Fore & Aft Moorings

[stretch33]

I have the chance of a very cheap mooring, its a drying spot in soft mud and should give me 2.5 hours either side of the tide but l will have to lay my own tackle, The really soft stuff is about 4' deep. (same as my draft)
l have access to some good heavy weights and chain. What l need to know is whats the best distance to lay the fore & aft weights apart? My boat is 33'/6 tons The locals reckon to put the two weights down with about 4 foot of chain attached to it thence rope upto the mooring buoys. Any advice would be welcomed.
Cheers in advance

 

[yoda]

Having already seen one boat break it's mooring this season I would recomend chain all the way to the cleat. With a fore and aft mooring you may also be held against the prevailing wind which could exert large forces. 2 tons of concrete with 4 inch long link chain for the first few feet, swivel, then smaller chain to your buoys. swivel above the bouy to your mooring chain (nice new galvanized stuff with plastic tube to prevent chaff). May seem over the top but better than breaking free.

 

[brian_neale]

Back when I had a swinging mooring, there was heavy chain from sinker to buoy, then lighter chain plus separate rope bridle to mooring cleat. The boat rode to the rope (sleeved with pipe through the stemhead fitting) but would lie to the chain if the rope broke. Attach the chain and rope with separate shackles to the riser chain, wire every shackle, and do not mix stainless shackles or hard eyes with galvanised chain anywhere underwater. Use galvanised throughout - it lasts longer!

 

[Trevor_swfyc]

Not a great lover of fore & Aft Moorings, all our mooring are free swinging. If the stern mooring line gets caught on the rudder goodbye rudder. Also as mooring is tidal strong forces can develop with wind and tide from the stern anyway thats bye & bye if you must have Fore & Aft so be it.
The best way is to make a scale drawing enter the details you know ie boat length, height at high tide. The angle of buoy to sinker does not want to exceed 45 degrees at high tide draw this in now measure off the desired distance between the sinkers.
Use part chain part rope the use of chain will give the mooring shock absorbing ability. I would find the max spring tide actual on the mooring and use this length in chain the rest rope and obviously you will require some slack / free play.
Sinkers we use car tyres 205 x 14 full of concrete with 1 metre of 1" chain or heavier if available attached to the concrete, buried about 2ft in mud never known one pull out.
If you want info on swinging moorings thats more my thing then please come back to me.
Note look at other boats moorings in the same area for more usefull info.
All the best
Trevor
Moorings Officer SWFYC

 

[LadyInBed]

Is this a coastal (exposed) site or on a river /in a sheltered estuary?
If the former then swinging is much better than Fore and Aft.
If the latter and if you get any choice in the matter, then try and lay in line with prevailing wind (SW-NE?)
If you use tyre and concrete run a shackled loop of heavy chain round the inside of the tyre before concrete.
I would use at least 6-8ft of long link ground chain (that’s free chain after any around the tyre) then 1½ x max depth of water for riser on a swinging mooring.
For a Fore and Aft this can be reduced considerably but lay the ground tackle far enough apart so that when you tie your boat between the buoys and tighten up the lines (you don’t need chain mooring lines if on a river), you have about 4ft between each end of the boat and the buoy.
I am on a Fore and Aft on a river, and always tie two bow and two stern lines. This stops too much sideways movement in cross winds.

 

[pete]

After 6 years on a swinging mooring last season I changed it to fore and aft the main problem we had was that being twin keel when tide came in (behind boat) it skidded forward and sideways over the riser if the keel caught on the chain the boat was held sideways to the incoming tide aprox 3-4 knots and was quite dramatic the boat would heel well over and the presure was incredible until at high water when it usually freed itself even with the chain and strops protected with pipe they still managed to scrape the boat a few times now I have double security, boat always faces incoming tide and prevailing wind and lifts very gently . I made a scale model of boat in ply with a piece of ply as the sea bed and rigged string between the two in relation to the highest spring tide and there was no way I could get it to wrap round the rudder as this was my greatest fear. Recomend you keep lines reasonably steep (mine weights are about 35 ft apart for a 27ft boat) and risers as short as possible allowing a little for exceptional tides.

good luck

Pete

 

[Guest]

I used fore and aft moorings in the Bristol Channel with a 13 metre yes (13 Metre))tidal rise although on the mooring it was probably about 7 metres. We used chain risers from across the pill (river inlet) mooring also in chain. It was important to have some large mooring buoys with sufficient buoyancy to support the chain risers,and we had double bow and stern rope mooring lines from the buoys connected with a courtesy line.Never had any problems with this mooring as you did not have to lift the whole weight of the mooring as the buoys did the work for you.