Rappey
Well-Known Member
Hahaha.. Join the queue ! There are quite a few people that want my chain ! I have a SL seatiger 555. Am finding out a 8mm gypsy is rarer than the pink unicorns that roam my decks ?
Anchor chain: downsize from 10mm to 8mm?
- Thread starter Gary Fox
- Start date
Laminar Flow
Well-Known Member
Only because I was too cheap to invest in a new gipsy and it's what the boat came with.
The previous one, so terribly under-equipped by your standards, I co-designed and built and sailed halfway around the world. The times I went into port rather than anchoring out, after leaving Europe, I can count on a crippled hand. This includes riding out several blows over 50kts and enough in 40 kts that I lost count.
The amount of rubbish that is sometimes posted on this forum is astonishing.
I really goes both ways and I have come to understand that contemporary design is impervious to the perils of the sea, while delivering scintillating performance, even when fully loaded, while, on the other hand, those terrified by the very same perils, follow some nebulous sense of "instinct" and insist that it must be a long keel and then proceed to load half a ton of gear into the pointy end to destroy any last vestiges of sailing ability, just to prove "the other side" right.
Laminar Flow
Well-Known Member
Recommendations of Germanic LLoyd: Chain to DIN 766 according to displacement of boat
7-14t 8mm
15-20t 9mm
20-30t 10mm
7-14t 8mm
15-20t 9mm
20-30t 10mm
Gary Fox
N/A
9mm?
Would that be the Heckler and Koch chain, or the Luger?Nothing about it on Jimmy Green..
Gary Fox
N/A
Joking aside, you could use the gyppo off another make, eg Lofrans, and get it bored out and a suitable keyway cut, by any small engineering company. £100 probly.
Rappey
Well-Known Member
Ok, maybe 100, and another 150 for a gypsy plus whatever else and it soon starts adding up, or maybe i just put the 10mm on to my current anchor and job done...
I hardlt ever anchor anyway as i get the bloody things stuck.. An anchorage full of boats, they all leave at the end of the weekend and im left stuck again... grrr...
I swear i had 100m to start with but after nearly 30 years of having to saw anchors off ive about 10 metres left
.Good job they have been cheap anchors..
Tintin
Well-Known Member
I reckon Brunel had the right idea.
You nailed it with Bahamian moor - so 400m of 20mm - I'll go with that as a minimum.
Laminar Flow
Well-Known Member
You may have forgotten the recommendation to use a chum as well. To keep things in proportion: a couple of half ton mooring blocks to round off the ensemble should do it, easily stored, for ready use, on the submerged foredeck.
Neeves
Well-Known Member
No-one has commented on the 42 knots and 4,000lbs tension of the ABYC data.
Call 4000lbs - 2t. At that tension an 8mm chain will start to yield, stretch and most, 3/8th" shackles used by owners will start to bend. 42 knots is not that unusual and many have been subject to higher wind speeds. No-one has recorded that their chain stretched nor their shackles bent such that they had to cut the shackle off and abandon the chain. When I look at some bow rollers on modern AWBs particular those that lift over and or protrude I would be suprised if the device would withstand 2t, especially if side loaded. Many windlass installations I see, flimsy fibreglass base and 4 wimpy stainless bolts. I'm not entirely blaming the boat builder as 8mm chain has a WLL, commonly, of 750kg (G30) and unusually (though growing use) 1t (G40) and maybe they take these WLL as being the limit and actually well beyond the limit of use of bow roller and windlass.
I have measured tensions of 650kg - and the conditions on board are, at best, scary. I abandoned the measuring as simply being too robust. But the idea that you and your crew are sitting playing scrabble with a tension of, only, 2t is a joke. Most of the crew will be hysterical and those are not would be telling the skipper in no uncertain terms that they will never sail with him again nor be living with him in the future.
As someone else mention - your worries are only starting as at that tension and at that windspeed your own anchor might drag and the anchor of some of your neighbours will drag. Again because your anchor is likely to drag - the boat builder has it right. (Ours is a 38' x 7t cat (similar windage, roughly to a 45' x12t Bav, we use 6mm HT chain and 30m snubbers 2 off for a bridle - though our ground tackle is based on testing and collecting and collating data - it has been tested in real life).
