Mantus Chain Hook

[thinwater]

Originally Posted by estarzinger

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]

Originally Posted by colemj

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

Originally Posted by colemj

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

Originally Posted by Bash

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]

Originally Posted by Guy

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]

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]

Originally Posted by Bash

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]

Originally Posted by Celestialsailor

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]

Originally Posted by colemj

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]

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]

Originally Posted by Sid at SailAway

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.

[Cotemar]

Originally Posted by redsky49

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 it’s 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]

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]

Originally Posted by Celestialsailor

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]

I'm not doubting that your chain came off. Just wondering how.

[Bash]

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]

Originally Posted by Guy

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.