chain preventor

[Seastoke]

so we are planning a trip to a harbour that has swing moorings ,and the recommend having a chain preventor ,what is one

 

[BruceK]

Is it in reference to minimising swing? i.e. it a tight mooring area mobo's will swing differently to yachts when you have wind and current not lined up? If so maybe it's in reference to a short chain. In these instances (different swings) some P-hulls resolve this with either a small drogue, or if in a tight mooring spot where a drogue can be a navigation hazard, with a short length of heavy chain attached to a line. The practice is to lay the chain out behind the boat so that it is all lying on the sea bed parallel to the boat. The line goes from the chain directly (vertically) up to a stern cleat (or if anchored to the bow cleat to prevent surfing to the wind). This method only really works in shallow water though and where as it may not stop a swing will dampen any oscillation so that when you do you are not battering your neighbour.

 

[Hurricane]

Is it in reference to minimising swing? i.e. it a tight mooring area mobo's will swing differently to yachts when you have wind and current not lined up? If so maybe it's in reference to a short chain. In these instances (different swings) some P-hulls resolve this with either a small drogue, or if in a tight mooring spot where a drogue can be a navigation hazard, with a short length of heavy chain attached to a line. The practice is to lay the chain out behind the boat so that it is all lying on the sea bed parallel to the boat. The line goes from the chain directly (vertically) up to a stern cleat (or if anchored to the bow cleat to prevent surfing to the wind). This method only really works in shallow water though and where as it may not stop a swing will dampen any oscillation so that when you do you are not battering your neighbour.

Thats a good idea.
Unlike most mobos of our size, we end up in shallower water along with the yachties.
You are correct, we swing very differently to yachties (I wonder if those are the correct words!!)
Something like a drogue or a chain might work for us.

 

[BruceK]

Because my cruising grounds have such a large tidal range I have yet to use a short chain in anger on my cruiser (albeit I keep one) but do have a drogue. As Roy will attest there is one spot in particular where we like to shelter where at low tide the swing moorings can become so close that contact with a neighboring boat would be inevitable in certain wind conditions. (We had a mad scramble one night trying to sort it all out). A drogue overcomes the wind as the tidal current is sufficiently strong and avoids the use of a kedge which could exacerbate the issue should the neighbour not follow suite and the tides / winds change. A drogue has little effect on swing unless there is sufficient current, is a godsend if there is at least a knt or two of current and has proved invaluable in some tight anchorages to ensure we always lie in accordance with yachts and other keeled vessels. In our estuary moorings there are also a number of yachts that use a drogue to prevent them from chaffing against the mooring boy. It's quite remarkable to see them when without a drogue and in breathless calm conditions actually surf against the 4knt current (like a waterskier going wide) and overtake their mooring

 

[jrudge]

Because my cruising grounds have such a large tidal range I have yet to use a short chain in anger on my cruiser (albeit I keep one) but do have a drogue. As Roy will attest there is one spot in particular where we like to shelter where at low tide the swing moorings can become so close that contact with a neighboring boat would be inevitable in certain wind conditions. (We had a mad scramble one night trying to sort it all out). A drogue overcomes the wind as the tidal current is sufficiently strong and avoids the use of a kedge which could exacerbate the issue should the neighbour not follow suite and the tides / winds change. A drogue has little effect on swing unless there is sufficient current, is a godsend if there is at least a knt or two of current and has proved invaluable in some tight anchorages to ensure we always lie in accordance with yachts and other keeled vessels. In our estuary moorings there are also a number of yachts that use a drogue to prevent them from chaffing against the mooring boy. It's quite remarkable to see them when without a drogue and in breathless calm conditions actually surf against the 4knt current (like a waterskier going wide) and overtake their mooring

Does the provider of the mooring not have an obligation to make sure they are sufficiently spaced so that with the correct size of boat on them they cannot hit! Given the punter has no choice ( unlike anchoring) they seem to be creating intentional chaos.

 

[BruceK]

to be honest the moorings mentioned above are not in use (let out) by the council and as such are treated as freely available and gratis by boats seeking shelter for short periods. We know their rating, they are usually ~25m apart and sit in a back eddy that keeps them in line but when you have low water, slack and certain wind conditions (gusts) they can be as close as 15m apart which means if one boat swings 180 degrees before the other which happens as the back eddy closes in to the small peninsula that causes it with the change in tidal current you are going to hit each other. I imagine it is for this reason they are not let out. One can hardly hold the owner (council) responsible for this.

 

[Hurricane]

Does the provider of the mooring not have an obligation to make sure they are sufficiently spaced so that with the correct size of boat on them they cannot hit! Given the punter has no choice ( unlike anchoring) they seem to be creating intentional chaos.

I thought the same last year.
We were on a buoy in Espalmador and were VERY close to other boats.
We didn't actually touch but I had to bring the tender in at one stage - we were that close.
Maybe I was worrying unnecessarily but I still wonder who is responsible.
BTW the buoys were managed well - and in the peak of the summer - very professional - much more professional that the people running San Antonio!!

EDIT
Just found this pic from Espalmador last year showing how close the buoys are:-