CHAIN

[simonhantler]

Originally Posted by -bliss-

I would strongly advice against SS anchor chain. Sure, it doesn´t stack as much as galvanized, but it doesn´t give you a warning before snapping either. (As we all know, stainless is brilliant on deck, but not so permanently submerged, deprived of the oxygen in the air.) The links in a galvanized chain on the other hand will not break without a warning, but stretch to the point where it will be very hard to make it fit the gypsy, which will give you plenty of time to replace before breaking.

Neither AISI 304 nor 316 SS will be nearly as strong as quality galvanized and would probably cost four times as much..

If your chain locker isn´t deep enough, my first thought on your behalf would be reconsider the need of 100 meters of chain. Sure, it would be nice on the very rare occation you could use it, but the rest of the time it´s a pain when it builds up in the locker and makes your gypsy jam.. Since you are a cat- owner, I assume you use a bridle snubber connected to the inside of the hulls quite close to the water line. This arrangement gives you a much better scope than us mono- owners who in addition to water depth, have to add the distance from the bow roller to water level x 5, in order to deploy the right scope..

In your shoes, I probably would have considered approximately 75 or 80 meters of chain spliced to a length of polyester octoplait. To be perfectly honest, I probably would skip the octoplait polyester rope and instead connect the chain to a 12 mm double braid dyneema line (dyneema core/polyeter cover.) After all, the only job for this rope would be retrieving the chain, as the bridle snubber should take the flexing while on the hook. This way you can connect the chain hook/ soft shackle/ rolling hitch at the end of your flexible snubber bridle almost to the end of the chain, and pay out as much as your snubber tolerates which still means you would have a very long chain + the length of the snubber bridle available + easily splicable, strong and chafe resistant dyneema line (with soft comfortable polyester cover) spliced to the chain for retrieving. This should easily give you approximately 85 or 90 meters of rode, which I assume would be more than enough for 98% of the time, depending on your cruising ground, of course. Clearly I don’t know your preferences or where you cruise, but just wanted to point you in a direction I find reasonable, given your vessels narrow chain locker. An obvious added bonus to a tad shorter chain is less weight, which I guess is a factor in your cat.

Personally I have a chain made by Maggi in Italy. It´s a grade 70 (or Aqua 7 as The Maggy Group call it) I have a very deep locker, so I had them make my chain 100 meters long, but have never used the whole length.. I also asked them to weld an oversized link in both ends in order to accommodate a high quality shackle with a bolt as big as possible. Comes handy in case the hook gest stuck and side loaded. The reason why I have the oversized links in both ends, is to be able so reverse the chain every second year or so to make sure the wear of the galvanizing is evenly distributed the whole 100 meters. Most of the time I deploy roughly 40- 50 meters, so reversing the chain every two years basically doubles the life expectancy of the chain. While reversing it, I also touch up the spray painted color codes every 10 meters, and replace the excellent Crosby G209A shackle. Probably not necessary, but cheap insurance anyway. After all, a good nights sleep is underrated.

The 10 mm Aqua 7 chain is 2,3 kg per meter, so by reducing from 100 to 80 meters, you save 46 kg/ roughly 100 pounds, which is almost the weight of your beefy Rocna.. The Aqua 7 is immensely strong, so anything over 10 mm seems way overkill in my opinion, even for a 15 ton cat. My chain happens to be only 8 mm (which weights 1,45 kg per meter) I´m not a racer, but I certainly don´t care for hobby horsing, so saving weight up front is imperial. Lighter stronger chain and a big heavy anchor seems the way to go. My 8 mm Grade 70 also takes up way less space in the chain locker than the rusty old chain it replaced. My mono is 20 tons fully loaded, and I never considered a thicker chain when it was time to replace. Personally I think the 8 mm should be more than sufficient for your 15 ton cat as well, but I understand this is controversial to the ones who believe in the catenary effect even in strong winds. I believe the catenary effect is real, but sadly it´s present only when you don’t need it, and absent when you need it, so in my opinion, the numbers for chain thickness and weight should be as low as possible to free up space and weight in the locker, not as high as possible to make the chain bounce in the waves.. When the wind pipes up, the chain quickly gets tight anyway..

