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-   -   Mantus Chain Hook (https://www.cruisersforum.com/forums/f118/mantus-chain-hook-117902.html)

colemj 30-12-2013 09:31

Re: Mantus chain hook
 
We don't carry lighter ground tackle, and we don't follow the shallow set steps that JonJo and Sid do - and we NEVER let the windlass carry the load during any part of the procedure. We let out our expected final scope for setting. We just do not connect the bridle until after we set.

In fact, the majority of mono's I watch never deploy a snubber until after the anchor is set. I'm not so sure that is a cat/mono thing or even unusual for mono's.

Of course, we are usually anchored in <15' (often 6'), so full scope isn't too difficult to bring back in if needed. Maybe in deeper anchorages - but the same would be true for monos.

Maybe one difference between mono and cat (in general terms only) is that cats use two engines to back down, so produce more setting force. Perhaps they are able to detect marginal setting better because of this? And this leads some to do the intermediate steps as a test?

Mark

Cotemar 30-12-2013 09:47

Re: Mantus chain hook
 
I have never anchored using a 3 to 1. Always seem to have room to anchor at 5 to1 or more depending on the weather forcast.

I do set the anchor with the 25 foot bridal on with no issues, but do see the value in setting with a shorter line on a cleat. If I ever have an issue, I may try it to see how different it sets.

I used to have a problem with the chain hook coming off as I anchor in 6 feet of water a lot and my bridal lays on the bottom and then the chain hook un-hooks.

The Amsteel Soft Shackle chain hook has a positive connection through the chain link and has eliminated the un-hooking issue.

Bash 30-12-2013 10:18

I use hardware-store galvanized chain hooks that cost maybe $1.50, and have never had problems with one unhooking. The trick is to drop a fathom of chain on the standing end of the hook. The weight of that loop keeps the chain hooked.

Celestialsailor 30-12-2013 10:47

Re: Mantus chain hook
 
Quote:

Originally Posted by Bash (Post 1426966)
I use hardware-store galvanized chain hooks that cost maybe $1.50, and have never had problems with one unhooking. The trick is to drop a fathom of chain on the standing end of the hook. The weight of that loop keeps the chain hooked.

It's interesting...I have had the same experience but always thought they could become "unhooked" some how. So I went to the Mantus hook and although I'm not sure if it was the way I hooked the Mantus up, I did find it unhooked one time. So it may have been that I didn't make sure it was hooked in correctly, was lying on the bottom because I was in 10 ft. of water with 25 feet of bridle out or that for some other reason, just unhooked.
I know you've been to Mananaland many times, so you most likely know of the La Paz waltz. A good test for ground tackle. I do use a hook as a temporary snubber occasionally while backing down. I'm surprised to find the plastic retainer modification to the Mantus hook. Previous advertising lead me to believe it was near impossible to become "unhooked". Seems like this is not the case. Although their are lot's of past ideas that were supposedly infallible. Perhaps from now on, I will choke the Matus hook just above the water, to keep an eye on it. Maybe I'll ask for the modification to the chain and have one of my freeloading friends bring it down when visiting:p.

model 10 30-12-2013 11:11

Re: Mantus chain hook
 
Quote:

Originally Posted by Bash (Post 1426966)
I use hardware-store galvanized chain hooks that cost maybe $1.50, and have never had problems with one unhooking. The trick is to drop a fathom of chain on the standing end of the hook. The weight of that loop keeps the chain hooked.

Believe it or not, that so called "trick" is no guarantee when using the Mantus. It shifts back and forth on the link enough to let the jaw opening line up with the next link and come loose.
A $1.50 part in your ground tackle? Regular chain grab hooks put a side load on the chain. A claw for example has a straight pull but costs more.

thinwater 30-12-2013 11:27

Re: Mantus chain hook
 
Quote:

Originally Posted by estarzinger (Post 1426920)
Sid, interesting . . . so perhaps this a cat thing . . . I still can't understand why it would be. and would be interested to learn why.

As you say it does seem to be at least in part in case the hook does not grab. So, is it because cats set first time less frequently because they (generally) carry lighter ground tackle? That's the only thing I can think of.

A cat thing. The difference may be that some cats (Leopard) deploy from the main beam, centered, and some deploy from each bow (PDQ), off center. If you try to back down while the rode is secured to only one bow a circus insues, with the boat circling to one side and generally looking silly. If I deployed center, yes, it would be much like a mono, but for me, the snubber is connected quite some distance from either bow. Thus, the bridle goes on before power setting. Often as not, I already know whether I have an innitial set by how the boat is lying against the one bow under the presure of wind and momentum alone; if the rode feels light or jumpy I will recover and re-place before trying a power set.

