Sunday Nov 23 Bennett Springs; wanna go?

[wb5plj]

Does any one want to Dive Bennett Springs on Sunday Nov 23?

Had a small group of people but some have dropped out.

Bennett Springs is near Lebanon MO, it is a spring so it is a bit on the cold side. and really just a large cavern (I do not suggest penetrating into the cave, unless you are trained and have the gear) it should be considered a night dive and bring a lite but the water is very clear and there are tuns of trout.

There are some restrictions, there must be four divers minimum and six divers maximum and only four divers in the water at any time. Hey I don't make em'. There are two of us and we need two more and up to four more.

You do not need to be a cave diver, or cavern diver, the area is clean of protrusions so there is nothing to get snagged on and the water flow keeps it free of sediment so it is all but impossible to stir up the bottom and loose the visibility. It is essentially a strait shaft that heads down at about 40% for probably 100' or so, the max depth right up at the restriction into the cave portion is 100' deep but you really have to work to get there. There is no fear of accidentally entering the cave portion, you have to work hard to make it through that restriction due to the current. but just a few feet away you will not notice the current at all due to the cavern portion opening up widely, Any open water diver with more than a couple of colder dives can make this dive. I will likely dive it dry but this will be my first time for that. I have dove it several times wet as late as late early December. Typically I am not that tolerant of the cold but then again I like diving so there you have it.

This is really a good dive if you can brave the cold. they only allow diving after the fishing season is over and on Nov 1 for a cleanup dive (at which time the restrictions on diving rules are suspended) A group of us are planing on going down on Nov 1 for the cleanup (come on down) but we also had this date. Since all but two have had to back out due to other issues I figured I would see if anyone else wanted to go before I gave up the date. When I first started going down here almost no one was going so the dates where all open in Nov but it is getting popular and this year the dates where booked right off the bat. If I don't here from someone in a few days I will relinquish the date so others might go.

When you dive you have to continue along Hwy 64A to the park office, it is just on your right before you cross over the bridge. they can direct you to the spring after you show your c-card and sign the form. There is no fee and no services for divers so you will need all of your own gear.

the address of the office is
26250 Hwy 64A
Lebanon, MO 65536-6797
417-532-4338

The State park page (though not very focused on SCUBA, strangely they think it is good for fishing)

Bennett Spring State Park - Missouri State Parks and Historic Sites, MoDNR

here is a link of a satellite image.

Missouri State Park loc: Lebanon, MO - Google Maps

the image is not that good but it can be used to get there if you are not familiar.

 

[Wkndbum]

PM sent

Terry

 

[diverbob]

I had head this is a good place for cavern training. I had no idea there was a cave there. Any other details on the cave?

 

[wb5plj]

I had head this is a good place for cavern training. I had no idea there was a cave there. Any other details on the cave?

yea the cave is interesting. I have done penetrations into the cave portion. Last year was a little easier as the primary restriction at the bottom of the cavern has broken open a bit, it is not that you couldn't fit before but that this will slow the water flow trying to come out while you are going in.

two years ago the entrance to the cave portion was a very small restriction down at the very bottom of the cavern and was very difficult to get into. it was that the water was trying really hard to get out. you had to test your aproach well and come down on the restriction from above, not that there was a lot of "above". You could not rely on brute force to swim your self through, you had to come down fast! from above and get your hands and elbows through the restriction and kick like mad to give you just enough to get through to your belly. But don't stop at that point or the flow would flush you right out again. get you hands turned around and try and pull, push, worm, struggle your way out of the primary flow. then you where in.

There was a huge amount of danger in doing this. Many of the divers with us could not manage to get them selves in. getting flushed out the restriction was dangerous as you could easily snag gear and tear it up. mind you you are at 100' so you are going to need that gear for a while. You could easily loose a mask to the flow (you have a backup right) or at least expect it to get knocked loose and flood and while you are in the hard current your regulator will be free flowing from the pressure on the diaphragm. closing down the adjustable barrel poppet second stage did not help at all. So if you take just a second longer than you should you will be way low on air. the final problem was the wall you are trying to get on the other side of. if you got just on the other side of the was but where flat against it and didn't have a lot of upper body strength you can easily get pined to the wall. think of doing a push up with a lot of people on your back.