As an aside - most people have no idea what the limits, in terms of strength, of their tackle, they don't know the hold of their anchor, they don't know the strength of their chain - because they never ask to see a test certificate. They have no idea of the actual tension in their rode.
The comment was made that snubbers fail. I think you will find I advocate carrying spares and the way I suggest a a snubber be installed and deployed it can act as a storm snubber (because it can be easily extended), and separately does allow for use of a storm snubber. Oddly the ABYC mentioned snubbers and snubber failure but assumes people don't carry spares nor storm snubbers. Snubbers do fail - partially because the hooks sold in chandlers are totally inadequate - and do bend. Again I recommend use of devices, 'hooks' from the lifting industry which are matched to the strength of the chain (or stronger)
Part of the trend of this thread is to deploying inordinate lengths of chain - this assumes that there is room to deploy a lot of chain - and if we are looking at worst case scenarios then you have to assume there will not be room to deploy beyond 5:1 - and your strategy (if you are planning for the ABYC disaster scenario), must, incorporate anchoring with a short rode - and then you lose catenary (which can only be replaced by a chum (I shudder) or snubber(s).
The recent storm through the Scillies underlines the issues - the storm was well forecast and the sensible moved out of harms way - by sailing to shelter. The ones that remained - many ended up on the rocks and were rescued by helicopter. The post mortem is not clear - but many simply dragged their anchors.
Our philosophy is very simple - bragging tights don't count. Listen to the forecast at breakfast and dinner - take heed - and if winds beyond 40 knots are forecast assume they will be higher and move to somewhere that is not going to be subject to 40 knots (or higher). The last time we had a 70 knot forecast we sailed 24nm to a more sheltered location and suffered winds of around 20 knots. Call us wimps, but we did not drag, there were no divorce proceedings and nothing broke (I don't recall if we played scrabble
).
Anchor threads seem designed to engender fear and develop to disaster scenarios where all the recommendations are for tackle for yachts much, much larger. Seldom do people mention the use of forecast and how listening should become second nature. Seldom do people advocate moving out of harms way (commonly saying there is no better shelter). Storms are very well forecast plenty of time to sail 100nm - it is difficult to believe there is no better shelter within 100nm. People don't have adequate snubbers, people don't have spare snubbers, people don't carry storm snubbers, people insist on using shackles that are perfect for your pet dog but have no place on a yacht. And the reality is. - most people don't endure a 42 knot wind - they do listen to the forecast, stay at home and mow the lawn (and play scrabble in the quiet of the evening with the children). If you are a live aboard you will know better - you will have moved to more shelter and you will have engaged your storm snubber. You will also have removed the furled headsails, Bimini etc and taken the dinghy off the bow.......and if appropriate you will have deployed your second anchor. You know it makes sense.
Anchoring is meant to be a pleasure - its is not part of an SAS course. Plan for the worst - have that storm snubber on board, carry a spare 'good' anchor and spare rode - and hope you get it right and never, ever, need to use any of it (in the same way you are never going to use your LJs , liferaft, flares, EPIRB etc.). AND listen to the forecasts.
Take care, stay safe
Jonathan
Call 4000lbs - 2t. At that tension an 8mm chain will start to yield, stretch and most, 3/8th" shackles used by owners will start to bend. 42 knots is not that unusual and many have been subject to higher wind speeds. No-one has recorded that their chain stretched nor their shackles bent such that they had to cut the shackle off and abandon the chain. When I look at some bow rollers on modern AWBs particular those that lift over and or protrude I would be suprised if the device would withstand 2t, especially if side loaded. Many windlass installations I see, flimsy fibreglass base and 4 wimpy stainless bolts. I'm not entirely blaming the boat builder as 8mm chain has a WLL, commonly, of 750kg (G30) and unusually (though growing use) 1t (G40) and maybe they take these WLL as being the limit and actually well beyond the limit of use of bow roller and windlass.
I have measured tensions of 650kg - and the conditions on board are, at best, scary. I abandoned the measuring as simply being too robust. But the idea that you and your crew are sitting playing scrabble with a tension of, only, 2t is a joke. Most of the crew will be hysterical and those are not would be telling the skipper in no uncertain terms that they will never sail with him again nor be living with him in the future.