Plain hook. Also, to some extent, pecular to cats setting from a single bow. Because the bridle is attached to 2 bows 20 feet apart, it's not so simple to handle 2 lines in such a way that they neither foul nor get slack (allowing the hook to fall off). It can be done, but it's easy to goof. Using some manner of locking hook-up is thus generally faster on the average. A secondary reason cats often like a locking hook is that touching bottom with the bridle is problematic; a typical bridle will hang 10-15 feet under the water, and we can anchor WAY shallower than that (6 feet is deep).

Mantus hook. Like all snubbers, it must be kept off the bottom. Even an Amsteel soft shackle is going to see wear it doesn't need if it drags back an forth over shells and sand. The fiber part of the snubber will also be dragged on the bottom. Better, keep the snubber off the ground. The strength of the Mantus hook is that it is far less likely to disengauge during lowering.



Why not simply adjust the length of the snubber shorter?
  • Shorter means greater force on the snubber (trig).
  • Some cats don't rig the bridle to cleats (clipped to hard points). This insures the snubber is always equilateral, for better or worse.
  • The weather can come up while ashore, 0 kt the 50 kt in minutes.
  • Cats will sail at anchor if the bridle is too short. With a long bridle most are rock steady, better than monos in a blow.
Why not simply anchor from one bow? Most cat sailors have tried that just once. It doesn't even work for a lunch stop.

So, yes, cats anchor differently in a few details. Mostly the same, but different.

estarzinger 30-12-2013 11:43

Re: Mantus chain hook
 
Quote:

Originally Posted by colemj (Post 1426925)
Funny, setting anchor on the rode only and my foot on the chain, I can tell we are not set before the bearings change enough to be noticeable. I have yet to fail to detect a drag or bad set this way.

You are obviously better at that than I am.

The chain hook on amsteel chain stop is no problem at all - it is connected to a center cleat that the chain travels right next to. It is only a matter of kicking it off the chain when letting out the bridle. It also serves as the chain stop should there be a bridle failure, as well as the chain stop when the anchor is on the roller, so all that "extra work" has valuable purpose to us.

But you do have to unhook the amsteel, hook on the snubber, let out chain and then rehook the amsteel . . . Right . . . . .? I can see that process makes sense if you get great value from "feeling" the chain, but not if (like me) you do not.

Mark

Quote:

Originally Posted by colemj (Post 1426930)
In fact, the majority of mono's I watch never deploy a snubber until after the anchor is set. I'm not so sure that is a cat/mono thing or even unusual for mono's.

Perhaps. I do it before I walk back to the cockpit to go into reverse. It takes the load off the windless and finishes the foredeck work. From the cockpit, if the transits are stationary, I am done and don't have to go forward again.

And, while it does very ocasionally happen, it is a cold day in hell that the anchor does not set first time. I certaintly don't give any thought to changing my procedure to make it easier in case the anchor does not set. It just does not happen that often.


Maybe one difference between mono and cat (in general terms only) is that cats use two engines to back down, so produce more setting force.

Yes, twin engines is also a possible difference. But I am not sure I see it explaining the differences in proceedure. Do you think the reverse thrust is really often significantly higher? The cat twins I have seen are usually half the size hp with smaller props vs the mono, so I would just guess similar thrust. That will obviously differ by model and may not be answerable "generally"

Mark

Quote:

Originally Posted by Bash (Post 1426966)
I use hardware-store galvanized chain hooks that cost maybe $1.50, and have never had problems with one unhooking. The trick is to drop a fathom of chain on the standing end of the hook. The weight of that loop keeps the chain hooked.

You are better at it that I am (and yes, I do hang a chain loop off the hook). I have had hardware hooks fall off the chain. I gave had mantis hooks fall off. I have bent the pin on wichard hooks so I had to use vice grips to get them off. I guess I have had pretty much every sort of hook fail in some way.

......

Celestialsailor 30-12-2013 12:01

Re: Mantus chain hook
 
Quote:

Originally Posted by Guy (Post 1427014)
Believe it or not, that so called "trick" is no guarantee when using the Mantus. It shifts back and forth on the link enough to let the jaw opening line up with the next link and come loose.
A $1.50 part in your ground tackle? Regular chain grab hooks put a side load on the chain. A claw for example has a straight pull but costs more.

