Motor boat mooring strop suggestions..

[wipe_out]

We are moving the boat to a swing mooring in a few weeks.. Looking at the forward cleats I don't feel they are strong enough to trust in the worst conditions so the plan is to use the D ring on the hull and the primary connection point for the mooring strop.. The issue is that it's not possible to reach from the fore deck and hover boards haven't been invented yet..

So I need to permanently attach a rope to the D ring that will be secured on the fore deck when underway then when mooring up it will have to be connected to a rope (or chain) coming up from the buoy.. So essentially some sort of two piece strop with a shackle or similar in the middle..

What would be the best way to go about this? Or is a two piece strop a bad idea to start with?

Any suggestions (and links to products to use) would be appreciated..

Thanks..

 

[estarzinger]

First, best material would be dyneema single braid. Dacron double braid would be the second 'economy' choice. You don't say how big a boat so we can not guess the likely loads.

Second, either splice it directly to the hull ring, or cow hitch it. So you need a loop splices to that end.

Third, use a dyneema soft shackle to connect to the mooring line. That is strong, inexpensive, corrosion free, and not going to ding your gel coat.

 

[wipe_out]

First, best material would be dyneema single braid. Dacron double braid would be the second 'economy' choice. You don't say how big a boat so we can not guess the likely loads.

Second, either splice it directly to the hull ring, or cow hitch it. So you need a loop splices to that end.

Third, use a dyneema soft shackle to connect to the mooring line. That is strong, inexpensive, corrosion free, and not going to ding your gel coat.

Hi, Sorry.. Boat is 26ft and weighs about 3000kg..

 

[estarzinger]

Hi, Sorry.. Boat is 26ft and weighs about 3000kg..

Ok, then you are unlikely to see more than 650kg load. For a 3:1 safety factor, you might size everything for 2000kg. That is 3/8" Dacron double braid, with a 1/4" dyneema soft shackle (which is more like 4000kgs, but extra is nice here for chafe).

 

[Daydream believer]

The load carrying of the rope is pretty irrelevant. The big problem is wear. iIsuggest 25 mm multiplat with a nylon eye to the boat. do not put any rope straight to a ring or shackle without a thimble.
If you use a nylon one you may be able to split the thimble with a hack saw at the pointed part . Hook it round the ring then put the rope round & splice.
A shackle would not actually do much harm as its movement is limited. In any event all shackles should be moused

where the rope meets the other strop do not just pass it through a loop as it will wear super fast. not sure how you are going to join the 2 parts

If the combined strop is very long the buoy will rub along a lot of hull & by the end of the season there will be a lot of damage.

I must admit that I have not seen a boat tied as you propose. The joining of the 2 strops seems a receipt for problems

I would suggest that you take 2 separate lines to the cleats & pull the buoy up tight. Never leave the boat on just one strop.
Where the strops meet the buoy ring use 2 shackle - not 1- as when one shackle come undone you do not loose both strops

Believe me re the last comment. I look after 80 moorings on the Blackwater & we loose a couple of boats every year due to shackles coming undone, strops incorrectly tied, strop wearing through etc etc. Most owners use a chain hung loose & a rope strop to take the load. If it breaks the chain takes up, but a chain tends to be hard at wearing fairleads etc & snatch more in a swell so it is used as a backup rather than the main one

I have supplied a few lengths of chain with a multiplat Eye spliced on . This is gentle on the hands & cleat. I also splice a piece of 6 mm line in the splice so one can tie the loop to the cleat to stop it jumping off. The line is always to hand & the owner is less likely to forget it

Finally I have seen boats the size of yours drag 1 tonne weights down the river so the load ( partly due to snatch I suspect) can be more than 600Kgs. Although I accept that a 1 tonne weight does not weigh 1 tonne in water- Specific gravity etc!!!!

 

[wipe_out]

..The joining of the 2 strops seems a receipt for problems...

I agree but I don't believe the cleats are strong enough to withstand heavy pounding in a storm and I can't reach the D ring on the bow.. Not sure how else to do it other than joining two strops in the middle somehow..

Had planned to have a secondary strop to the cleats anyway as a backup..

 

[oldbilbo]

Looking at the forward cleats I don't feel they are strong enough to trust in the worst conditions so the plan is to use the D ring on the hull and the primary connection point for the mooring strop..

Many production boats find their way into owners' hands with foredeck cleats quite inadequate for the purpose. Have you considered upgrading these cleats and, rather more significantly, the backing material that such cleats are fastened through/to....?

This is a task that many have addressed - as have I - and is something within the capability of the majority of 'handy' boat owners.

I'd also encourage you to look critically at the D-ring fitted under the bow. From some experience, if the foredeck cleats are inadequate, this D-ring is just as unlikely to be strong enough for the likely snatch loads in heavy seas, on an swinging mooring..... and you run the risk of this pulling right out, taking a chunk of the bow structure with it.

Why don't you post some pics of your present foredeck and D-ring arrangements AND the relevant through-bolts where they are visible inside the boat? People on here can then make better-tailored suggestions.