As someone else mention - your worries are only starting as at that tension and at that windspeed your own anchor might drag and the anchor of some of your neighbours will drag. Again because your anchor is likely to drag - the boat builder has it right. (Ours is a 38' x 7t cat (similar windage, roughly to a 45' x12t Bav, we use 6mm HT chain and 30m snubbers 2 off for a bridle - though our ground tackle is based on testing and collecting and collating data - it has been tested in real life).
As an aside - most people have no idea what the limits, in terms of strength, of their tackle, they don't know the hold of their anchor, they don't know the strength of their chain - because they never ask to see a test certificate. They have no idea of the actual tension in their rode.
The comment was made that snubbers fail. I think you will find I advocate carrying spares and the way I suggest a a snubber be installed and deployed it can act as a storm snubber (because it can be easily extended), and separately does allow for use of a storm snubber. Oddly the ABYC mentioned snubbers and snubber failure but assumes people don't carry spares nor storm snubbers. Snubbers do fail - partially because the hooks sold in chandlers are totally inadequate - and do bend. Again I recommend use of devices, 'hooks' from the lifting industry which are matched to the strength of the chain (or stronger)
Part of the trend of this thread is to deploying inordinate lengths of chain - this assumes that there is room to deploy a lot of chain - and if we are looking at worst case scenarios then you have to assume there will not be room to deploy beyond 5:1 - and your strategy (if you are planning for the ABYC disaster scenario), must, incorporate anchoring with a short rode - and then you lose catenary (which can only be replaced by a chum (I shudder) or snubber(s).
The recent storm through the Scillies underlines the issues - the storm was well forecast and the sensible moved out of harms way - by sailing to shelter. The ones that remained - many ended up on the rocks and were rescued by helicopter. The post mortem is not clear - but many simply dragged their anchors.
Our philosophy is very simple - bragging tights don't count. Listen to the forecast at breakfast and dinner - take heed - and if winds beyond 40 knots are forecast assume they will be higher and move to somewhere that is not going to be subject to 40 knots (or higher). The last time we had a 70 knot forecast we sailed 24nm to a more sheltered location and suffered winds of around 20 knots. Call us wimps, but we did not drag, there were no divorce proceedings and nothing broke (I don't recall if we played scrabble
).Anchor threads seem designed to engender fear and develop to disaster scenarios where all the recommendations are for tackle for yachts much, much larger. Seldom do people mention the use of forecast and how listening should become second nature. Seldom do people advocate moving out of harms way (commonly saying there is no better shelter). Storms are very well forecast plenty of time to sail 100nm - it is difficult to believe there is no better shelter within 100nm. People don't have adequate snubbers, people don't have spare snubbers, people don't carry storm snubbers, people insist on using shackles that are perfect for your pet dog but have no place on a yacht. And the reality is. - most people don't endure a 42 knot wind - they do listen to the forecast, stay at home and mow the lawn (and play scrabble in the quiet of the evening with the children). If you are a live aboard you will know better - you will have moved to more shelter and you will have engaged your storm snubber. You will also have removed the furled headsails, Bimini etc and taken the dinghy off the bow.......and if appropriate you will have deployed your second anchor. You know it makes sense.
Anchoring is meant to be a pleasure - its is not part of an SAS course. Plan for the worst - have that storm snubber on board, carry a spare 'good' anchor and spare rode - and hope you get it right and never, ever, need to use any of it (in the same way you are never going to use your LJs , liferaft, flares, EPIRB etc.). AND listen to the forecasts.
Take care, stay safe
Jonathan
Last edited:
Laminar Flow
Well-Known Member
You sure know how to ruin a perfectly entertaining thread by being way too realistic and reasonable.No-one has commented on the 42 knots and 4,000lbs tension of the ABYC data.
Call 4000lbs - 2t. At that tension an 8mm chain will start to yield, stretch and most, 3/8th" shackles used by owners will start to bend. 42 knots is not that unusual and many have been subject to higher wind speeds. No-one has recorded that their chain stretched nor their shackles bent such that they had to cut the shackle off and abandon the chain. When I look at some bow rollers on modern AWBs particular those that lift over and or protrude I would be suprised if the device would withstand 2t, especially if side loaded. Many windlass installations I see, flimsy fibreglass base and 4 wimpy stainless bolts. I'm not entirely blaming the boat builder as 8mm chain has a WLL, commonly, of 750kg (G30) and unusually (though growing use) 1t (G40) and maybe they take these WLL as being the limit and actually well beyond the limit of use of bow roller and windlass.