I'm not understanding this. Bash was talking about the simple hardware store hook and you are relating it to the Mantus hook some how.
How could the Mantus fall loose? The chain would have to magically ride up 3"s, turn 90 degrees, then pull out sideways. The extra fathom of chain used as a weight loop would keep downward tension on the hook.

colemj 30-12-2013 12:06

Re: Mantus chain hook
 
Like your experience, we very rarely have to set the anchor twice, and most of the time when we do it is because we didn't like the final positioning, or we changed our mind on anchoring spot and moved.

Yes, hook the chain stop, set the anchor, unhook the chain stop and let out bridle, rehook the chain stop as backup. It took me longer to type that sentence than it does to do all of those steps in practice. I am standing right there next to it - it takes no time/effort at all. It takes me longer to hook on the bridle than to mess with the chain stop a couple of times. And that is really only one extra step from your practice - correct? For those who use their snubber short for setting and then let out more after set, it is the same number of steps.

I don't know about engines/props. Our 40' catamaran has two 30hp engines with 17x11 3-blade props in free space. What is a common engine/prop for a 38-42' mono? Our previous 40' mono had both a smaller single engine and a smaller prop in an aperture.

The point I was trying to make there was that perhaps in marginal holding conditions, those backing down with more force may experience poor setting (let's call it overwhelming the available holding potential, rather than poor setting) more often than those who don't back down hard enough to notice. Perhaps this experience is behind the procedures described by the two posters. Perhaps this "preset" thing is more universally common, but we only heard from two catamarans. Again, we don't do the "preset" thing, so I don't have anymore understanding of the reasons for it than you do.

In full reverse on our boat, I estimate that we only put a pull on the anchor system equivalent to ~20-25kt winds. Much less force than I used to think. Anyone pulling less force in a marginal holding spot may be surprised when the winds get to those levels. You have put actual gauges to this - can you estimate a wind speed equivalent to the force you can apply in reverse with your engine? Is it as high as you thought before measuring it?

Mark

Sid at SailAway 30-12-2013 12:08

Re: Mantus chain hook
 
Quote:

Originally Posted by Bash (Post 1426966)
I use hardware-store galvanized chain hooks that cost maybe $1.50, and have never had problems with one unhooking. The trick is to drop a fathom of chain on the standing end of the hook. The weight of that loop keeps the chain hooked.

I believe because you are in a mono and the fact the chain hook never touches the bottom is the reason it doesn't come off. Your bridle is short compared to the 20-25 foot bridles we have to use on a cat. The chain hook on a cat will lay on the bottom and if there is a non-positive attachment to the chain, it will come off. I think that in general cats tend to anchor in skinnier water then the typical mono, thus the reason for the chain hook to be on the bottom more often.

Right now I'm in Staniel Cay anchored in five feet of water at low tide. That's only a foot under the keel as we speak. The Mantus hook has been on the bottom for 8 days now and is still attached even though we do have tidal and wind swings here. The soft shackle idea sounds convincing, but I'm still concerned about chafe. Eight days of dragging through the sand with some rocks and coral thrown in would worry me a bit. I know Cotemar says the shackles are abrasive resistant, but I sure feel good knowing there's a big hunk of stainless down there on the bridle...Sid

colemj 30-12-2013 12:10

Re: Mantus chain hook
 
Quote:

Originally Posted by Celestialsailor (Post 1427059)
The extra fathom of chain used as a weight loop would keep downward tension on the hook.

Only if you are anchored in waters deeper than your snubber (that is 20' for us). For much of our anchoring, a fathom of chain loop would simply drag along the bottom with the rest of the chain.

I have no experience with the Mantus hook, but several reports of it falling off, along with Mantus manufacturing a capture gate for it, leads me to believe that it can fall off.

Mark

Celestialsailor 30-12-2013 12:15

Re: Mantus chain hook
 
Quote:

Originally Posted by colemj (Post 1427067)
Only if you are anchored in waters deeper than your snubber (that is 20' for us). For much of our anchoring, a fathom of chain loop would simply drag along the bottom with the rest of the chain.

I have no experience with the Mantus hook, but several reports of it falling off, along with Mantus manufacturing a capture gate for it, leads me to believe that it can fall off.

Mark

Hi Mark...Yes...I believe this is the key. Keep the hook (any hook) off the bottom. It seems with a Cat, it might be more difficult to do that since you would bridle from each hull to a common point. Plus a Cat can get in closer to less water than a mono. Easier for the hook to touch bottom.

redsky49 30-12-2013 12:38

Re: Mantus chain hook
 
I have had near perfect results as to a chain hook not falling from the rode - can't recall it ever happening once properly set. Perhaps some chain/hook combinations work better?

