in
> half.  One then can swim around a jumble of machinery in the engine room,
> through another tight hatch into the galley, and another hatch into the
> control room.  Although the Bass is a large sub, there is little room inside,
> only one way in and out, and a lot of silt.
>
> In the Bass, line reels appear to be more hazard than benefit, since the tight
> quarters and twisty path around machinery tend to cause line entanglement.

Although I've never dived a submarine I was inside a WW II sub a couple of
years ago and can understand your problems. There are two submarines which
I'd like dive in the future; one at 45m (150 fsw) near Aberdeen and the other
at 65-80m (215 - 260fsw) off Ailsa Craig in the River Clyde. The second one
will probably have to wait until I do some trimix training although I know
some local divers who are doing it on air. I'd be interested to hear more
of your experiences inside the sub.

> ... we have started to use Ikelite C-Mark strobes at hatch entrances.
> The strobes flash every few seconds, and their light cuts through even fairly
> heavy siltouts.  They are not substitutes for knowing the layout of the wreck,
> but seeing the flashing light certainly adds some comfort when deep inside a
> wreck at 150+ fsw.
> 
> An obvious drawback of strobes is possible failure ...
> ... Finally, the Ikelite strobes tend to float, which
> comlicates their attachment to things.

We use strobes as you describe, but it is an expensive habit. We used
to have 5 strobes between us, we are currently down to three and one is
getting a bit old and one stopped working during last week's dive - I
don't know the reason yet. Of the two we lost, one was attached by velcro
and one by plastic cable-ties. I prefer to use knife straps.

The floating can be compensated by fishing weights. We collect them on
shore dives whenever we see them. Stuart, my buddy, has over 40 pounds
in small weights.

Sounds to me that you should lay a permanent line through the sub. Since
there is only one way in and out, and you are familiar with this wreck, it
shouldn't take too long. I would still use the strobes at the hatches and
carry a safety reel, but it relieves the problem of laying and recovering
line on every dive.

You could leave a slate/sign (with permanent ink) on the inside of the
bulkhead explaining what you've done and asking others to leave/maintain
the line.

Only two other things I can think of in general use of strobes; only light
one path at a time and always collect your strobes on the way out, even
if you intend to return on that dive. Being between two strobes and not
knowing which way is out is like not having direction markers on a
permanent line.

Alan

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