I have measured tensions of 650kg - and the conditions on board are, at best, scary. I abandoned the measuring as simply being too robust. But the idea that you and your crew are sitting playing scrabble with a tension of, only, 2t is a joke. Most of the crew will be hysterical and those are not would be telling the skipper in no uncertain terms that they will never sail with him again nor be living with him in the future.
As someone else mention - your worries are only starting as at that tension and at that windspeed your own anchor might drag and the anchor of some of your neighbours will drag. Again because your anchor is likely to drag - the boat builder has it right. (This is a 38' x 7t cat (similar windage, roughly to a 45' x12t Bav).
The comment was made that snubbers fail. I think you will find I advocate carrying spares and the way I suggest a a snubber be installed and deployed it can act as a storm snubber (because it can be easily extended), and separately does allow for use of a storm snubber. Oddly the ABYC mentioned snubbers and snubber failure but assumes people don't carry spares nor storm snubbers. Snubbers do fail - partially because the hooks sold in chandlers are totally inadequate - and do bend. Again I recommend use of devices from the lifting industry which are matched to the strength of the chain (or stronger)
Part of the trend of this thread is to deploying inordinate lengths of chain - this assumes that there is room to deploy a lot of chain - and if we are looking at worst case scenarios then you have to assume there will mot be room to deploy beyond 5:1 - and your strategy (if you are planning for the ABYC disaster scenario), must, incorporate anchoring with a short rode - and then you lose catenary (which can only be replaced by a chum (I shudder) or snubber(s).
The recent storm through the Scillies underlines the issues - the storm was well forecast and the sensible moved out of harms way - by sailing to shelter. The ones that remained - many ended up on the rocks and were rescued by helicopter. The post mortem is not clear - but many simply dragged their anchors.
Our philosophy is very simple - bragging tights don't count. Listen to the forecast at breakfast and dinner - take heed - and if winds beyond 40 knots are forecast assume they will be higher and move to somewhere that is not going to be subject to 40 knots (or higher). The last time we had a 70 knot forecast we sailed 24nm to a more sheltered location and suffered winds of around 20 knots. Call us wimps, but we did not drag, there were no divorce proceedings and nothing broke (I don't recall if we played scrabble
Anchor threads seem designed to engender fear and develop to disaster scenarios where all the recommendations are for tackle for yachts much, much larger. Seldom do people mention the use of forecast and how listening should become second nature. Seldom do people advocate moving out of harms way (commonly saying there is no better shelter). People don't have adequate snubbers, people don't have spare snubbers, people don't carry storm snubbers, people insist on using shackles that are perfect for your pet dog but have no place on a yacht. And the reality is. - most people don't endure a 42 knot wind - they do listen to the forecast, stay at home and mow the lawn (and play scrabble in the quiet of the evening with the children). If you are a live aboard you will know better - you will have moved to more shelter and you will have engaged your storm snubber. You will also have removed the furled headsails, Bimini etc and taken the dinghy off the bow.......and if appropriate you will have deployed your second anchor. You know it makes sense.
Anchoring is meant to be a pleasure - its is not part of an SAS course. Plan for the worst - have that storm snubber on board, carry a spare 'good' anchor and spare rode - and hope you get it right and never, ever, need to use any of it (in the same way you are never going to use your LJs , liferaft, flares, EPIRB etc.). AND listen to the forecasts.
Take care, stay safe
Jonathan
Neeves
Well-Known Member
Sorry. - it might be Spring here but its not called April - we still call this month September, mind you - with Covid - a September like no other.
The thread became increasingly more bizarre, you cannot make it up - the trouble is people believe some of this stuff and the fear is the author's also believe it.
I'm not used to some of the chain sizes quoted but had to smile when I worked out that the rode being recommended for a 12t yacht was 500kg. I decided not to investigate the the size of windlass needed for all of this as I would need to then look at the battery capacity to power it all, then the alternator to recharge - weight in the bow became a minor issue. I was going to query the size of the 'chum' being recommended - but then saw Laminar's estimation - it all became bigger than our mooring.
Put me down as a killjoy - defeated by the unusual and futile investigation with which I could not cope.