What I do believe I have experienced, and it is negative, is that when anchored for an extended time at one location, I believe I have abraded the galvanizing from the links and/or the chain hook as a result of metal to metal contact.

As a rule, I gradually extend the snubber line a few inches each day to minimise chafe in the rope, but I don't normally relocate the chain hook on the anchor rode chain.

This has resulted in rust at several locations which I believe correspond to the chain hook placement. Probably not an issue for an overnight stay, but more so for a longer anchoring period.

This might indicate, for my use, a rope "soft shackle" being a better choice.

Any issues with soft shackles parting? I am assuming that the bitter end of the shackle is passed through the eye and then a stopper knot (figure 8?) applied? Correct me if wrong.

Cotemar 30-12-2013 12:43

Re: Mantus chain hook
 
Quote:

Originally Posted by Sid at SailAway (Post 1427065)
Right now I'm in Staniel Cay anchored in five feet of water at low tide. That's only a foot under the keel as we speak.

WOW, Staniel Cay.
Mind If I drop in for a week and wax your boat for you.
Well it's a big cat, it may take me 10 days. :whistling:

Cotemar 30-12-2013 13:12

Re: Mantus chain hook
 
7 Attachment(s)
Quote:

Originally Posted by redsky49 (Post 1427089)
I have had near perfect results as to a chain hook not falling from the rode - can't recall it ever happening once properly set. Perhaps some chain/hook combinations work better?

What I do believe I have experienced, and it is negative, is that when anchored for an extended time at one location, I believe I have abraded the galvanizing from the links and/or the chain hook as a result of metal to metal contact.

As a rule, I gradually extend the snubber line a few inches each day to minimise chafe in the rope, but I don't normally relocate the chain hook on the anchor rode chain.

This has resulted in rust at several locations which I believe correspond to the chain hook placement. Probably not an issue for an overnight stay, but more so for a longer anchoring period.

This might indicate, for my use, a rope "soft shackle" being a better choice.

Any issues with soft shackles parting? I am assuming that the bitter end of the shackle is passed through the eye and then a stopper knot (figure 8?) applied? Correct me if wrong.

Here is how the newer designed Soft Shackles open and close.
Amsteel Blue is used to make these as itís one of the strongest and most abrasion resistance lines made today.
Excellent flex-fatigue resistance
Excellent wear characteristics
Extremely lightweight
Extremely low stretch
Floats
UV stabilized

This is the reason tug boats use it as tow line.
Cruisers use it for rigging and lifelines.

JonJo 30-12-2013 15:00

Re: Mantus chain hook
 
Correct me if I'm wrong, again.

But a 10hp engine with a 'sized' prop is said to produce about 100kg of thrust, 20hp 200kg etc. 2 x 20hp 400kg.

We put our load cell on our chain once and measured the thrust, in reverse, 2 x 3 bladed Volvo props (sized for 20hp Volvos). It was very crude and we simply tried it and did not get very sophisticated (we did not not put on a snubber).

Loads at about 2,800 revs 350kg - but the load oscillated. So some of our 350kg might have been momentum. The yacht would move back, to 350kg and then moved forward, then back, then forward - we did not have a sustained 350kg (and 350kg is about the load on a anchor chain at 30/35knots at 7:1 scope for a 38'cat or 45' mono). I would have thought this oscillation greater with a full snubber attached and much of the reverse load 'stored' in the snubber and thus not transferred to the anchor (which is the other reason for not setting with the snubber on).

If you back up with snubber attached the snubber stretches, stores energy, some of the energy is also stored in the catenary - some of this is transferred to the anchor (but not much as its pretty transitory and an anchor takes 'time' to set (see Mantus' videos - its a slow process) but the yacht is not fixed and much will be transferred to the yacht, moving it forward. Consequently the power set with snubber - I have doubts as to effectiveness cf without snubber.

If our anchor does not set at 3:1 (which would be very unusual) we know its a difficult bottom. We might then move, easier if you have no snubber attached and only 25m deployed than 50m deployed. We would rather move, maybe not far, in the hope of finding something better. I'd rather know its difficult, on the 3:1 scope, than assume its a good hold having set at 7:1. One reason a full 50m deployment is not popular, for us, - if we need to move is that with a shallow chain locker we can only retrieve about 30m at a time, then need knock the tower over. I'd rather spend 30 minutes on the bow and get it right.

I have heard of people who set their anchor, put the engine(s) into reverse and drive hard back using a 'power' stop to set the anchor. We have never done this - we set and slowly increase the revs. As mentioned we can tell if the anchor is set from feel of the chain (and looking at transits and later GPS). But if the chain 'rattles' - we have an issue (maybe 5/16th inch chain is more sensitive to feel than 1/2 inch?)

