Tiller Wreck Presentation

[advtech]

For anyone in the St. Catharines niebourhood, the Niagara Divers' Association will be holding it's monthly meeting Tuesday June 1 at the St. Catharines Public Library (accross from city hall). It starts at 7:30 PM.

We will be having a video presentation on the discovery and survey and attempted identification of what has become know as the "Pt. Dalhousie Tiller Wreck."

All welcome. Free coffee and donuts. As always there will be a short club business meeting first followed by the presentation.

More information at http://www.vaxxine.com/nda/meetings.htm

 

[sparky30]

For anyone in the St. Catharines niebourhood, the Niagara Divers' Association will be holding it's monthly meeting Tuesday June 1 at the St. Catharines Public Library (accross from city hall). It starts at 7:30 PM.

We will be having a video presentation on the discovery and survey and attempted identification of what has become know as the "Pt. Dalhousie Tiller Wreck."

All welcome. Free coffee and donuts. As always there will be a short club business meeting first followed by the presentation.

More information at http://www.vaxxine.com/nda/meetings.htm

Thanks for the info

 

[Scuba_Steve]

Planning on seeing you there Ian. I have also e-mailed it to a few folks that would not otherwise see it posted here.

Steve

 

[starfish365]

sounds great Ian - thanks - we'll see you there. I've posted on LDS message board also.

 

[sparky30]

That was a very informative meeting... I never realized how much work you guys do around the area...
The presentation on the "Tiller" was awesome. What a difference the zebra mussels make...
Thank you for a very informative evening....


P.S. How heavy are the mooring blocks again? I seem to remember a range from 1200 lbs to 3200 lbs per block.. Is that right?

 

[Scuba_Steve]

I think he said 3 2400lb???? with an in water weight of about 1700-1800???

Or was that a total for all three? It's all just numbers to me, as I wouldn't know what it would take to hold a dingy in place.

 

[advtech]

Most of our Lake Erie moorings are 2400# with a couple of 3200#. The 2400# block only weighs 1800# in water. We count on the suction from Lake Erie's muddy bottom to help us out as it almost doubles the value. Boats still need to add scope, especially on rough days.

The Tiller wreck in Lake Ontario has 3 1200# anchors in a triangle coming up to a single ring. We wanted more weight due to the hard packed bottom but we were limited to what we could lift and sling over the side with the crane. Hense the 3 smaller ones. seems to be working.

 

[sparky30]

Most of our Lake Erie moorings are 2400# with a couple of 3200#. The 2400# block only weighs 1800# in water. We count on the suction from Lake Erie's muddy bottom to help us out as it almost doubles the value. Boats still need to add scope, especially on rough days.

The Tiller wreck in Lake Ontario has 3 1200# anchors in a triangle coming up to a single ring. We wanted more weight due to the hard packed bottom but we were limited to what we could lift and sling over the side with the crane. Hense the 3 smaller ones. seems to be working.

The only reason I asked was because I am making changes to my mast rigging and I was wondering if I may be able to help in the future... I don't know if I can hoist 1.5 tons, but its worth doing the calculations...

 

[sparky30]

I can carry 3200lbs easily enough.. there is loads of deck space.. the problem would be getting the blocks over the side and in the water.. but I have an idea already...
How big is an average mooring block? I am guessing 3ft x 3ft x 2ft..
The whole thing would have to be done is reasonably calm water...

 

[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.