Anchoring- was i wrong???

[Mike k]

Hi all went into the mersey last saturday ( 27ft mobo about 3 tonnes i think) and anchored- i released anchor by the electric windlass powerdown and boat steadily dragged back to set anchor. forgot to mention the brake was loose and some rapid freefall occured - not nice.Anyway i tightened gipsy clutch and boat held perfectly well however i have been told not to let the windlass hold the chain but to use a check chain to take the strain. If anybody says i should snub the chain please explain whatr this means as i have read this on a american website but cant find out what this means.
I would be most grateful for any advice

thanks Mike

 

[Robin]

For a short stay in good conditions, no problem. Windlass shafts and inner workings however are not designed to take high snatch loads so best practice is to use a snubber line to transfer the load to a deck cleat. A snubber line is a length of line, preferably nylon which is stretchy, that you attach to the chain (we use a chain hook, otherwise tie a rolling hitch) and to your deck cleat, then let more chain out so the load is all on the snubber line and the chain hangs in a slack loop over the bow, but still on the windlass ready if needed. A nice refinement that we always use is to have a rubber 'mooring compensator' or 'gondolastic' that looks like a dog bone wound into the nylon line (ie the line is wound around it). This alows more stretch and eliminates snatch as the boat swings in the wind. This makes for a more secure set up, because snatch loads can cause the anchor to break out, plus it is quieter and more comfortable on board, especially if you sleep in the forward cabin.

 

[Mike k]

Thanks Robin- my nearest cleats are offset left and right for bow lines would the strain not tend to drag the chain off the roller.Anther thought is the chain is coonnected to the boat in the anchor locker but not sure if this is strong enough to take a 'snub' chain- any suggestions?

 

[Poignard]

Thanks Robin- my nearest cleats are offset left and right for bow lines would the strain not tend to drag the chain off the roller.Anther thought is the chain is coonnected to the boat in the anchor locker but not sure if this is strong enough to take a 'snub' chain- any suggestions?

Nothing to stop you having a line to each cleat.

 

[Mike k]

Would the towing eye but good enough to take a snub line/check chain?

 

[Robin]

Your cleats are in the usual places, you might have fairleads to take the line over closer to the bow? The pull is between the anchor snubber line attachment point and the deck cleat, the chain above that to the windlass should be hanging in a slack loop off the bow roller. If you have a 2nd bow roller lead the snubber line over it instead. Another option is to have the snubber made as a 'Y' with the stem of the 'Y' (centre of the line) hooked on the chain and the two arms to your two deck cleats. Difficult to describe but easy to do!

 

[Robin]

Would the towing eye but good enough to take a snub line/check chain?

Not sure. Some big boats (USA especially) use a bow eye but then the eye is designed for that and the use is to get the lead lower, thus reducing the chain angle in crowded spots so shorter scope can be used.

Two lines also works.

 

[Ripster]

I use a single snubber line with a chain hook and mooring comp and this is attached to one of the offset bow cleats - works fine. If we are overnighting, I rig up two like a sort of harness to spread the load over both bow cleats.

 

[Mike k]

thanks Ripster can you describe a chain hook and mooring comp pls

 

[hlb]

I've tried every thing with my chain hook, but it always falls off. Would look for a D hook next time, that the chain could not fit through.

 

[David of Essex]

Any photos of the above ideas would be grateful
David

 

[carlton]

 

[Robin]

I've tried every thing with my chain hook, but it always falls off. Would look for a D hook next time, that the chain could not fit through.

A proper chain hook shouldn't fall off if it is holding the weight of the chain below it and the chain above it is therefore slack, they do need to be the correct size for the chain used. The hook goes between the links, not hooked into a link of course as I'm sure you know, but just in case others don't. When they can fall off is in setting the snubber line and the chain hasn't yet been slackened off yet to allow the weight/pull to come onto the hook but after a few times you get the knack of keeping some tension on the hook until the chain above is eased off.

I prefer a proper chain hook, others use a Wichard shackle and others again tie the line to the chain with a rolling hitch, cheapest but may need a knife to cut it free in an emergency.

 

[David of Essex]

Thanks a better understanding now.
David

 

[KevB]

I always let the clutch off and let the anchor drop into the water. Much better 20 odd kgs hitting the sea floor for holding than gently laying it down. I find anyway...

 

[RogerRat]

thanks Ripster can you describe a chain hook and mooring comp pls

A chain hook is the sort of thing you've picked up in a chandlery and wondered what the hell it was. It's a very robust looking hook with parallel side slot, made in one piece with no swivel arrangement, just an eye for splicing to a rope or line.

It is important to know the size of your chain though. I'm guessing that your anchor chain will be 6mm and you must buy a 6mm or 1/4" (8mm or 5/16" stamped on them) chain hook if this is the case. If you get the right size, it can't fall off!

If you ask in any decent chandlery for a '6mm Chain Hook' you've a 95% chance of getting what you need from the first person you speak to. Don't buy any other type of hook or snap shackle, they are not for this purpose and will either fail or you'll find it hard to remove when you least want it to. Chain hooks are strong and have a confirmed load capability, the rope you attach if max. diameter will be stronger than your anchor chain so these won't be your weakest link.

For short stays, the simplest way to fit this is to splice it to a line of the max. diameter that will fit through it's eye and then splice or tie a loop just large enough to to slip over your chain gypsy or winch drum. With this load taking line attached to the chain as it goes over the bow roller, just release the tension on the windlass to ensure all the load is taken by this line and not the drag clutch/brake.

This is the simplest way to use a hook and remove load from the windlass, BUT is not a snubber as the line is too short with no stretch. Still, I'm happy to overnight on this arrangement.

 

[RogerRat]

I always let the clutch off and let the anchor drop into the water. Much better 20 odd kgs hitting the sea floor for holding than gently laying it down. I find anyway...

This is ok in shallow water but if it snags on a longer drop it could do damage to your windlass with a heavy shock load. Ouch!

Also, ok for the anchor to hit the bottom but not for the chain to follow on to quickly, the chain needs to be laid out and NOT dumped in a heap, after all it's the chain that anchors the boat and the hook that holds the chain. It's the long sweeping curve of the rising chain called the 'catenary' that reduces the need for shock absorbing snubbers.

Apols for all the bull**** classroom stuff but I just like the word, latin for chain I think.

 

[PCUK]

You can also use a chain stopper (Lewmar sell them on their website) and rely on the catenary (the curve in the hanging chain) to take out shock loads. I pass a bolt through the bow roller body and chain. As long as you have enough chain out the catenary will cope fine.

 

[Ripster]

I pass a bolt through the bow roller body and chain. As long as you have enough chain out the catenary will cope fine.

I tried the same using an 8mm drop nose pin through my 10mm chain, just over a lunch time stop, being lazy and not wanting bother with the normal hook and line system to the cleat. When I came to release everything, the pin had bent and locked itself in the holes - had to tap it out with a hammer!

I think with my arrangement (on reflection) it was probably the fairly wide bow roller channel and therefore the length of exposed pin that did for it. In a narrower channel with a shorter gap to bridge the pin "might" have held OK.

 

[Mike k]

many thanks

fantastic response many thanks to all it has been most helpful and i have orderes the parts to make up a rig that will go over both cleats and snubber to chain with shackles/chain hook.