Attaching a bridle on many cats is not difficult - its just a bit fiddly. The main issue is that the hook needs to be applied under the trampoline which usually means one handed (because there is only room to get one hand through whatever small aperture there is (the hook needs to be also released one handed). Consequently the Witchard hook or any hook with a gate is very difficult. But I see many monos with fold over bow rollers (common on Hanses) and chain hook attachment is well forward when the bow roller is folded out and would be best (easiest) done one handed - so any gated chain hook would need 2 hands on some monos.

But with a common 1m draft, with mini keels, having a fathom (2m) of chain between bow roller and hook is easy. In fact for us 2m would not be enough in a decent blow as the snubbers will stretch more than that.

I do not see that our practice is peculiar to a cat, except we have a bridle not a single line. Many bow arrangements with furlers, bow rollers on almost a sprit etc mean attaching a hook is a bit of a balancing act (or in our case lying on the tramp with one hand through a small hole). Hooks with gates seem overly fiddly (and unnecessary) if you have that fathom, or more, of chain providing the attachment. But havng the snubber so long that it touches the seabed seems, also, unnecessary if you have 10m of deck along which you could run the snubber.

Proof tested standard steel chain hooks are cheap and for us work (though we have used identical design AISI 316L stainless and much more expensive hooks).

But here - Snubbers, long, are like hens teeth. So for most it is simply not an issue:(.


Jonathan

model 10 30-12-2013 20:35

Re: Mantus chain hook
 
Quote:

Originally Posted by Celestialsailor (Post 1427059)
I'm not understanding this. Bash was talking about the simple hardware store hook and you are relating it to the Mantus hook some how.
How could the Mantus fall loose? The chain would have to magically ride up 3"s, turn 90 degrees, then pull out sideways. The extra fathom of chain used as a weight loop would keep downward tension on the hook.

The Mantus hook I have does not have to turn 90deg at all to come off. It just magically jumps up 3 " and comes off. Considering how many times the whole set-up jumps around. I'm not that surprised. I always use some chain hanging down from the hook and it still has jumped off, magically I guess. During a tide shift with wind and chop, all kinds of things happen.
I have used a simple chain grab hook which works on the same principal as the Mantus hook, and don't remember it falling off but they do put a side load on the chain link. A chain claw grabs both sides of the link for an even pull.
The electro plating on cheap $1.50 hook is going to last about a week, not to mention the WLL is way less that it should be.

Celestialsailor 30-12-2013 20:55

Re: Mantus chain hook
 
I'm not doubting that your chain came off. Just wondering how.

Bash 30-12-2013 21:06

Sherman Johnson snubber hook at WM. = $79.99
Soft shackle at WM = $27.99
Chain hook at WM = $7.49
Hardware store chain hook = $1.50

Cotemar 30-12-2013 21:12

Re: Mantus chain hook
 
1 Attachment(s)
Quote:

Originally Posted by Guy (Post 1427491)
The Mantus hook I have does not have to turn 90deg at all to come off. It just magically jumps up 3 " and comes off. Considering how many times the whole set-up jumps around. I'm not that surprised. I always use some chain hanging down from the hook and it still has jumped off, magically I guess. During a tide shift with wind and chop, all kinds of things happen.
I have used a simple chain grab hook which works on the same principal as the Mantus hook, and don't remember it falling off but they do put a side load on the chain link. A chain claw grabs both sides of the link for an even pull.
The electro plating on cheap $1.50 hook is going to last about a week, not to mention the WLL is way less that it should be.

Mantus said they would send you the new Mantus Hook Gate for free.
Their good people and passionate sailors, so e-mail them and get the new hook gate and give it a go. Your problem may be solved right then and there.

Bash 30-12-2013 21:12

3/8" mantus chain hook, purchased from mantus web page:
Stainless = $48.00
Galvanized = $32.00

Cotemar 30-12-2013 21:15

Re: Mantus chain hook
 
Quote:

Originally Posted by Bash (Post 1427513)
Sherman Johnson snubber hook at WM. = $79.99
Soft shackle at WM = $27.99
Chain hook at WM = $7.49
Hardware store chain hook = $1.50

Soft Shackle at eBay = $14.95

NorthPacific 30-12-2013 23:57

Re: Mantus chain hook
 
Quote:

Originally Posted by Cotemar (Post 1427519)
Soft Shackle at eBay = $14.95

Yip and add another $17 for shipping!

