On Monday, 30 May 2022 at 09:38:16 UTC+1, Leon Warrington wrote:
Hi all,
Just wondering whether anyone had some thoughts about buoying lakes for regatta courses?
To provide context, we buoy our lake (Trentham Gardens , United Kingdom) every year for a 3 lane regatta. (so four lanes of buoys. Lake depth varies from about 1 - 2.5m along the length of the course.
At the moment we currently buoy using a system where we use individual buoys that are manually placed at appropriate intervals. We use a theodolite that is set up at one end of the lake, and then use radios to to let the buoying team know where is the appropriate point to drop the buoy.
We measures out lane widths using stakes that we drive into the lake at the start and finish.
Whilst this works well and produces straight lines of buoys, it is very time consuming (normally takes a team of 3 people about 3 days, longer if we make a mistake in lane widths!), the complicating factor is that the buoys can only go in a few days before the regatta and come out again a few days after.
We have tried to use a buoys on string system in the past, but were unable to anchor them sufficiently well to get the tension to keep a straight line.
I'm keen to get a simpler system. Does anyone have any alternative approaches / ideas? The trick in my mind is going to be providing sufficient anchoring systems for any kind of buoys on wire system. Ideally something that can be done once so all we need to do is hook the buoys on each year, but also sufficiently far below the water surface (>1m) to allow for coaching launches etc to pas over without damage when buoys are not in place.
Regards,
Leon.
Leon
My club uses a system based on a heavy (5 mm?) stainless steel cable. One end is anchored with a really heavy weight . The cable is mounted on a reel, carried on a barge or a floating platform (we often use a section of pontoon). There is a shackle at each position where we want a buoy. As the barge moves down the river we clip the riser cable to the main cable, and buoys to the riser cables with clothes pegs (so that the buoys release if struck). Once we get to the end of the course we put tension on the cable to get a straight line, then drop a second heavy weight.
This works fairly well, but we only use it over a 500 metre course, laying in about 3 to 4 metres water depth. It does depend on heavy anchors, which are scary to handle, so a safe working platform is important. We use as our main weight heavy chain in a large bucket that must weigh about 100 kg. This means when we retrieve we aren't trying to lift all the weight at once, as we can pull in sections of chain, but the weight allows us to put the cable under a fair amount of tension without dragging. Though the placing and tension of the line is what gets the line 90% in the right place, the line can be fine tuned by lifting and repositioning the cable, as it is the cable weight, rather than line tension that is the main factor in keeping it positioned. If a buoy is knocked off its riser we just lift the cable from an adjacent riser and pick up the cable to reattach.
It takes 2 people well under an hour to lay one 500 metre line, although that's after a lot of prep work, checking cables, untangling risers etc. I would think the system would still be viable out to 750 metres - the limit in part being the weight of cable reels - ours is at the limit for 2 people to maneuver. on and off the platform.
Andy M
--- SBBSecho 3.06-Win32
* Origin: SportNet Gateway Site (24:150/2)