To help the swimmer, why don't let him float with an inter-tube. Then he use both hands to steady the rod instead of trying to do that and tread water at the same time. If he's not already doing so, get him some swim-fins. It would make dealing with currents a whole lot easier and less tiresome.
I have no ideas, but would love it if you shot some video the next time you are out and post it here or a link to YouTube. I have been in some crazy and nasty places surveying, but this is a new one to me.
> I have no ideas, but would love it if you shot some video the next time you are out and post it here or a link to YouTube. I have been in some crazy and nasty places surveying, but this is a new one to me.
I'll second that!
:hi5: :stakeout: :hi5:
its not the easiest but what I do is send a swimmer out with a 25' rod and we use a topcon 360 prism on top and a 9003 robot but we keep the radio and data collector at the gun, we just get the gun close and it autlocks and we take the shot..anything over 6 feet depth you can use a small boat and the 25 foot rod with 2 men (or you can use a depth sounder) personally, if i did any more than 2 or three jobs like these a year, the boat/depth sounder and right software would be a necessity.
41°39'37.74"N
70° 3'51.47"W
I have a drill hole here. Ran a topo of the flats to the west many years ago. Hired a buddy who surfs to run the rod. No real surf here. Stadia rod and total station used like a transit.
hello mbuck,
why not consider a second-hand robotic unit. it will track your man all day long and modern ones are better at not getting distracted by bright reflections.
the leica 1200 units we use have a mode specifically designed for accurately tracking and measuring moving prisms. in the 'SynchroTrack' mode the unit will perform a linear interpolation between angular measurements either side of the distance measurement to coincide with the timestamp of said measurement.
> My concern with the reflector-less prism is that the beach is short with a steep foreshore and as a result background behind the prism tends to water and not horizon, and I would be concerned about false returns off the ocean surface behind it (anyone have real world experience with this?). We can make the rod taller, but then it becomes more unstable and difficult for a swimmer to hold steady in the surf when there is a strong longshore current.
>
> foggyidea - small boat not feasible in this surf though we have thought about it. Thanks for the leica recomendation....someone else recomended them to me for this application and I will look into it.
Hello, try this 🙂
Range of this RC boat is around 500 meters, attach a GPS or 360 deg prism on top and a bluetooth depthsounder at bottom. Approximate costs are; 3000-4000 USD for RC Boat, 4500 for Sonarmite ecosounder and 200-300 USD for the prism.
Between the winds, waves, and currents the swimmer will be fighting to keep in the inner tube steady as well as the rod.
A robotic unit with tracking would be great but out of our price range. I will check out the bear 360 prisms but wonder if it will be any better than the leica. We take less than 50 shots a day so I don't see how logging these shots really makes it that much more efficient. The topo portion of the survey is already performed with RTK GPS.
Haha thats great! That would be so much fun to use, but it would get wrecked in the surf.
Ok I'll try to get some pics/video the next time I'm out. We usually roll as a two man crew so its hard to get the action shots.
Maybe I should consider a longer rod, though the longer it gets the more difficult it is for the swimmer to use. We use about a 15ft rod at the moment and maybe just a few more feet would help without sacrificing too much in stability. We have considered the boat, but with the steep beach and rough surf I still see issues with trying to keep the boat in one place to keep the rod steady (and keeping the boat off the beach!).
25' fiberglass rod and stadia sounds like it would be close enough. we did a similar shoot on Lake Havasu years ago to topo for a new boat ramp, altho the surf wasn't an issue on the lake.
Here is an idea, from a buddy of mine, who has done some of these. Maybe some of these ideas will help ~ Nate
"I need some input on selecting a total station for taking shots in the surf (we do other survey work as well but need a total that can perform well in this application). Currently my company monitors beach transects that start in the dunes and end in the surf at roughly -5 ft MLW. In order to get the last shot in the transect, we send out a swimmer with a rod who treads water while holding the rod(accuracy does not need to be pinpoint for this work)."
This guys not thinking out of the box and the solution is simple and a lot more safer for the swimmer.
Get a TALL guy to go out in the water..taller the better. The swimmer just has to know when he is in five feet of water..maybe like when the water surface is at his armpits or something like that. Prior to sending the guy out, get a construction safety helmet or something of the like and on top of that jury rig a couple of old reflectors..2 should be fine, maybe even one would do. Measure the IH of the swimmer from the ground to the reflector on the helmet..constant rod height.
The rest is simple. When the swimmer gets to +/- 5 feet in depth he faces the gun while using his arms to steady himself and the gunner gets the shot. No more rod to deal with..
(From Nate's old buddy)
I second wide beam EDM.
I have a Nikon 821 (not reflectorless) and that is very good at that application.
I have surveyed miles of rivers where at times I can't see the prism for leaves, only know it's location. I have high visibility cloth wrapped around top of pole.
The Nikon makes a buzz when it senses a signal and I then fine tune through scope. I search for the cloth and grab the shot that way.
I am always amazed how it reads what seems the impossible.
I doubted its ability once so did some tests where I'd read through the scrub then clean all obstacles.
Distances always the same. Don't question it now.
In past used an old Topcon Guppy for soundings. That was okay too.
Newer Nikons are not so good in finding targets in testing conditions , as told by my supplier.
Maybe so, Nate. I know from surf fishing and wading out to my armpits on the last sand bar, to cast, that with rough surf, there aren't very many time when you're feet are touching bottom. Every wave that comes along just kinda' floats you.
I got to thinking, if the "Surfer" had about 50 LBS of lead, weights, on a weight belt, it could stabilize him, enough to make the task easier. I guess it depends on how high the surf was that day.
N
The swimmer has enough trouble fighting the surf and current with the survey rod. Adding 50 lbs of lead to him will be equivalent to giving him cement shoes....
Nate - I appreciate your buddies input, but that will not work as the swimmer cannot touch bottom at any point during these swimming shots (I'm 6'2" and have never been able to touch when I have been the swimmer). Even if he could there is no way that he is standing with the surf bearing down on him. While we are supposed to survey to at least -5ft MLW (i.e. roughly -5ft NAVD), we end up going slightly deeper to be certain, and then when you add in surf and wave setup that usually means the water depth is 7-10ft deep. I appreciate you guys thinking outside of the box though.
