Strop Rigs for Swinging Mooring

[najsmith]

Ladies & Gents

I'm the proud owner of a swinging mooring and am trying to work out the best rig for my pickup bouy and mooring lines.

Currently The Riser chain is 1 & 3/4 inches up to the main bouy. There is a small bight of chain shackled to the riser and a small pickup bouy for pulling onboard and using over both fwd cleats, but its not long enough.

Have run this through the bow roller and it's acused the nut (acting as the pin for the roller) to undo and if I cadn't caught it in time would have wrecked the stemhead/bowroller footing.

My boats a trapper 500 (28ft) at 2 tonnes displacement (old money).

Want to take a more convensional approach, so was thinking, could I rig 2 rope strops, around 22mm? One to run through the bow roller & a hose section to minimise chafing, and the other a longer/ slack line I run through a fairlead?

The Bowrollers quite small - if you put the pin inm you're looking at a 25mm x 25mm apature to pull a rope through, so I guess two ropes would be too much for this.

I could also go for a rope & chain shackled seperately to the riser, but think it problematic running them over the same bow roller, given the dimentions.

Your help/advice would be most appreciated. Want to buy the appropriate bits ahead of avisit to the coast Sat Week.

 

[lw395]

I used to rely on one rope strop, 30 or 32mm 3 strand for a 7 ton boat.
To rely on rope, you have to eliminate chafe.
This required installing a new mooring cleat close to the stemhead, previously there was over 3ft of rope stretching back to the cleat, so enough movement to chafe wherever it touched, rub through polythene hoses etc.
At one point I had chain on deck to the cleat, but this was a little prone to snatching.
To avoid rust on your deck, stainless chain is cheaper now. Chain on the deck does not have to be so heavy as the corrosion is less, and inspection is easy. Do not rely on shackles lightly, I have had all sorts of mousing fail. Most reliable I found (short of welding!) is to replace pin with a bolt, then add lock washer, extra nut, copious loctite. Do it up using a socket set.
Having two strops simply didn't work, because my boat rotated on its mooring every tide. If one is going to fail, then the other will fail soon after if it has the same problems!
Whatever you do, and there is no one right answer, check it soon after installation for the slightest wear, would be my advice!
Take care,

 

[rob2]

It all depends on the hardware available on your foredeck. If I remember rightly there are two mooring cleats with associated fairleads on the Trapper 500? I agree wholeheartedly about fixing the bowroller to keep it together, but you could also fit twin nylon strops as long as possible from the lower swivel through each fairlead to the opposite cleat. You would then normally ride to a nylon rode, with the slight cushioning effect that affords. Should they both fail, the chain over the bow roller would be the safety strop. If you had a Samson post, that would be ideal for the chain. Otherwise you really need to add a chain strop to extend it to encompass both mooring cleats.

Belt and Braces enough?

 

[najsmith]

You remember correctly, 2 fairleads & fwd cleats, one bow roller.

Twin Nylon Strops... shoud these be run to the Riser in a Y configuration? ie two strops conected to one rope, connected to the Riser?

I like bullet proof. Currently being told that a 10mm chain attached to the riser will be more than sufficient, but I have that niggle suggesting a rope snubber/backup makes sense too...

 

[pyrojames]

I have a main 32 mm nylon line from the riser to a bollard on the foredeck, then two individual 20 mm lines from the riser to the bollards through fairleads port and st'b. The 20mm lines are simply back up to the main, and not under tension.

1.75" chain seems rather heavy for a Trapper! Mine's pushing 20 tons.

 

[onenyala]

I have attached a short strop with a plastic thimble at both ends to the top of the riser. The pickup buoy also comes off the top of the riser. Initially I secure using the pick up buoy.
I then thread a longer stop which has a soft eye at each end one eye of which is secured to a cleat on one bow out through
the fairlead, through the plastic thimble back through the fairlead on the other bow and then secured on the cleat on that bow.
The result is a bridle. The strops are 18mm diam and the strop which is threaded through the plastic thimble is served for a length of 3mm signal line a length about 8" at its centre which prevents chafe where it renders through the thimble.
This allows equal strain on both parts of the bridle as the boat lies between tide and wind
I have had this set up for three years and it has given no problems.

 

[William_H]

I don't know if my idea will help but my trailer sailer has an eye half way down the bow for attaching a winch I use this as the primary attachment for a rope down to the chain and swivel. There is no chafe place although the U bolt did fail through sideways fatigue. I have replaced it now with a heavy saddle. The rope attaches with a snap shackle. You may have a place to attach a snap shackle near or under the bow roller.

i use a secondary rope onto the deck cleat which is also the first to pick up and last to cast off. I think it vital to have 2 completely different ropes for mooring. In my case the large buoy supports the weight of the chain so ropes only take the horizontal loads of the boat. I either tie the dinghy to the top rope with a long painter (easy for pick up) or just rely on the buoyancy of the rope when I don't leave a dinghy on the mooring. good luck olewill

 

[mikedw]

A lesson learnt: I had twin strops which were forever getting in a tangle with the buoy (passing either side over the top of the buoy before tightening again). So I took one off whilst I was on holiday... But then the single strop twisted so much against the lay that that the splice (6 tucks) came out and the boat went sailing without me.

Set-up / solution (for my 28' 3t boat):
- Main swivel at top of chain riser (under buoy).
- Another swivel attached to the top of other swivel (under buoy) leading towards boat.
- Twin 20mm strops, one with rubber damper over bow roller , the other slighty longer and loose as a backup going to one of the side cleats. Both are strapped together with thin rubber bungee every metre until just before the fairlead or so so they cant go either side of the buoy.
- The twin strops are bound together also eliminate the risk of one strop twisting against the lay of the rope. The ends of each splice are also well sown in with whipping twine.
- Pick up buoy attached to main strop and line used to cleat off over main eye of strop.

I don't have any poly tube or similar for chafe because in my opinion:
- It would reduce the size of rope I can use through the bow roller.
- It doesn't bend completely so introducing two 'hard points' where the rope comes out of the poly tube.
- It can itself chafe on the rope at the ends
- It is harder to inspect the rope
- Being attached to the rope likely means it's location is always fixed avoiding spreading the chafe etc
- My bow roller has very rounded edges on the cheeks etc.

 

[Refueler]

Your riser chain is what ? 1.75" ?????

My swinging mooring which was in excess of harbour board specs was 1" ground chain swivel to 3/4" riser. Blimey and it was hard work getting that up and made fast. Standard harbour board spec was 3/4" ground to 3/8" riser with rope strop of 12mm. That spec was for up to 28ft boats .... Each chain section = to average tide rise / fall.

I always had a rope tail for the pick-up buoy so I could tie it off to pulpit out of the way ... with chain to just before roller. 3 strops of 10mm each .... one went to main mooring post, one went to windlass and last went to another point. So I was never relying on one point of mooring. The combined strops are in fact greater SWL than a single 30mm strop.

2p's worth ...................