Questions about diving the U853

[jduncan]

Hello all...

Looking to survey dive the U853 this spring or summer. I have a few questions for people that have been there...

At 130 feet, I can't imagine I would have more than about 5 minutes down there on regular air staying within the NDLs of my computer. I suppose it would vary, but thats what I am guessing...

I'm planning to take my own boat- I've read there are several moorings, is that true? Are there many non-commercial boats that dive the wreck?

Is it worth only going down for a few minutes, or should I train for deco diving before I go?

Jeff

 

[H2Andy]

At 130 feet, I can't imagine I would have more than about 5 minutes down there on regular air. I suppose it would vary, but thats what I am guessing...

have you planned your dive to that depth?

do you have any cotingency gas plan?

have you dived that deep on air before?

will you be diving solo?

have you thought about diving to the conning tower? it's at 100 feet

will anyone stay with the boat while you dive?

 

[jduncan]

have you planned your dive to that depth? Well, that's what I'm doing here - Not on the computer yet.

do you have any cotingency gas plan? Not yet

have you dived that deep on air before? MAX of 111 feet on Nitrox

will you be diving solo? No

have you thought about diving to the conning tower it's at 100 feet ? That's a possibility, sure

will anyone stay with the boat while you dive? Of course

 

[H2Andy]

ok, good to know the last four answers

why not take out the tables or the computer and figure out how long you can stay at 130 max and how much gas you will need to do that and still bring your buddy and yoruself safe to the surface if on your last second of bottom time he should suffer an OOA situation?

 

[wreckedinri]

I dived the u-boat many times in the last 16 years. Without getting into anyone’s qualifications or contingency plans, I’ll let you know what to expect.

A) You will not be alone. The place has become a zoo. So much so that we stayed away from it last year anytime we went to RI. Get there early if you expect to grab one of the moorings. Some years there are up to three.

B) Yes, there is a relatively intact German submarine down there. Big blast hole forward of the sail and another aft of the engine room, starboard side. Swimming through it is like going through a sewer pipe, tight at some spots with some hang-ups. From the blast hole forward to the torpedo room is a dead end. That is, unless you can squeeze through the torpedo loading hatch. Some say that they have done it with singles.

C) You will find darkness. Lots of it. Once in a while, usually later in the year, say in the autumn, you may get a rare day when you will not need a light. Have at least two.

D) The conning tower gets boring very fast. Not worth going all the way out there to look at the stainless steel sky periscope sticking out of the sail if that's all your planning. If you’re not diving doubles, or a 120 and sling, it’s not worth the trouble. Just my humble opinion.

E) If you do go, take a good look at the conning tower, because with all the boats tying off to it, sooner or later it will be torn off and will end up in the sand.

Good luck and have fun,

Dennis

 

[Soggy]

Probably not worth diving on air with no deco. With nitrox 28%, you can get a 15 minute dive in. The max depth is around 125' with much of the dive between 110'-120'.

 

[jduncan]

Great, thanks for the info. I think what we are going to do is a couple dives on the Chester Polling, since we haven't been very deep in New England. It will give some experience in that regard.

When you guys are doing a deco dive, do you use your computer, or do you use the rules of thirds, etc?

 

[Soggy]

When you guys are doing a deco dive, do you use your computer, or do you use the rules of thirds, etc?

Rule of thirds is about gas management, not decompression and is only part of a gas management equation. For generating decompression profiles, I use a combination of ratio deco and modified tables, but decompression diving is something you need specialized training and gear for.

If you are looking to dive the Chester Poling, contact Heather or Dave at Northern Atlantic Dive Expeditions. We are actually going out tomorrow, if the weather is ok (which doesn't look promising). They can also provide you with training should you feel the need to go deeper and stay longer.

 

[jduncan]

Hmm. When I did my advanced OW we did a simulated decompression dive where we used that rule for the ascent. Something like that ....100 feet up to 50 for a few minutes, up to 25 for a few minutes, etc. My Cobra computer has a nice simulator but I don't think I can set the volume of gas - it starts at 2901 psi each time and probably assumes an 80. Maybe we will look into some training for deco diving. Any recommendations other than what you listed above?

No, it's not looking good for tomorrow ...

TONIGHT...SE WINDS 5 TO 10 KT...INCREASING TO 10 TO 15 KT WITH
GUSTS UP TO 20 KT AFTER MIDNIGHT. SEAS 2 TO 4 FT. RAIN LIKELY IN THE
EVENING...THEN RAIN AFTER MIDNIGHT. AREAS OF FOG AFTER MIDNIGHT WITH
VSBY 1 NM OR LESS.
.SAT...SE WINDS 15 TO 20 KT...INCREASING TO 20 TO 25 KT AROUND
NOON...THEN BECOMING S LATE. GUSTS UP TO 35 KT. SEAS 4 TO 7 FT. RAIN
IN THE MORNING...THEN A CHANCE OF RAIN IN THE AFTERNOON. AREAS OF
FOG IN THE MORNING. VSBY 1 NM OR LESS...INCREASING TO 1 TO 3 NM IN
THE AFTERNOON.

 

[MSilvia]

When you guys are doing a deco dive, do you use your computer, or do you use the rules of thirds, etc?

I cut custom deco tables for an "ideal mix" with Vplanner, although I can see where planning using standard mixes definately has advantages too. As Soggy said, don't try planning a deco dive without knowing what you're doing. It's not something you want to be blindly trusting your computer for, and you'll want to have a much better grasp of gas planning than you seem to based on your question about thirds. You need to know what your deco profile will be like before the dive, so you can make sure you have enough gas for you and your buddy to share air for the entire stop if something goes wrong late in the dive.

The last thing you want is to get yourself into a situation where your computer is telling you your decompression stop needs to last longer than your air is going to.