sparky30
Contributor
advtech:Getting older, memory poor. It's been a couple of years since I did the math and I pulled the figures from memory. I thought I better check them and clarify.
Concrete is about 150# per cubic ft. Our smallest blocks are 2x2x4 for 2400#. Concrete only weighs 56% of it's weight in water so are small blocks are 1200#. We count on the suction from Lake Erie's muck for an additional 50% minimum for 1800#. In many cases the blocks are totally submerged into the bottom which will give us more. Our larger Lake Erie blocks are 3200#. It was a matter of what we could buy and get delivered cheap. Most we had made with a stainless steel bar instead of the normal rebar.
Because we couldn't count on bottom suction for the Tiller Wreck, we wanted a minimum of 3600#. A single block would have pushed the limits of the boat and crane we had available so we went with 3 smaller blocks.
We keep getting asked, How big of boat does it take to drag the blocks off position and the answer is very small. In short, if you boat can hold 1800# without sinking, it can drag the anchors. Tieing up tight in rough conditions can pop and move the blocks.
This is avoided by useing scope in the line. Most of the other groups doing moorings use 25 to 50% (125 to 150 ft of line for 100' depth) but we have been unable to do this. Oue lines come up to 10' below the surface and then we use 25' of chain to the buoy which only gives us 15' of scope. (we also have a 25' long surface tag line which helps a little). If we didn't do it this way, all are buoys would dissapear every time there was a local fishing derby. As it is now, they would have to swim down a least 10' to cut the line or carry a good pair of bolt cutters. Please add lots of scope when useing our moorings.
Thanks for all the info.. I try not to be out on the lake when things get bumpy and I promise not to pop the moorings..
To be honest, this was very informative. I never really payd much attention to what's below.. Out of sight, out of mind so to speak..
I'm glad that you are using chain scope.. I'm all too familar with misc. floating items after a fishing derby.. Came accross a few 6x6 floats last year.. they float just at the surface.. They don't do much to a steel hulkl, but they'll go through fiberglass like butter..
Have there been many incidenced of people removing markers? Here or elsewhere? That could get expensive (not to mention annoying) very fast..