Obviously, this is your own decision to make, I´m just sharing my philosophy, and telling that I´m satisfied with my choice after five seasons with this chain. The thin 8 mm definitely would have freed up a lot of space and weight in your locker though.. A long flexible snubber will eliminate shock loads on your chain, and adequate scope in a thin strong G70 chain would be the perfect combination to your tiny chain locker and massive Rocna in my opinion.

100 meters of 8 mm grade 70 weight 145 kg, and 100 meters of 10 mm weights 230 kg. The difference of 85 kg is considerable, not to mention your locker size limitations..

A little piece of advice regarding color codes is to paint the chain symmetric, to make sure the colors are the same before and after reversing the chain. My chain is coded like this:
10 m, red, 20m blue, 30m yellow, 40 m green, 50 m orange, 60 m green, 70 m yellow, 80 m blue and 90 m red. Works like a charm, even for a sleepwalker like me.

Enjoy the prosess of finding your perfect anchor chain!
Best regards,
-kjetil-

Disclaimer: I don´t work for maggi chain, and didnt recieve a discount of any kind. Just satisfied with the chain i bought. Customer support was pretty mediocre to be honest, but all that was forgotten when the beautiful custom made chain finally arrived.

Thanks kjetil. Great advice. Looks like I’ll go for 100 m of 10mm G7 Maggi. Or 70m with a dynema rode. Still haven’t built the boat yet, just working out changes to the design and what gear I’ll need to buy. There’s a local importer of Maggi chain here I’ll visit to get measurements of piled 100 vs 70m and build anchor chain locker accordingly.

[-bliss-]

My pleasure simonhantler. Glad to help!

Your local Maggi Chain distributor might get a quote from Italy regarding oversized end links in both ends.. (We all know the cliché regarding the weakest link of the chain, right..) With oversized end links you will be able to fit a bigger stronger shackle that will be just as strong (or possibly stronger) than the rest of the chain. Many here on the forum use the Crosby G209A.

If you haven’t seen it already, I´ll strongly suggest reading Noelex 77´s thread http://www.cruisersforum.com/forums/...ng-126073.html

Lots of well documented first and second hand experiences of anchor behavior, lots of beautiful underwater pictures and lots of educational information and reflections regarding all kinds of anchor gear. I´m forever grateful to Mr Noelex 77 and his wife for the time they invested to share their experiences. I have learned so much from this couple. Thank you both!

Good luck with the cat- build, simonhantler. Very exiting process ahead of you..

Best regards,
-kjetil-

[Benz]

Originally Posted by SundayMorning

bliss: "Since you are a cat- owner, I assume you use a bridle snubber connected to the inside of the hulls quite close to the water line. This arrangement gives you a much better scope than us mono- owners who in addition to water depth, have to add the distance from the bow roller to water level"


Not meaning to hijack the thread, but is there a reason that monos don't do the same? They use a snubber anyway. It could be permanently attached to a fitting at the bow near the water level and the hook end carried onboard when underway. When anchoring just attach the hook (or soft shackle) to the chain as it goes out, just like a bridle on a cat. Deploy enough chain to make the snubber take the load, like usual, just with the entire snubber now overboard.


If a center-bow fitting is not good for the fiberglass joint, fittings on each side could be attached to a mini-bridle. I've never seen it done on a mono, but it would allow shorter chain with the same scope as bliss mentioned.

Monos can do this, if they wish. I reeve a snubber line through a fairlead attached to my bobstay fitting. Keeps the angle down (essentially the rode joins the boat at the waterline), and nothing can chafe on the bobstay.
I suspect most monos don't have a bobstay fitting beefy enough or configured to this purpose--some monos don't even have a bowsprit, strangely enough!

[Benz]

Originally Posted by billknny

Then whoever "THEY" are, "THEY" are not people you should be listening to. There is no such thing as "high tensile" stainless.

There are lots of good reasons that stainless makes terrible chain for load critical applications in corrosive environments.

Bill,
Perhaps "high tensile" is not the official nomenclature for it, but surely you know that there are different alloys of stainless, and that some are stronger than others? Some, in fact, have a higher tensile strength than others due to their composition.
I would never have a stainless anchor chain, but there are varieties in stainless chain that we cannot deny.

[double u]

these krauts
https://www.ketten-waelder.com/produ...cromox-nautic/
came out far on top of everybody in a kraut sailing rag chaintest