Makes 'bigger is better' almost acceptable
Jonathan
Edit - when I'm unreasonable I get wrapped across the knuckles - must be careful.
The thread became increasingly more bizarre, you cannot make it up - the trouble is people believe some of this stuff and the fear is the author's also believe it.
I'm not used to some of the chain sizes quoted but had to smile when I worked out that the rode being recommended for a 12t yacht was 500kg. I decided not to investigate the the size of windlass needed for all of this as I would need to then look at the battery capacity to power it all, then the alternator to recharge - weight in the bow became a minor issue. I was going to query the size of the 'chum' being recommended - but then saw Laminar's estimation - it all became bigger than our mooring.
Put me down as a killjoy - defeated by the unusual and futile investigation with which I could not cope.
Makes 'bigger is better' almost acceptable
Jonathan
Edit - when I'm unreasonable I get wrapped across the knuckles - must be careful.
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Wandering Star
Well-Known Member
Using your rule of thumb, I’m looking for a supplier of 2mm chain for my Sadler 25.
[2574]
...
But one useful thing came to me from your utter reasonableness....chain hooks. The standard 8mm jobby from Jimmy Green and suchlike seems to have a rated load of one tonne which is pretty hopeless on g70 8mm with a break load of 7t. So I've looked at lifting grade hooks and found an 8mm galvanised hook with a 9t break rating. Cost? £2.03 + Vat versus £12 for the SS Jimmy Green jobby. One really wouldn't want a chain hook to fail whilst enduring a blow, could have unpleasant and expensive consequences as one's windlass explodes. So, order for multiple lifting grade chain hooks going in this morning.....and on it goes.....Sorry. - it might be Spring here but its not called April - we still call this month September, mind you - with Covid - a September like no other.
The thread became increasingly more bizarre, you cannot make it up - the trouble is people believe some of this stuff and the fear is the author's also believe it.
I'm not used to some of the chain sizes quoted but had to smile when I worked out that the rode being recommended for a 12t yacht was 500kg. I decided not to investigate the the size of windlass needed for all of this as I would need to then look at the battery capacity to power it all, then the alternator to recharge - weight in the bow became a minor issue. I was going to query the size of the 'chum' being recommended - but then saw Laminar's estimation - it all became bigger than our mooring.
Put me down as a killjoy - defeated by the unusual and futile investigation with which I could not cope.
Makes 'bigger is better' almost acceptable
Jonathan
Edit - when I'm unreasonable I get wrapped across the knuckles - must be careful.
stranded
Well-Known Member
Which supplier please?
[2574]
...
stranded
Well-Known Member
Cheers.
Lightwave395
Well-Known Member
I have a relatively light weight (less than 8T nowadays in cruising mode) 12M 'cruiser/racer which has over the past few years been made more 'cruiserly'.
If I carried anything like the size and amount of chain mentioned in some of the foregoing posts my major problem would be keeping the prop or rudder in the water when sailing or motoring.
I guess its not really a problem for me as we don't anchor for very long periods and in the event of bad weather my boat is better being sailed than heaving to.
As an ex-racer turned cruiser I confess to still having a distinct aversion to carrying loads of weight, particularly at the front of the boat.
I'm on a mooring this summer for the first time and the yard gave me a 12mm chain strop, that won't even run through the miserly bow roller I have so for whats left of this summer I have a 30mm rope snubber attached to the chain when I leave the boat, which has ridden out the couple of strong wind sessions there have been in the South West.
They're going to fit me an 8mm strop for next season, same as my anchor chain (of which I carry a modest 25M...) but I'll still use a snubber
Oh and there's not really room for an electric windass but regular anchoring does save me a gym subscription...
If I carried anything like the size and amount of chain mentioned in some of the foregoing posts my major problem would be keeping the prop or rudder in the water when sailing or motoring.
I guess its not really a problem for me as we don't anchor for very long periods and in the event of bad weather my boat is better being sailed than heaving to.
As an ex-racer turned cruiser I confess to still having a distinct aversion to carrying loads of weight, particularly at the front of the boat.
I'm on a mooring this summer for the first time and the yard gave me a 12mm chain strop, that won't even run through the miserly bow roller I have so for whats left of this summer I have a 30mm rope snubber attached to the chain when I leave the boat, which has ridden out the couple of strong wind sessions there have been in the South West.