Still I have a hook and a rolling hitch is always an option. I am one of those who Sets the anchor and then when it feels good, set s the snubber. Easy enough to take in a bit of chain to set the snubber if in a very tight spot.

As to wear and tear my Samson post is real strong.https://www.cruisersforum.com/images/smilies/smile.gif

conachair 31-12-2013 04:07

Re: Mantus chain hook
 
Quote:

Originally Posted by Cotemar (Post 1427519)
Soft Shackle at eBay = $14.95

Soft shackle from a bit of dyneema lying around..

5 minutes :)

thinwater 31-12-2013 04:20

Re: Mantus chain hook
 
Quote:

Originally Posted by conachair (Post 1427628)
Soft shackle from a bit of dyneema lying around..

5 minutes :)

In this day and age, as basic a seamanship skill as a 3-strand eye splice.

conachair 31-12-2013 05:05

Re: Mantus chain hook
 
Quote:

Originally Posted by thinwater (Post 1427633)
In this day and age, as basic a seamanship skill as a 3-strand eye splice.

And incredibly useful all around the boat. :cool:

https://l-36.com/soft_shackles.php

Mantus Anchors 31-12-2013 15:05

Re: Mantus chain hook
 
1 Attachment(s)
Quote:

Originally Posted by Guy (Post 1425728)
I thought this thing would be the greatest. Not so. In just one funky anchorage it ended up grabbing the chain a second time in it's jaw twice in just 2 weeks time. There was lots of bouncing around and of course tidal shifts. The chain ended up getting hooked in the jaw a second time and for some reason that caused everything to get twisted up into a mess. I had it on a 20' snubber on about 150' of chain in about 20' of water.
Back to a rolling hitch for me.

What size chain do you have, we will send you a plastic gate...
It will prevent any chance of this happening.....
Just email me your address and the size chain and we will hook you up
And guys be patient, it will take us a few days to catch up with all the gate requests... I just need a day to celebrate New Years..:D And the printing will continue...
For this limited time its all free... New Years Gift....
Just remember the gate needs to be used with an "anchor shackle" for the proper fit....
1/4 hook 7/16 inch shackle 1/2 pin
5/16 hook 7/16 inch shackle 1/2 pin
3/8 hook 1/2 inch shackle 5/8 pin
1/2 hook 5/8 inch shackle 3/4 pin

Nicholson58 31-12-2013 15:38

Re: Mantus chain hook
 
5 Attachment(s)
We use a grab hook in the middle of a 1" bridle. The ends of the bridle are cleated to the port & starboard bow mooring cleats. We can shift the bow slightly port or starboard as needed and the strain is off of the windlass. We are too heavy for the rubber snubbers. Anchor rode is 320 ' of 7/16 G4 chain. Secondary anchor on chain/nylon 3-ply with rope gypsy.

JonJo 31-12-2013 16:01

Re: Mantus chain hook
 
Rubber snubbers are a bit of a waste of time or money anyway in an anchor bridle/snubber combination , whether you (the yacht) are heavy or not.

If you use a small one they use up all their elasticity at low loads, you would need 5 x 1 inch rubber snubbers (from memory they are standard length around 15 inches) to absorb the same energy of a 12mm x 10m long piece of nylon cordage. If you simply use one small one they will become ineffective at higher loads - all the stretch will have gone - and its at higher loads you need the elasticity.

(To put another way - if you consider 'catenary' to be overrated then rubber snubbers (unless you use 5 of them!) fall into the same category - all the usefulness disappears at winds over, say 30 knots, probably lower.)

Bigger rubber snubbers are obviously better, have not worked out (nor intend to) energy absorption capabilities.

Rubber snubbers, even small ones, are heavy and very expensive, compared to 12mm nylon.

They are excellent when used in marina mooring environment as their elasticity is contained in such a short length and the loads when attached to a pontoon should not be great. But as part of an anchor snubber system - there are infinitely better options.

Jonathan

Celestialsailor 31-12-2013 16:04

Re: Mantus chain hook
 
Quote:

Originally Posted by Mantus Anchors (Post 1428083)
What size chain do you have, we will send you a plastic gate...
It will prevent any chance of this happening.....
Just email me your address and the size chain and we will hook you up
And guys be patient, it will take us a few days to catch up with all the gate requests... I just need a day to celebrate New Years..:D And the printing will continue...
For this limited time its all free... New Years Gift....
Just remember the gate needs to be used with an "anchor shackle" for the proper fit....
1/4 hook 7/16 inch shackle 1/2 pin
5/16 hook 7/16 inch shackle 1/2 pin
3/8 hook 1/2 inch shackle 5/8 pin
1/2 hook 5/8 inch shackle 3/4 pin

I'm currently using a 7/16" SS shackle with a 1/2" pin for my 3/8" chain, Mantus hook. Are you saying that the gate will not work with that shackle?

