Anchor snubber hook

[noelex]

Isn't it the 'SNATCH' loads its there to catch ? Peak loads will be same whatever ... its the severity of the snatch that's being catered for ?

Having some stretch in the anchoring system will will dampen out the peaks and troughs in the load curve. This will reduce the peak loads the anchor will experience.

You do need to be careful that there is not so much stretch that the boat can "slingshot" forward. This can create a higher rather than a lower peak load as the boat can develop considerable momentum as it subsequently moves backwards.

In practice, in strong wind, many yachts have snubbers that are too short, and thus providing too little stretch, but it is possible to introduce too much stretch. Some experimentation in the ideal length and/or diameter of the snubber rope for your boats characteristics is sensible. More is not always better. Around 10-14m of appropriately sized nylon is a good starting point (assuming all chain rode).

The stretch of the snubber will only be beneficial in strong wind, but personally we deploy this every time we anchor as forecasts are not always right and the snubber is easy to deploy.

 

[Mr Cassandra]

Having some stretch in the anchoring system will will dampen out the peaks and troughs in the load curve. This will reduce the peak loads the anchor will experience.

You do need to be careful that there is not so much stretch that the boat can "slingshot" forward. This can create a higher peak load as the boat can develop considerable momentum as it subsequently moves backwards.

In practice, in strong wind, many yachts have snubbers that are too short, and thus providing too little stretch, but it is possible to introduce too much stretch. Some experimentation in the ideal length and/or diameter of the snubber rope for your boats characteristics is sensible. More is not always better. Around 10-14m of appropriately sized nylon is a good starting point.

That's why I introduced the stern mooring spring to the equation. You can see the spring compress and relax with little stress to the warp/snubbed line.

Think about it is simple the spring evens out the load on the line

 

[biscuit]

I just put a rolling hitch on the chain (10mm rope with a rubber anchor snubber, one end around a bow cleat) then let the chain out until it hangs slack.

My heavy weather snubber is something else, long lenghts of 3 strand nylon hitched to my midships or stern cleats. Ony ever used once in earnest, I confess.

 

[Refueler]

Having some stretch in the anchoring system will will dampen out the peaks and troughs in the load curve. This will reduce the peak loads the anchor will experience.

You do need to be careful that there is not so much stretch that the boat can "slingshot" forward. This can create a higher rather than a lower peak load as the boat can develop considerable momentum as it subsequently moves backwards.

In practice, in strong wind, many yachts have snubbers that are too short, and thus providing too little stretch, but it is possible to introduce too much stretch. Some experimentation in the ideal length and/or diameter of the snubber rope for your boats characteristics is sensible. More is not always better. Around 10-14m of appropriately sized nylon is a good starting point (assuming all chain rode).

The stretch of the snubber will only be beneficial in strong wind, but personally we deploy this every time we anchor as forecasts are not always right and the snubber is easy to deploy.

Mine wasn't so much a question as peak load will never change because of a snubber - its a product of forces exerted on the boat and system. All you are doing with a snubber is reducing the shock effect or 'snatch'. In effect causing the i9ncrease / decrease of load from to peak to be over a few seconds instead of near instant.

I do a lot of anchoring in Swedish / Finnish islands, did a lot in Solent when boat was there - but never use snubber. Yes - I'm an all chain guy ... and if the chain is 'grumbling' on the bow roller - I try to find out why ... usually its because the anchor is dragging or resetting. Even with strong weather generally my all chain rode is reasonably quiet based on sufficient riding scope and well set anchor.

 

[rotrax]

My use of a snubber and chain hook is what I suspect the majority use it for - over the second bow roller, let some chain out to take the load off the windlass.

In heavy weather it is long enough to be positioned from the centre cleat where its inherent elasticity damps surges.

Well so far anyway.

 

[Humblebee]

If the pressure comes off as setting, the hook disengage s itself. What to do? Use an ordinary shackle?

How about one of these, perhaps permanently spliced onto a suitable snubbing rode?

Force 4 Large Chain Gripper 10-12mm chain | Force 4 Chandlery

 

[mrangry]

I just put a rolling hitch on the chain (10mm rope with a rubber anchor snubber, one end around a bow cleat) then let the chain out until it hangs slack.

My heavy weather snubber is something else, long lenghts of 3 strand nylon hitched to my midships or stern cleats. Ony ever used once in earnest, I confess.

Like you I just use a rolling hitch rather than a hook. If you need to remove in a hurry a simple cut with a knife and its free, a hook not so quick

 

[RichardS]

Like you I just use a rolling hitch rather than a hook. If you need to remove in a hurry a simple cut with a knife and its free, a hook not so quick

Wouldn't you just cut the snubber?

Richard

 

[dunedin]

How about one of these, perhaps permanently spliced onto a suitable snubbing rode?

