Drift dive in a river...

[Atom]

Anybody has tips for that?

Me and a friend are considering doing a drift dive in small river up here in Quebec (obviously there are no rapids in the section we want to dive). The setup we're considering is, bot of us drifting (in dry suits since I know from experience that the water is quite cold in that river at this time of the year) with a float (with flag) and 2 canoes with friends going along with us, matching speed with the float. The canoes would be used in case of problem and would pick us up when we run out of air / bottom time. We'd then proceed to the cabin which is further down the river.

I've done drift dives before but they were mostly in open ocean, not in a river so I'm wondering if anybody has some experience with that.

 

[skdiver.com]

sorry no tips but that does sound like alot of fun. Ive always wanted to dive a river but all we got is dirty south and north sask rivers around here

have fun with this

 

[DA Aquamaster]

If the current is really strong, stay a pound or so negative and keep your fin tips on the bottom if you need to be right on the bottom.

In a river with strong current (3-7 kts - strong enough to blow most of the silt leaving a sand, gravel or rock botttom) the current is usually a knot or two slower right on the bottom, so if you dive with your fins significantly higher, they will be in faster water and you will essentially go ass over tea kettle. Also, being slightly negative and dragging your fin tips on the bottom, lets you stop while facing downstream without having your fins pass the rest of you.

If you fly a bit higher off the bottom you can stay neutral and do the superman thing. Large rocks will have eddies behind them where you can stop if needed, and the current will flow around large rocks and take you with it, so you can miss them with minimal change in direction in a fast current.

Most larger or fast rivers will have a back wash of sorts closer to shore. In extreme cases and on the inside of a bend in a river, the current can actually move upstream. Also, the current tends to be faster around the outside a bend in a river. So if you need to move upstream, you want to be close to shore and/or on the inside of a bend in the river, while the fastest trip downstream will be in the middle of the river. Most people with any time on a river in a canoe have already figured that out.

If a canoe is following your flag on the surface while you are drifting on or near the bottom, they will periodically have to move upstream to keep from outpacing you and/or they will need to follwo closer to the side of the river where the current is a bit slower.

In a fast moving river with fairly clean headwaters, viz can be very good (30 plus ft) but a tributary dumping silt into it can reduce the viz to zero in very short order. In low viz and fast current it is easy to drift into a tree or other type of snag, so you want to have cutting tools handy. It may make more sense for the canoe to carry the flag and follow your bubbles, to reduce the entanglement hazard.

If you are diving as a buddy team, be aware that if one of you stops or turns to look at something the other needs to react immediately or a separation will occur. Know your plan for separation as it will happen. In some low viz situations you may want to trade the lead position with the understanding that the leader conducts the dive, and the buddy just concentrates on staying with the leader.

 

[sschlesi]

I've never dove in a river, but I have travelled and swam in several rivers in the interior of BC. My biggest concern would probably be avoiding trees that are in the river. Particularly during the spring melt, many rivers will have many downed trees in them, getting pressed into the branches by a strong current would be extremely dangerous. Of course some rivers are much less prone to that problem. Regardless, I'd want to be familiar with the river topside before conducting the dive.

 

[odinsfrigg]

Our check out dives were in a spring fed river, after demonstrating our skills we did a drift dive with one canoe that held the dive flag and extra tanks, but the water was 72 so wearing a suit was optional.

 

[Polar_diver]

If you are thinking of the Richelieu river you should wait a little. As most of other rivers up here, water are as clear as chocolate milk at that time of the year. Viz is not even an arm lenght! I almost broke my nose two year ago as I hit a large rock I just couldn't see!!!

 

[don Francisco]

You seem to have covered the bases, and assuming viz is decent could have a nice dive.

One caveat - if the current is fairly fast, make sure your canoe team is briefed on how to manage in a current. Since the current is fastest mid stream at the surface and slower near the bottom, or along the shores, odds are the canoes will drift faster than you. They need to plan to move off towards shore to avoid wearing themselves out paddling upstream trying to match your slower drift rate.

Likewise if there's any wind. The canoe may have to fight it, whereas you'll be unaffected. Following a dive flag is easy with a motor, less so under human power.

Lastly, try to explore some "plan B" shore exit options, just in case the canoe is carried downstream of you in the current before you surface.

 

[Doc Harry]

I dive in whitewater rivers here in West Virginia - obviously I choose my poison carefully.

There are three major problems with diving in a river:

1. SEIVES
2. RAPIDS
3. MAN-MADE OBSTACLES

1. A seive is a collection of rocks or logs that acts like a strainer. Water can pass through but larger objects (like people) get trapped. If the current is strong, then the danger from seives is very high. If you get thrown into a seive, the current may hold you in place and prevent you from escaping.

If the visibility is poor and you are moving fast in the current, the danger from seives is astronomically high. It's like driving 140 mph at night - your headlights do not see far enough in the distance for you to react quickly enough to avoid obstacles. Underwater, you could get stuffed under some boulders and wedged in placed before you even saw the boulder coming at you.

2. The second danger is whitewater rapids. If there are rapids, you've got to get out of the water before you get washed into the rapid.

3. Man-made obstacles are always more dangerous than natural obstacles. Things like rebar and collapsed bridges, cars, etc., are all serious hazards. Tread carefully.

If the current is moving slowly and the visibility is good, then river diving is much more enjoyable and safer.

 

[Dan Weidert]

I agree with Doc. I have snorkled in rivers and used tanks in shallow stretches where I walked up stream first to make sure there were no obstacles in my way. If the current is slow enough, it is like flying (only better ).

However, it is extremely easy to grossly underestimate the power of moving water. Rocks and trees make great objects to be pinned against for a long, long time.

Dan

 

[H2Andy]

basically confirming what people have already said

separation in a river drift is a real concern, particularly if the visibility is low. you need to stick together like glue. might think of using a buddy line but that leads to:

beware of possible entanglements. there might be logs and other debris scattered about which could really ruin your day if you have a buddy line

and of course, if the current is too fast, it can pin you against obstacles or make it impossible for you to reach your buddy if they get in trouble up-current from you

there are two rivers here in Florida that i drift dive often, the Santa Fe and Rainbow River

the Santa Fe can have visibility problems, so staying up with your buddy is key. the Rainbow River is so clear you don't have that problem. both have a very reasonable current, but even so, swimming against the current can exhaust you very quickly