Usually I just do a lot of reading on the boards but maybe I can contribute something to this disscussion. I am a public safety diver as well as a search dog handler. My dog is not an HRD dog but I do work with other handlers on my team that do have land and water human remains detector dogs.
I agree with what Gary has said, keep the dogs in the toolbox but realize they are not the end all be all for locating victims. That being said they can be very effective and if the dogs are solid-well trained dogs they can make your life much easier.
One thing that has not yet come up in this thread is certification. The search dog world is not unlike public saftey diving. There are more than a few search dog organizations that have no credentials. They do some minor training, put their shingle out, and respond to searches. It would be like a diver finishing basic open water then responding to emergenices. I reccomend that you get to know the K9 teams in your area before an actual search call. Do some training and learn their stregnths and weaknesses.
To give you an idea how my team operates: We do not come to a search to take over operations or tell IC what to do. We are a resource and we would never raise a stink or tell anyone when or where to dive. Ideally we will take a single dog out on a boat and do a grid using the wind and current to our advantage. We use GPS and triangulation with landmarks to mark hits where the K9 indicates(we leave no buoys or markers yet so the second dog does not have visual cues). We will then take a second dog out and work them the same way (the second handler does not know if or where the first dog indicated, they stay out of sight while the first dog was out). We then use the information the dogs gave us and look at wind,current, time since the person was last seen, depth all into account and give IC an area we think the vicitm is. Alerts should be checked with a second dog or side scan sonar if possible. We also have trained handlers on shore with binoculars watching the dogs, sometimes the dogs body language can be missed by a handler in the boat right next to him (for example changes in his tail might be out of the handlers sight if they are right up by his head.)
I will also add that distractions need to be minimized. Dogs can be distracted by activity on the shore so press, bystanders and other responders should be removed from the immediate area if possible. Also I would ask that dive operations be stopped while the dogs are out as that might cause false alerts as well.
As far as the OP's question: I would not hesitate to use a dog within 24 hours of a drowning. The water temp and the dry suit would certainly add a degree of difficulty but I dont think that should rule out the possibility of an indication. And as far as giving a specific answer on how long until a dog should make a find I don't think thats possible, it is kind of like the how long until a body floats question. There are a lot of variables involved. That being said; I have been involved in successful searches with dogs as early as 8 hours after the drowning. In fact waiting too long could make things difficult as well. If you are searching a smaller or stagnant area I imagine its possible for the area to get saturated with scent and have the dog give indications in areas away from the body.
I am not the HRD guru by any means, I just hate to think that police and fire have a bad taste in their mouth because of one or two bad experiences. It is possible conditions made success impossible on that day, or its possible the team they worked with over stated thier actual skill. There are good dogs out there, try to find them now not on the day of a search.
sorry for the long post...dogs are just a passion of mine and when I get going I cant shut up sometimes.
-Adam