Another source of useful guidance is the Practical Boat Owner article 'How Safe Is Your Mooring' from June 2011/Issue 535

 

[wipe_out]

Why don't you post some pics of your present foredeck and D-ring arrangements AND the relevant through-bolts where they are visible inside the boat? People on here can then make better-tailored suggestions.

Deck cleats are like these.. Apparently screwed into aluminium plates.. How thick/wide I have no idea which is why the D ring seems the stronger connection point..
http://www.downwindmarine.com/images/P/890397.jpg

D ring is bolted through the hull and through a large wood block behind it.. Unfortunately I have no photos but removed it's probably something similar to this..
http://i.ebayimg.com/00/s/MTYwMFgxMTk1/$(KGrHqF,!o0E9cvI8dQQBPrnnzj+4w~~60_35.JPG?set_id=880000500F

 

[oldbilbo]

Deck cleats are like these.. Apparently screwed into aluminium plates.. How thick/wide I have no idea which is why the D ring seems the stronger connection point..
http://www.downwindmarine.com/images/P/890397.jpg

D ring is bolted through the hull and through a large wood block behind it.. Unfortunately I have no photos but removed it's probably something similar to this..
http://i.ebayimg.com/00/s/MTYwMFgxMTk1/$(KGrHqF,!o0E9cvI8dQQBPrnnzj+4w~~60_35.JPG?set_id=880000500F

I have fitted cleats just like the ones you indicate above....

...and I expect them to be fully up to the job, in lumpy weather and seas, for a 27' sailboat displacing about 3000kg. However, my cleats are very solidly through-bolted via wide pads above and below deck, using 8mm s/s bolts, AND they are intended for use as closed fairleads when moored/anchored, with the boat's warps - and their loads - being taken to a dedicated strongpoint ( bitts ) fitted solidly onto the deck.

When heavy pitching is anticipated, further lines can be attached to those above, and secured to other strongpoints further aft, so spreading the loads. That was normal practice not all that long ago, and could be helpful to the OP when leaving the boat unattended.

The OP's primary boat ropes could be fitted with snubbers, such as the type shown below, which help to some degree in absorbing the snatch loads which cause damage. Bigger is better..... Of course, robust provision must be made to mitigate chafe. It is false economy to save a few quid on chafe protection
and risk the total loss of the boat. Besides which, one's insurers' claims adjuster is bound to ask the question "What steps did you take to prevent your boat ropes chaffing through?"

I am not at all keen on the concept of securing the boat to a D-ring fixed into the bow, and leaving the boat unattended on a short scope. Nor am I keen on having deck cleats, whether used as fairleads or not, secured by some form of screws into aluminium plates and not by through-bolting. I would expect such to pull out, and I sense that the OP has a similar concern.

 

[William_H]

I am assuming that the Dee ring you speak of is a connection half way down the prow that is designed to allow the boat to be winched onto a trailer. I use a similar thing on my trailer sailer for primary swing mooring attachment. It has the advantage of no where for the rope to chafe on and it is under and back from the top of the bow which might give some protection from another boat adrift chafing the rope. However there is a lot of sideways load on this fitting and the original a 3/8 U bolt turned down to 5/16 for nuts on the inside fatigued at the reduction of diameter.
Obviously I have a second rope to cleat on the deck as a back up but also as the first pick up. So I arrive at the boat in dinghy disconnect the lower bow attachment then later cast off on the deck cleat. On departure the last thing I do from the dinghy is to attach the lower bow attachment which is a large snap shackle. No problems in 25 years do it this way.
You would want deck cleats that give some confidence in holding the boat alone. I would suggest larger cleats with the capacity to hold larger ropes as well.
Incidentally a lot of big power boats around here have trouble picking up a rope in the water because the bow is high above the water. A stainless steel rod is attached to the top of a decent sized buoy with the mooring rope going through a ring on the top. Thus the mooring rope although dropped in the water is lifted up about 1 metre above the buoy where crew can easily hook it with boat hook. good luck olewill

 

[Iliade]

Any suggestions (and links to products to use) would be appreciated..

Thanks..

6 mm blue poly is the traditional solution for mooring motor boats ;-) [Only Joking! Well someone had to...]

I would never use a single strongpoint for a permanent mooring and I'm not convinced that the bow fitting you mention is up to the job. It is really only designed for winching onto and holding hold the bow forwards on a trailer.

 

[webby]

Deck Fitting

At the risk of appearing dim! (well if the cap fits...). Can anyone suggest what the fitting indicated on the attached picture is for? Mooring strop fairlead? There is an anchor in place now.

 

[Lakesailor]

I agree but I don't believe the cleats are strong enough to withstand heavy pounding in a storm and I can't reach the D ring on the bow.. Not sure how else to do it other than joining two strops in the middle somehow..

Had planned to have a secondary strop to the cleats anyway as a backup..

So....when you leave the boat on it's mooring, are you in a tender? The sort of thing you could go around to the the bow and fit your strop from?

 

[wipe_out]

So....when you leave the boat on it's mooring, are you in a tender? The sort of thing you could go around to the the bow and fit your strop from?

No, in the water taxi.. Usually with a few others..

 

[Lakesailor]

OK Get a Vetus s/s bollard for you foredeck and some fairleads to run double strops over the bow. Fit the bollard with a large ply backing pad.