They're going to fit me an 8mm strop for next season, same as my anchor chain (of which I carry a modest 25M...) but I'll still use a snubber
Oh and there's not really room for an electric windass but regular anchoring does save me a gym subscription...
Neeves
Well-Known Member
You highlight a problem of G70 chain. it is very difficult to source compatible components, that fit and are stronger than the chain. I wanted a high tensile chain and set out to develop an answer to the problem - all of which relies on borrowing from the lifting industry. My chain accepts Grade B shackles, has a HT hook (in my case bridle plate, see below) and has enlarged links to accept the shackle. I also make an anchor righter, instead of a swivel, and it (Boomerang) also matches. So instead of faffing round sourcing bits and pieces from obscure locations people here in Oz (no wonder its called the Lucky Country) can source a complete High Tensile rode, individually and independently certificated for strength and for the thickness of the gal - gal determines chain life) - and the chain matches a boring and standard metric gypsy.
Marine lifting hooks, the ones from chandlers, do fail - I read of a Witchard hook failing, it bent and the chain fell out, not unusual. And Witchard hooks are not cheap (or not here)
I hope to do better and be of service
One of the complaints of industrial chain hooks and some hooks from chandlers is that if you have a decent snubber extended from the bow and then the wind drops - your snubber, hook and chain are pulled across the seabed and the hook falls off the chain. iIf you followed the article in the July issue of YM - this does not need to happen
But:
The hook top left is a typical chandler hook, The other three hooks are lifting hook and the hook top right is 'state of the art'. I have my hooks galvanised, along with the chains.
These hooks are clevis hooks apart from the bottom left which is an eye hook, where you can practise your skills with rope (but don't bother if you are, sensibly, using climbing rope - your skills are wasted you cannot splice climbing rope (try sewing the eye, use braided dyneema fishing line and patience)
But I digress.
Note that using the clevis in the stainless hook I have made a little stainless gate that lock the hook onto the chain. You need to get the fit 'just right' and then you can apply the slightest pressure of the thumb of the hand holding the hook and swing open or lock the gate. The hook top right I have tapped (before galvanising), used a pan head Alan recessed bolt to secure a small piece of fibreglass to make the gate. For the stainless hook you may need to buy a new slightly longer clevis to accept the thickness of the stainless gate you have made. The gate does not need to be stainless a robust polymer will do. Some chandler hooks come with a pin to secure the hook to the chain. The pin is a liability - they bend with ease and can bend in use - and then you cannot release the hook from the chain (unless you happen to have a Mole wrench handy). Been there, done that - without the Mole handy!
The pins on lifting hooks have the same fault. You can replace the pins - its a bit of a faff, use wire (of the appropriate size) from a bicycle wheel (a spoke) its a hard drawn steel and does not bend easily. You can make a little handle, or loop, to allow you to attach a pull cord). To secure the pin fill the hole with Sika and as the Sika sets off - rotate the pin. You end up wth a Size filled hole - sufficient to stop the pin falling out. You do need to replace periodically.
If you look at the stainless hook - its pretty crude and unacceptable for lifting. It has a sharp edge on the interior of the jaw - which if nothing else will damage the galvanising. The other hooks all have a saddle on which the link in the jaw is supported and the 'lips' of the jaw are concave to accept the appropriate adjacent link. So the load is taken by the link in the jaw and its adjacent link. If you look at most hooks in chandlers - they have that sharp ridge on the interior, or working surface of the jaw.
The lifting industry point out that their hooks do not reduce chain strength, unlike the stainless hook, and the lifting hooks can be used and failure of the chain will not be at the hook. I tested chain in a standard chandler hook - it reduced the strength of the chain (article in Practical Sailor).
Lifting hooks cost peanuts - the clever trick is find lifting hooks that are galvanised.
I have not found a simple way to make a gate for the eye hook
This our bridle plate - Our bicycle spoke retaining pin is bottom left and I have had time on my hands, tapped the pin and added a small handle.