Force 4 Large Chain Gripper 10-12mm chain | Force 4 Chandlery

Like at least one other poster on here, we use TWO ropes and connectors on our anchor overnight:
1) A longish snubber with rubber compensator on it, with open hook lowered well below the bow - this has never come off in several hundred uses, and the weight of the chain holds on securely, but in theory could possibly do so (or the rope part)
2) A short rope strop which remains on deck, with one of these closed chain shackles (per Humblebee’s link) which cannot come off - which is the fallback
The short one and hook is colloquially known on board as the “lunch hook”, as it is used on its own for short lunch stops

 

[thinwater]

ReFueler:

Isn't it the 'SNATCH' loads its there to catch ? Peak loads will be same whatever ... its the severity of the snatch that's being catered for ?

Having some stretch in the anchoring system will will dampen out the peaks and troughs in the load curve. This will reduce the peak loads the anchor will experience.

You do need to be careful that there is not so much stretch that the boat can "slingshot" forward. This can create a higher rather than a lower peak load as the boat can develop considerable momentum as it subsequently moves backwards.

In practice, in strong wind, many yachts have snubbers that are too short, and thus providing too little stretch, but it is possible to introduce too much stretch. Some experimentation in the ideal length and/or diameter of the snubber rope for your boats characteristics is sensible. More is not always better. Around 10-14m of appropriately sized nylon is a good starting point (assuming all chain rode).

The stretch of the snubber will only be beneficial in strong wind, but personally we deploy this every time we anchor as forecasts are not always right and the snubber is easy to deploy.

Data needed!

I have tested all-rope rodes, and found (in the place I tested, with the variable wind at the time) that if the rode were too long or excesivly stretchy (small nylon), the extent of yawing would increase as a result of the "slingshot" you speak of, and that because the wind sees the boat from the side when yawing, forces were increased.

I am not convinced (would need to see the data) that a long snubber on primarily chain rode could do the same thing. I have tested many snubber sizes and lengths, and up to about 20 meters and the thinner it gets, the rode tension is lower. More than 20 meters I considered impractical for snubbers.

I am also not convinced (but could be with data) that the slingshot effect and the affect of gathered momentum cane increase rode tension above that with a shorter snubber. I could not even see that effect with rope rode. Uncomfortable, yes. Increased yawing, very likely. But not momentum alone.

Yes, like springs and shock absorbers on a car, there is an optimum range. At one end is an un-sprung fork truck (very rough) and at the other and uncontrollable car on early balloon tires. Every boat and circumstance will have a slightly different optimum. I've had a variety of boats, and the best family of answers was different for each.

 

[thinwater]

Here's another vote for connecting the chain with a dyneema shackle. This is the chain end of our snubber - backsliced octoplat onto a single anchor link.

A single link of chain, to keep the Dyneema from slicing into the nylon. Clever. Perhaps it is not needed, but it can't hurt either.

 

[Neeves]

There is an article in the July issue of YM on snubbers for monos and there will be a follow up article on chain hooks 'sometime' later.

We use a 10mm x 30m snubber, 2 off, a bridle with 6mm chain on a 38' cat. There is no slingshot effect, data from those who experience it would be interesting. Our arrangement reduces the impact of yawing and chop and settles the cat. Our bridle commences at the transom and can be adjusted from the comfort of the cockpit using the sheet winches.

Our chain hook, a bridle plate, sits, maybe, as much as 2m forward of the bow roller - read the article. Adding a second bridle (surely you carry a back up snubber/bridle) would be easy, simply add another hook deploy some more chain - if this is difficult I'd suggest you might think of replacing sailing with lawn bowls.

We use a second strop as a back up in case the bridle fails - it is always applied and protects the windlass. It is located solely inboard. An alternative is a chain lock. We use the same device to secure the anchor on passage.

Using a soft shackle on 10mm or 12mm chain is probably a doddle - using it in 6mm chain is like trying to thread a needle whilst riding a bicycle on a bumpy road.

We use a bridle plate but have used a hook with our bridle. It can be applied with one hand, and if there is a 'gate' to stop the chain falling out (easy to add to many hooks - see the future article (or send me a PM) it can be operated with the thumb of the same hand. Tying a hitch is a well worn practice for a snubber, or bridle, it takes 2 hands. If you use a soft shackle the idea of cutting it off in an emergency is an interesting idea. Much easier to winch in the snubber/bridle using the sheet winch(es) and simply lifting the hook or bridle plate off (only one hand needed).

Viking Anchors have copied our bridle plate and have modified it for monohulls. I have not actually seen either of their devices, other than pictures - but they appear to have the right idea. Note in the article in Cruising World - the expensive chain hook failed. We have used the same chain hook - the spring pin gate bent - they are positively dangerous.


The art of snubbing, in the nicest possible way | Mysailing News

Safety at Sea: Surviving a Powerful Storm in the Med

How to: Dealing with Snatch Loads in an Anchorage

Anchor Snubber Tips

and then the July issue of YM.

Jonathan