Snatching Moorings

[chappers]

I have a 3.5tonne motorboat moored in a trot that dries out in an estuary. On spring tides there can be up to 3-4 knots of flood, the boats lifts and surges forward until the moorings snatch with some force. This worried me so i fitted a car tyre in the chain to act as a spring which helped but im not sure its the best solution. Any ideas would be greatly appreciated.

 

[Searush]

Shallow water, wind over tide creates steep waves. IMHO the best solution is a longer, heavier riser - if you have the swinging room. Or possibly use a heavy "angel" at the half-tide depth on the riser. This would take some of the sting out of the snatch as the force to straighten out the riser will slow down the boats acceleration on th ewaves. What do the other boats do?

 

[samwise]

Not sure if one of those coil spring shock absorbers would work so well on a trot mooring, but they certainly worked for us in a Spanish marina berth afflicted by nasty surges when the wind was in a certain quarter. Maybe worth a try. We also tried the rubber ones which were pretty useless and fractured in next to no time.

 

[philip_stevens]

Many years ago, when Breton crabbers used to fish off Cornwall, if one had serious engine trouble, the tow home was with chains (not warps) with a tyre taking up the snatch. There was always a chain loop between the two chains of each side of the tyre.

So your tyre anti-snatch device has been in use for quite a while. A good re-use of an old method.