Cotemar 31-12-2013 16:05

Re: Mantus chain hook
 
Quote:

Originally Posted by Nicholson58 (Post 1428100)
We use a grab hook in the middle of a 1" bridle. We are too heavy for the rubber snubbers.

They make a rubber line snubber for 1" line.

Falcon Safety Mooring Line Snubber / Compensator - 7/8-1"

Cotemar 31-12-2013 16:08

Re: Mantus chain hook
 
Quote:

Originally Posted by JonJo (Post 1428106)
Rubber snubbers are a bit of a waste of time or money anyway in an anchor bridle/snubber combination , whether you (the yacht) are heavy or not.

If you use a small one they use up all their elasticity at low loads, you would need 5 x 1 inch rubber snubbers (from memory they are standard length around 15 inches) to absorb the same energy of a 12mm x 10m long piece of nylon cordage. If you simply use one small one they will become ineffective at higher loads - all the stretch will have gone - and its at higher loads you need the elasticity.

(To put another way - if you consider 'catenary' to be overrated then rubber snubbers (unless you use 5 of them!) fall into the same category - all the usefulness disappears at winds over, say 30 knots, probably lower.)

Bigger rubber snubbers are obviously better, have not worked out (nor intend to) energy absorption capabilities.

Rubber snubbers, even small ones, are heavy and very expensive, compared to 12mm nylon.

They are excellent when used in marina mooring environment as their elasticity is contained in such a short length and the loads when attached to a pontoon should not be great. But as part of an anchor snubber system - there are infinitely better options.

Jonathan

WOW, JonJo,
Not a word you said here is valid.

JonJo 31-12-2013 16:53

Re: Mantus chain hook
 
The maximum load you can apply to a 1 inch snubber is 280kg. The limit is set by the manufacturers - though you could go beyond this - but the snubber might break. The maximum energy that this snubber will absorb is 233 joules.

If we take a 5t yacht moving at 1kt, surging at anchor, then the energy of the yacht is 1250 joules.

In order to absorb that energy you would need 5 snubbers.

A nylon rope will absorb considerably more energy - a 10mm x 10m long rope will easily absorb 1250 joules. In fact the 10mm nylon rope can absorb over 7,000 joules but this will be at half its max elasticity - so lifespan might be short! You could use a thicker piece of nylon, which will absorb less energy at the same load but last much longer.

I have not checked how much snubbers cost in America, here they are expensive (and heavy) - maybe you can quote me for one snubber vs 10m of 10mm nylon (either 3 ply or anchor plait). Note to compete with energy absorbing capabilities of nylon you will need 5 x 1 inch rubber snubbers. Maybe you can also weigh a 1 inch rubber snubber and compare it with the weight of 10m of 10mm 3 ply

Jonathan

Horror Hotel 31-12-2013 17:16

Re: Mantus chain hook
 
I use a high quality galvanized chain hook that's nothing fancy just like you would find on a logging skidder. It's randomly fallen off once or twice a year. I just got my SS Mantus 3/8 hook today and I really think it's gotta be a improvement. Nothing's perfect, but since it's got a bunch of metal where the old hook had none I think it's gonna be a winner. Sure it might come off, but that's life. Everyone here is so serious, lighten up guys. We're slackin off in the sun, life's good.

Cotemar 31-12-2013 17:43

Re: Mantus chain hook
 
JonJo,

Rubber snubbers for 1" line cost $56 usd which is cheap.

Take that rubber snubber and put a 1” line through it and then around it three times and I will lift your cat out of the water any day of the week and bounce it like a rag doll.
Your numbers are all wrong as usual. Last year you told me I would break them after three anchoring’s.
I used them all season up to 45 knots. They eliminated the shock load from strong wind and waves.
I never had that feeling of sliding backwards and hitting a dead stop. Shock load gone.
They look as new as the day I put them on.

I hate to pour cold water on your enthusiasm.

thinwater 31-12-2013 18:00

Re: Mantus chain hook
 
Quote:

Originally Posted by Cotemar (Post 1428162)
...
Your numbers are all wrong as usual....

Is it possible you are not referring to the same rubber snubber design? There are many out there. Explaining which numbers are wrong may bring clarity.

