Floating Moorings - Litterally!

connel42

Has anybody come across this before?

We have a series of floating moorings on Blessington Lake.
Thay are various sizes depending on the size of boat moored to them.
They range in weight from 200 to 750 kilos.

During the heavy freeze earlier this year one of the 200 kilo moorings shifted about 300 yards out into deeper water.
We had to lift it and bring it back in to its proper place.
The process of lifting the mooring is difficult as they are very heavy but we managed it.
We (the mooring users) figured it was a one off and although hard to believe it appears that as the frozen lake thawed it broke into large chunks of ice and these dragged the mooring a certain distance and dropped it as they thawed more.
Anyway fast forward to this winter and the same thing happened except we have two moorings dragged approx 500 yards down the shallows.
It is hard to believe that floating ice would have the pulling force required to do this but there is no other explanation.
Its going to be a pain if we have to start recovering moorings at the start of each season.
The answer is of course to increase the weihgt but thats a lot of hassle for a lake boat.
ayway i just thought I would post this to see if anyone has any comments.

Bob_the_dog

I believe the floating moorings in Dun Laoighaire harbour are layed out in strings linked together with large/heavy chains and steel railway wheels placed every x metres for extra ballast.

Even with this, the still drag in a heavy swell. Ice has an amazing force contained in it when it starts to shift. Not sure what can be done bar lifting at the end of the season

Tabnabs

Funnily enough, I saw something similar on Deadliest Catch recently When the pot string got into the ice pack it shifted miles away.

There probably isn't a workable solution to this if the gear has to be handled by hand. It's either retrieve them when they shift or pull them up at the end of the season. It's probably fair to say the harsh(er) winters are here to stay.

fergal.b

It works like putting a flat sheet of paper down on a table and moving it slowly towards a heavy object and pushing it, It's not so much the thickness of the ice it's more the huge force that moving it.:)

alexlyons

Bob_the_dog wrote: »

I believe the floating moorings in Dun Laoighaire harbour are layed out in strings linked together with large/heavy chains and steel railway wheels placed every x metres for extra ballast.

Even with this, the still drag in a heavy swell. Ice has an amazing force contained in it when it starts to shift. Not sure what can be done bar lifting at the end of the season

in a line of about 12 moorings, there is a tram wheel (I think they're about 3 ton) every 6 bots, ie start middle and end.

That said, in the longer strings out be the east pier they aren't as frequent. Some moorings have individual weights on them, about 1.5 ton and can hold boats of about 6 ton or so.

the ground chain is pretty heavy, about 10kg (15kg is in my head but something is telling me it's to much)

in all my life I have never known the strings, or even individual moorings to drag in heavy swell.. The only thing that can happen is if the riser chain is too long, it can sink into the mud and the boat can sit to close to others, or the wall. Cutting the riser chain solves this.

The wight on the individual moorings sinks into the mud. In the first season they require a bit of adjustment as they can be prone to movement with the boats on them when they haven't sunk. Ideally you want to lay new mooring weights at the end of the season so they sink over the 6 months or so with no boats pulling them.

edit: in answer to the OP, it seems like the weights are too small for the boats, especially considering the circumstances around the ice. What sort of boats or moored to them? the weights may seem enough, but if you are having trouble with them drifting then best and almost only thing to do is increase the weight.