There was this female diver that went in once and she had basically open water gear. She managed to just get herself on the other side of the restriction (I am impressed, she was in wetsuit and the smaller tank and gear configuration helped but it still speaks to her tanisity). but she burned a tun of air trying to do it and further once she got on the other side she got pined to the wall. she had one of those aqualung safe seconds that is flat round and bright yellow and conveniently she was pined ontop of it so both regulators are free flowing. She didn't have the upper body strength to just push herself off. not to mention that just after you get through all you want to do is sit there and pant for a while like the hound that missed the rabbit. Another very strong diver (strong swimer) saw her going in and started making for her from about 25' away. he got to the restriction just after she got pined and realized she was in big trouble. he managed to reach through and grab her valve on her tank and through adrinlian and a bit of panic just ripped her back into the stream which flushed them back through to the cavern side. He drug her to the side of the cavern (they where about 90' at this point) and she had something like 100psi of air. Not sure the exact amount but it was surprisingly little. My point is that it goes fast.

once you get in (now or then) you are in a fairly wide chamber maybe 30' or more that has about 5' height. There are several columns every ware you look (Be very careful because a collection of columns can really confuse you when your start your return or look back) it is very clear and there is almost no concern with mucking the visibility. the floor is covered with the same pebble rocks (river rocks) that you saw out in the cavern but in this environment many of them are flying. the current is constantly picking them up and throwing them around, it is not so much that it is disorienting but it can be distracting. the low cealing height is welcome. you can brace your head against the cealing and put your feet in the rocks and you have a few seconds to rest against the current. but don't drop your guard as the rocks will erode out from under your feet much like beach sand with the waves.

There has been some one back in there before that left a line (rope) and even has it attached to a mooring block that was put down there. I am pretty sure that re-bar is not a naturally occurring growth inside MO Springs. Speaking of growth this cave has a strong enough current that their are no delicate formations or the like so you can be more comfortable about putting your head in the cealing etc... you shouldn't be killing off or destroying anything.

When I went back in we had to turn after about 100 yards into the cave (I am guessing and guessing distance in a foreign environment is not something I am the best at) we where planing on marking our real but we had problems with the real. this is not the typical sedate cave dive so if your real gets any slack line in it then the current will whip the thing around quite aggressively and in moments the diver running the real was all snagged up, the real completely rat-nested. and I had to spend a few minuets just getting the loose like unwrapped from him. then we had to turn the dive because I spend to much air getting through the restriction.

I was diving this one Wet and the guy I was diving with was in a dry suit. on the way out the flow as we where carefully trying to get back out without getting pined actually pushed his neck seal down and flipped it over as he was bracing himself (head against the cealing) with his back to the flow waiting for me to make my run at the primary restriction. You do (or did) have to be careful coming back out as the flow will zip you along quite quick and a hit to the head would do you in, I could see how someone hitting wrong in that current could perhaps separate a shoulder etc... so, one at a time and be careful. By the time we got through the primary restriction and on to the other side. we picked up our stashed bottles and moved up to decompression stop outside the cavern. by the time we got out the diver with me had his suit full of water, I don't mean it leaked I mean he looked like the stay puff marshmallow man here coming out of the water. He was very very cold in decompression

Different years also can see greatly different flow rates from what the rangers tell me so it may be that there are years or times of the year where the flow is a bit lower and I can see how that would greatly ease the entry and exploration. The ranger had told us that the flow was very strong on the time I described above but then again all is relative.

You can see how it would be hard to "accidentally" enter the cave portion. I enjoyed it greatly and would and likely will do it again but please if anyone reading this is going to try, be careful and learn how to do it well. cave diving has it's concerns and high flow years in springs complicate that greatly, that being said it is very worth doing and can be done safely enough.


I am going to cancel the reservation that I have for Nov 23 as we don't have enough divers. so if someone has a group that wants it go for it.

 

[beperkins]

I would like to join you if you are still going, I live in Lebanon so it is very close to me. I am planning on being down there on Nov. 1st for the cleanup dive so we could get together and talk about it. I can probably scare up 1 more buddy too, to get the total up if you need it. I have the spring reserved for Nov 15th and can only muster 1 or 2 people so if you or anyone in your group would like to go, let me know.
Let me know,
Ben

 

[wb5plj]

Afraid not. I have already relinquished the date.

 

[beperkins]

Interested in going the 15th?

 

[wb5plj]

well I am actually going on the16 (weather permitting) so I am out on that. thanks for the offer.

We did the cavern on after the cleanup dive yesterday. I must say that the flow was the strongest I have seen it. and the topography of the cavern has changed quite a bit. the floor changes shape quite a bit from time to time. the primary restriction seams to be completely gone. pushing a swell up in the flore at about 70' deep. when we where there the visibility was very bad for this site. but the good thing is that it continually changes and will likely get better.