However, unless they can stretch 4-6 feet at loads of 1000-2000 pounds, the math is in favor of a long nylon snubber. He has presented numbers, you have delivered unquantifiable anecdotes; I suspect your rough anchorage and your boat are both different from his.

JonJo 31-12-2013 18:05

Re: Mantus chain hook
 
Cotemar - if that is your experience then I am sure you are right.

Jonathan

Cotemar 31-12-2013 19:01

Re: Mantus chain hook
 
2 Attachment(s)
My 5/8 inch diameter 3 strand nylon bridle snubber has a tensile strength of 11,650 lbs.
The rubber snubber with three turns is rated for storm surge conditions.
The proper rubber snubber not only stretch’s on the three turns, but also coils and compresses the rubber core in 3 dimension’s.

When I back down on this cat bridle snubber with two 30 hp diesel engines at 2800 rpm with 3 bladed props, These rubber snubbers are at 1/3 stretch.

This compact 20 foot cat bridle setup accomplishes the same snubbing power as JonJo’s climbing lines running down his decks to his stern cleats, But I will not kill anyone as my Bridle snubber is all forward of my Seagull Striker cross beam.

Wind and wave shock loads are gone.

JonJo 31-12-2013 20:26

Re: Mantus chain hook
 
Cotemar

I am interested, seriously, in your rubber snubbers. You mention they are rated for storm surge conditions with 3 turns, the 3 turns as illustrated in your image. The restricting feature of your snubber are the 3 turns - the snubber simply cannot stretch more than the '3 turns'. Consequently the 'rating' for a storm surge does not mean very much in that as long as you keep the 3 turns the snubbers will take whatever load the cordage will take (you will never stretch it beyond whatever those 3 turns restrict it to).

The cordage will stretch - but in terms of the length of the 3 turns - not very much. Basically beyond about 30 knots any excess load is taken by the cordage - not the snubber.

My data is based on actually testing a 1 inch by 18 inch rubber snubber As far as I can make out there are a number of manufacturers and the products are all similar - but your snubber seems slightly higher priced and might be different. I have checked Taylor Made, Forsheider and Unimer (not sure of the spellings) and they are all the same specs. Max stretch is about 60% - and there are very few polymers that would be applicable and cheap that are better then this.

West Marine sell a 1 inch by 18 inch rubber snubber for around $50 and you can buy 30' of 3/8th inch Mega Plait for around $39. This snubber (and this is similar to the one I tested) will absorb around 250 joules of energy and that is at the limit of stretch suggested by the manufacturer. The 30' of 3/8th nylon at 50% of breaking load absorbs over 7,000 joules. 50% of stretch is excessive and not to be used - but 30' of 5/8th inch nylon can absorb 4,000 joules at 20% of stretch so a better option at higher loads and has no need for a rubber snubber - the nylon does it all by itself and works through the complete wind range. Recall that a 5t yacht at 1 knot develops 1250 joules, a 10t yacht twice that at the same speed. A rubber snubber is very effective at low wind speeds but then depends completely on the strength of the cordage beyond 30knots (and I think stops working below this wind speed).

My view is rubber snubbers are great in a marina application, they are more expensive than cordage, they are heavy for what they do (could not check the weight so this comment is subjective) and they reach the limit of their energy absorbing ability (when used as an anchor snubber) at relative low wind speeds.

But none of this matters - if your chain (size and length) deployed, combined with your nylon snubbers + the rubber snubbers works for you and you are happy then that is all that matters. There are other options which are cheaper and maybe more effective. None of these items, chain, nylon, rubber, works in isolation - but the 'loss' of chain catenary and the rubber snubber both lose effectiveness just as you actually need it.

But if you can advise the specific brand of snubber I would be very interested to check it out.


I note your comment about safety - and a comment well made.

There is conflict with multis (and monos come to that) as to how to get a 30' snubber into the rode system. If you have it all outboard then in light winds the snubber/chain attachment rubs on the seabed, chain hooks fall off and the snubber potentially abrades (nylon is not very abrasion resistant). If you have it all inboard and it fails you have a cable that would seriously injure someone. (Though I'm not sure that someone standing on a yacht bow is immune from having an arm cut off (or worse) if 30' of snubber fails outboard). We run our snubber/bridle through the deck stanchion bases- its basically contained to 5' lengths. On a mono you could run it through Dyneema loops tied to the toe rail - containing the snubber is not an issue. But to have a snubber much shorter than 20' and you will lose energy absorbing potential.

Jonathan

NorthPacific 31-12-2013 20:35

Re: Mantus chain hook
 
40-15 to Jonathan


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