Any U-853 experience you want to tell.

[ScubaSarus]

Scheduled to dive the U-853 for the first time Saturday. I am quite excited since Ive wanted to dive it for 6 years.

I'de like to hear peopl'es experience diving it (thoughts, logistics, sentiments etc) I know some never made it after 6 attempts due to weather or other problems. But for those who did, what was the experience like ?

Chris

 

[gstroupe]

I hope you get some good responces, I'm interested in diving it before the summer is over!

 

[matt_unique]

I have made 15 dives on the U853, 6 of which have been deco. It is amazing how much it has changed over the last few years. I can imagine how dramatic the change has been for those diving it for the last 30 years.

It is awe inspiring the first time you see this wreck with your own eyes. You definitely "feel" this wreck - the history - the horrible mission - the horrible end. Everytime I dive this wreck I use every single bit of free space in my log book to describe it. I'm planning to dive this wreck and others in the BI Sound weekend after next weather permitting.

Vis is varied. A month and a half ago I had 20' of vis with no current. I have also experienced 5' vis and current such that you had to go hand over hand along the wreck into the current.

Head 150 degrees to get to the bow and 330 degrees to get to the stern after you descend on the wreck. There are two 45 degree angled torpedo loading hatches near the bow and stern which can be confusing. Use your compass to orient which portion of the wreck you would like to visit. For non-deco purposes you have time to descend the conning tower mooring and visit the bow and back, or to the stern and back. It takes two non-deco dives to see the whole thing. The very front tip of the distinct bow broke off 2 seasons ago and lays in the sand just in front of the wreck. Very interesting to see the very tip of the bow. The stern section has broken off but it lays in place. I use the analogy of a broken pretzel with the pieces in the right place. You touch metal at about 95' on the conning tower give or take a few depending upon the tide. You cruise the top of the structure at about 118'. It's about 125' to the sand.

If you're planning your profile I would suggest 118' for your first dive. A few points of interest....the tip of the bow (in the sand as I mentioned above), the forward port torpedo doors are open with a torpedo still in place. Though it does not look like a missile as one would expect. The bow planes on each side of the wreck are interesting. The very stern is interesting. Of course the two large blast holes, one being just forward and to port of the conning tower and one toward the stern. Also take a look at the very top of the conning tower for the periscope. The stainless steel still shines as though it were brand new - amazing to see this.

Bring lights in case you have bad vis. Some people like to use reels with bad vis but you can't get lost if you remember the compass headings I mentioned above. As with any wreck keep an eye out for nets above and beside you. The last time I was there nets were not a problem at all.

From CT you will have quite a ride but it will be well worth it. Take your time and enjoy the experience. Any jitters you may feel will likely be overcome by a sense of awe if you have the experience, training, and gear for this dive.

--Matt

 

[ScubaSarus]

Thanks Matt Those compass headings are great to know I'm bringing a dive slate and I can actually sketch a diagram with your info.

Chris

 

[JimJam]

what's acceptable for air supply...I assume doubles are preferred, but would an AL 80 suffice? I know newport divers insists on a pony bottle as well...

 

[sean22]

Good luck with your dive. I have been diving the 853 for about 15 years. It is a awesome and thought compelling dive. I have the benefit of living only 16 miles from the site(Jamestown RI) and it is a fairly short run in my diveboat. For a detailed description of the site, you might want to pick up a copy of RI Adventure Diving
(Ok that is a shameless plug as I wrote the chapter on the 853). Seriously though
have a great time and I hope you have great weather. We will be out there this weekend, diving the Grecian and the Idene. One tip I would give is that if it is possible, dive it on a weekday if you can. It is a zoo on the weekends.

 

[Soggy]

I'de like to hear peopl'es experience diving it (thoughts, logistics, sentiments etc) I know some never made it after 6 attempts due to weather or other problems. But for those who did, what was the experience like ?

Yeah, that was me. I finally got out a couple months ago.

Advice...bring a good light and a good buddy team. While technically still in recreational depths, it is not a recreational dive, IMO....it's deep, very dark, very silty, low-vis and has lots of current. Do some serious gas planning ahead of time, as one should do with any dive, but it's especially important on the deeper dives here.

When you get to the bottom, make sure you are positive which line you came down....there are a bazillion ghost lines from old moorings and you don't want to come up the wrong one....

It's an amazing wreck and I can't wait to dive her again. Due to the fact that it's a submarine, it's basically impossible to truly get lost unless you start spinning around in circles.

 

[Soggy]

what's acceptable for air supply...I assume doubles are preferred, but would an AL 80 suffice? I know newport divers insists on a pony bottle as well...

An al80 would be absolutely unacceptable in my opinion. Let's do a little math to determine your rock bottom (minimum gas supply required for ascent).

130 ft = 5 ATA

assume one out of gas teammate w/ both teammates breathing at a SCR of 1 cft/min (not unreasonable)

Assume a minute at the bottom to solve the emergency (5 ATA)
a minute to 100 ft (4 ATA)
a minute to 70 ft (3 ATA)
a minute to 40 ft (2 ATA )
a minute to 15 ft (1.5 ATA)
3 mniutes at 15 ft for a safety stop (1.5 ATA)
a minute to the surface ( 1 ATA )

I've done some good rounding to make the numbers easier to crunch, but we can reduce this to:
-1 minute at the bottom ( 5 ATA ), so 5 cft/min per diver x 1 minute = 10 cft/min
-from the bottom to 15 ft is an average depth of about 3 ATA (actually, a little deeper than that) for 4 minutes, so 3 cft/min per diver (3 cft/min * 2 divers * 4 minutes = 24 cft)
- 3 minutes safety stop ( 1.5 ATA ), so 1.5 cft/min * 2 * 3 minutes = 9 cft
- 1 minute to surface ( 1 ATA ), so 1 cft/min * 2 * 1 minute= 2 cft

So, we need to leave in reserve 10 + 24 + 9 + 2 = 45 cft of gas just to ascend safely if one buddy goes OOG. That's 1750 psi in an Al80! That leaves 1250 psi (32 cft) for the descent and dive. Assuming a liberal SAC rate of .6 (I would plan for .75), that's about 10 minutes at the bottom, minus the time/gas it takes to reach the bottom...and that's if you start with 3000 psi!

IMO, there is no way to do a dive at this depth safely without either a very large single or doubles. The planning I did above was very conservative, partially to make the numbers easier to crunch. The max depth is actually more like 125, and you could reasonably do the entire dive at around 115-120, but this only reduces the gas requirements by a few cubic feet. While a pony bottle may (arguably) add safety in that you have extra gas should it be needed, you cannot *plan* on using that gas, so it doesn't change the numbers above.

 

[matt_unique]

what's acceptable for air supply...I assume doubles are preferred, but would an AL 80 suffice? I know newport divers insists on a pony bottle as well...

I personally think an AL80 with a pony bottle of sufficient size is fine for this wreck. You will reach NDL's long before you come close to depleting an AL80 unless you have a super high air consumption rate (SAC rate). You and your buddy should both be equipped with a pony bottle of sufficient volume to allow you to surface with a safety stop in the event of a OOG situation. An NDL dive on this wreck will be reached in 10-12 minutes from splash depending upon your descent rate and this assumes you are maintaining an average depth of 118' (top of the hull). If you descend straight to the bottom at 125' your NDL time will be 7-9 minutes depending upon your descent rate.

--Matt

 

[Soggy]

As usual, Matt and I disagree on dive planning.