For those of you that have followed my threads - you maybe recall one on LFRs - these are the LFRs in use - thanks to all who contributed to that thread. The plate is Duplex stainless (bizarrely painted black - another loss in translation
) and the LFRs are 2 part, threaded x 316 stainless. And that's's our high tensile 6mm rode. If you want the story on the Bridle plate send me a PM with you email address and I'll send you a pdf. I, unsurprisingly, have a pdf on our 6mm chain development.Take care, stay safe
Jonathan
Neeves
Well-Known Member
We raced and cruised (camped in) a X-99 and I considered a X-119 (I'm showing my age) but also a LW395. We then sold our business, moved to Oz and bought a cat - the rest is history.
I sympathise
Jonathan
[2574]
...
You highlight a problem of G70 chain. it is very difficult to source compatible components, that fit and are stronger than the chain. I wanted a high tensile chain and set out to develop an answer to the problem - all of which relies on borrowing from the lifting industry. My chain accepts Grade B shackles, has a HT hook (in my case bridle plate, see below) and has enlarged links to accept the shackle. I also make an anchor righter, instead of a swivel, and it (Boomerang) also matches. So instead of faffing round sourcing bits and pieces from obscure locations people here in Oz (no wonder its called the Lucky Country) can source a complete High Tensile rode, individually and independently certificated for strength and for the thickness of the gal - gal determines chain life) - and the chain matches a boring and standard metric gypsy.
Marine lifting hooks, the ones from chandlers, do fail - I read of a Witchard hook failing, it bent and the chain fell out, not unusual. And Witchard hooks are not cheap (or not here)
I hope to do better and be of service
One of the complaints of industrial chain hooks and some hooks from chandlers is that if you have a decent snubber extended from the bow and then the wind drops - your snubber, hook and chain are pulled across the seabed and the hook falls off the chain. iIf you followed the article in the July issue of YM - this does not need to happen
But:
The hook top left is a typical chandler hook, The other three hooks are lifting hook and the hook top right is 'state of the art'. I have my hooks galvanised, along with the chains.
These hooks are clevis hooks apart from the bottom left which is an eye hook, where you can practise your skills with rope (but don't bother if you are, sensibly, using climbing rope - your skills are wasted you cannot splice climbing rope (try sewing the eye, use braided dyneema fishing line and patience)
But I digress.
Note that using the clevis in the stainless hook I have made a little stainless gate that lock the hook onto the chain. You need to get the fit 'just right' and then you can apply the slightest pressure of the thumb of the hand holding the hook and swing open or lock the gate. The hook top right I have tapped (before galvanising), used a pan head Alan recessed bolt to secure a small piece of fibreglass to make the gate. For the stainless hook you may need to buy a new slightly longer clevis to accept the thickness of the stainless gate you have made. The gate does not need to be stainless a robust polymer will do. Some chandler hooks come with a pin to secure the hook to the chain. The pin is a liability - they bend with ease and can bend in use - and then you cannot release the hook from the chain (unless you happen to have a Mole wrench handy). Been there, done that - without the Mole handy!
View attachment 121915
If you look at the stainless hook - its pretty crude and unacceptable for lifting. It has a sharp edge on the interior of the jaw - which if nothing else will damage the galvanising. The other hooks all have a saddle on which the link in the jaw is supported and the 'lips' of the jaw are concave to accept the appropriate adjacent link. So the load is taken by the link in the jaw and its adjacent link. If you look at most hooks in chandlers - they have that sharp ridge on the interior, or working surface of the jaw.
The lifting industry point out that their hooks do not reduce chain strength, unlike the stainless hook, and the lifting hooks can be used and failure of the chain will not be at the hook. I tested chain in a standard chandler hook - it reduced the strength of the chain (article in Practical Sailor).
Lifting hooks cost peanuts - the clever trick is find lifting hooks that are galvanised.
I have not found a simple way to make a gate for the eye hook
This our bridle plate - Our bicycle spoke retaining pin is bottom left and I have had time on my hands, tapped the pin and added a small handle.
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For those of you that have followed my threads - you maybe recall one on LFRs - these are the LFRs in use - thanks to all who contributed to that thread. The plate is Duplex stainless (bizarrely painted black - another loss in translation
Take care, stay safe
Jonathan
Interesting and surprising that the obvious need for a hook gate is not designed in to the hooks. I’m wondering whether a small cable tie wouldn’t be a solution to hold the hook on the chain, just snip it off when it comes up to the roller. Remembering that whilst the US spent $$$$$$ on designing a biro that worked in space the USSR gave their cosmonauts a pencil…….