Tow Sled Best Option?

[DivingFirefighter]

Hello everyone! So I've been active with the local marine rescue team. The other day we had a call out to search for a Kayaker who had been hit by a boat. We had a hard wind out of the north with fairly rough water on a sizable lake (32 mi long 3 mi widest point). Of course our search area wasn't THAT big. The team leader made the decision to use a tow sled operation, in this area there are very few unique features to use for reference. IMO we would have been better off to spend more time sorting out the area to search and maybe used a simple jack stay pattern, we had approx. or 10' of viz. We ended up failing to locate the victim, however the sheriff's department ended up locating the victim south and east of our search area. Any one have any comments on tow sleds and the appropriate use of them?

Thanks!

 

[Wildbill]

I've only used them a couple of times during training. The viz in my area is not that great so it's not likely we would be using it for a search. I can see where it would be beneficial to teams that work in clearer waters.

 

[ditch-diver]

We use them a lot. In some places I've been we probably sled 75-80% of the time. With some viz and a large search area and no drop sonar available, it is a very effective way to clear an area. Always two divers, either on a double sled or singles in site of each other. Through water comms and bob's your uncle. If no features around, we always set buoys as a pattern and/or use a gps set to tracking to show your coverage.

 

[DivingFirefighter]

We use them a lot. In some places I've been we probably sled 75-80% of the time. With some viz and a large search area and no drop sonar available, it is a very effective way to clear an area. Always two divers, either on a double sled or singles in site of each other. Through water comms and bob's your uncle. If no features around, we always set buoys as a pattern and/or use a gps set to tracking to show your coverage.

We did use marker bouys but in the conditions they weren't exactly great markers. And we don't have comms so we have rely on line signals, but while under power thats not an option. When we are out of air we just let go of the sled and surface, but that seams like it could really screw up the pattern. How do you go about making turns? We stop, the boat pulls in the slack makes there turn and starts back. What kind of pattern(s) do you use?

Thanks

 

[ditch-diver]

How big is the boat? We sled with through-water comms but with boats 15' and under we have no problem relaying line signals up the line.

Depending on how tight the boat can turn, we either go back and forth like plowing a field or if the boat needs more room we run a pattern like a zamboni cleaning the ice(Sorry for the Canadianism) .

We know based on or pattern if we'll be turning to port or starboard, the boat turns without pulling in the line, we turn ourselves in the water and watch as our line bends as the line goes by, then it tightens and we are away. We tell our guys to monitor their pressures on the passes and end on a turn. That way we are at one end or the other. We wait for the boat to go by (to get rid of the issue of getting run over) and as soon as it straightens we come off and come up. We tell the guys in the briefing that even if they still have lots of air but not enough to complete a pass, do not start it. It should help with those gaps you were concerned about

 

[MonkeyBiz]

Not sure what you mean when you say that you used a tow-sled. I signed up for a safety team spot this past weekend for a triathlon. We had our Jet Ski with our sled, that is towed behind it. Worked well when we pull an exhausted swimmer out of the water, and brought him back to shore.

 

[ditch-diver]

A sled for diving is towed behind a boat, usually with a minimum 3 to 1 scope on the line (100' of rope out for a 30' depth). It allows the divers to be on the bottom (just above it actually) while the boat clears the area in a set pattern

 

[MonkeyBiz]

Ahhh. Gotcha

 

[BladesRobinson]

There are 10 attributes to a search pattern and one of them is that the search must start at a known point, stop at a known point and cover a known area. Another attribute is that the pattern allows for communication between the diver(s) and top side personnel.

When a diver looses contact with personnel on the surface or with his dive partners, the Grim Reaper is likely to strike and take the life of a teammate, husband, father, friend, etc.

Ron Siver was a PSD killed in 1984 during a sled operation (out of air and a "J" valve were contributing factors). Donald Shultz was a PSD (May 2004), Mark Miller (March 2004), Paul Jolliff (June 2002), J. C. Smith (June 2000), Bryan Pottberg (1999) were all PSD line of duty deaths where a lack of communications was a common denominator cited by investigators.

The NFPA understands that a lack of communications between divers and top side personnel are necessary in assuring diver safety and that is why a means of "electronic communications" is a requirement for public safety divers.

While underwater sleds have proven themselves to be helpful tools in some ideal conditions, the conditions "DivingFirefighter" describes sound less than ideal.

Certainly this dive operation was not within the guidelines established by the NFPA and I am optimistic that many teams may have done things differently. While I do not like to second guess the decision made by a team leader, I would privately like to discuss how things could have been done to assure diver safety and with a higher degree of success.

Diving with a poor last seen point is a bad scenario but having a line of duty death and planning a departmental funeral is far worse, especially when a "risk/benefit factor" is considered (a recovery dive).

Inexpensive SONAR systems have proven to be an effective tool. If a team cannot purchase one, they should work to learn who in their region owns one. In this case, and without the benefit of knowing all of the facts, I think I would have called for a SONAR before deploying divers without comms, in limited vis, on sleds.

The IADRS has helped several teams acquire grant money for SONAR systems and if you need some help, consider visiting: http://www.diverescueintl.com/Events_and_Grants.aspx

Fraternally,

Blades Robinson