Anyone care to weigh in on whether or not 50' of chain equates to more than 50' of 3 strand when computing scope? For example, if the depth is 30' and you want to use 7:1, could you use 130' 3 strand + 50' of chain for the same holding power as 210' of all 3-strand? Or, is the only real advantage in the anti-abrasion quality of the chain vs rope?
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The chain is there to help maintain
a horizontal pull on the anchor. The seven to one scope keeps the pull at about 8 degrees above the horizontal when pulled taut. With heavy chain the chain will sag near the anchor with a 7:1 scope. All chain rode is often recommended for a 5:1 scope. I see no advantage in short scope anchoring.
a horizontal pull on the anchor. The seven to one scope keeps the pull at about 8 degrees above the horizontal when pulled taut. With heavy chain the chain will sag near the anchor with a 7:1 scope. All chain rode is often recommended for a 5:1 scope. I see no advantage in short scope anchoring.
good articles
There are many good articles on this subject. I recently read an excellent very technical article but I can't find it now -
. The bottom line for most of the techical analysis is that the chain does not necessarily help with any significant catenary and horizontal pull when you need it most - heavy winds and storm conditions. In fact, an all chain rode will not have any energy absorption and will possibly create more force to unset an anchor. the chain helps with initial setting and chafe protection. Here are some good articles (I'll still look for the best one): http://www.johnsboatstuff.com/Articles/anchor.htm http://www.bluemoment.com/anchorrodes.html http://www.tmca.nu/links.and.features/anchor.htm You should also consider the Yale Brait braided rope for your rode - it has more surface area than 3-strand for use in a windlass, stores more compactly, and has 10,400 lbs. working load (3/8" BBB chain has 3,600 lbs working load if I remember correctly), and it doesn't kink.
There are many good articles on this subject. I recently read an excellent very technical article but I can't find it now -
. The bottom line for most of the techical analysis is that the chain does not necessarily help with any significant catenary and horizontal pull when you need it most - heavy winds and storm conditions. In fact, an all chain rode will not have any energy absorption and will possibly create more force to unset an anchor. the chain helps with initial setting and chafe protection. Here are some good articles (I'll still look for the best one): http://www.johnsboatstuff.com/Articles/anchor.htm http://www.bluemoment.com/anchorrodes.html http://www.tmca.nu/links.and.features/anchor.htm You should also consider the Yale Brait braided rope for your rode - it has more surface area than 3-strand for use in a windlass, stores more compactly, and has 10,400 lbs. working load (3/8" BBB chain has 3,600 lbs working load if I remember correctly), and it doesn't kink.More articles - maybe mjb's 'best' one?
Here are 3 more links I've got on the subject of catenary and anchoring. For the mathematically inclined: http://alain.fraysse.free.fr/sail/rode/rode.htm Here's a page with a discussion of catenary - at the bottom is an Excel spreadsheet: http://www.johnsboatstuff.com/Articles/anchor.htm And Yale Cordage has a white paper on anchorning technology and techniques. Is it a surprise that they like their Brait? (I do too) http://www.yalecordage.com/html/pdf/anchoring_tech.pdf Read, study, mull it over and make up your own mind... I've found a lot of different opinions on the subject. My 2c (don't count this as an expert opinion by any stretch): If you're anchored in 'safe' conditions, the difference between 180' and 210' is trivial. If a storm is coming, you better let it ALL out, then work on where you want to place your spare anchor(s) and get cracking on chafe protection, etc. Cheers, Bob s/v X SAIL R 8
Here are 3 more links I've got on the subject of catenary and anchoring. For the mathematically inclined: http://alain.fraysse.free.fr/sail/rode/rode.htm Here's a page with a discussion of catenary - at the bottom is an Excel spreadsheet: http://www.johnsboatstuff.com/Articles/anchor.htm And Yale Cordage has a white paper on anchorning technology and techniques. Is it a surprise that they like their Brait? (I do too
) http://www.yalecordage.com/html/pdf/anchoring_tech.pdf Read, study, mull it over and make up your own mind... I've found a lot of different opinions on the subject. My 2c (don't count this as an expert opinion by any stretch): If you're anchored in 'safe' conditions, the difference between 180' and 210' is trivial. If a storm is coming, you better let it ALL out, then work on where you want to place your spare anchor(s) and get cracking on chafe protection, etc. Cheers, Bob s/v X SAIL R 8Thanks for links, Bob W and mjb
I don't plan to shorten scope but in crowded anchorages one does have to consider the neighbors. A common article you both linked discussed the advantages of chain/rope combos plus it had a very good link to a source for a kellet/sentinel. If I can't find one at the SF boat show this weekend, I'll order one from the stateside source. Anyway, good reading/infor. Thanks
I don't plan to shorten scope but in crowded anchorages one does have to consider the neighbors. A common article you both linked discussed the advantages of chain/rope combos plus it had a very good link to a source for a kellet/sentinel. If I can't find one at the SF boat show this weekend, I'll order one from the stateside source. Anyway, good reading/infor. Thanks
Don't spend much money on a Kellet/sentinel
They work well, but a cheap mushroom anchor tied to a carrabiner and a retrieval line works exactly the same way for a whole lot less money. Steve Alchemist C-320
They work well, but a cheap mushroom anchor tied to a carrabiner and a retrieval line works exactly the same way for a whole lot less money. Steve Alchemist C-320
Kellet Schmellet
Just find that half sack of concrete in the garage, mix it up in a plastic bucket, grab your kid's cable bicycle lock (since he left his bike at his friends house two years ago)tie it in a loop and stick half the loop it in the concrete. Knock the concrete out of the bucket in the morning and stick it in an old tee shirt so it doesn't bang up the deck. Voila, ze kellet !
Just find that half sack of concrete in the garage, mix it up in a plastic bucket, grab your kid's cable bicycle lock (since he left his bike at his friends house two years ago)tie it in a loop and stick half the loop it in the concrete. Knock the concrete out of the bucket in the morning and stick it in an old tee shirt so it doesn't bang up the deck. Voila, ze kellet !
I hope it's not much difference, Ross....
since I just ordered 50' of 1/4" Hi-test chain to replace my old, rusty hunk of 3/8" chain As I have no windlass other than my aging back, I'll live with the slightly reduced catenary. Kellets - I've read good and bad about them. From my research (but without any practical experience) I'd rather bulk up my anchor by 10 or 20 lbs and go with larger chain than worry about setting and retrieving a kellet. Jim, all rope or rope/chain is MUCH preferable to all chain for EVERY aspect of anchoring save 1.... underwater chafe. If you don't KNOW that your anchoring ground is clear EVERY TIME you drop your hook, you're going to HAVE to carry all chain.... or give up sleeping at anchor. I'm interested in some way to combine rope and chain with a float in the middle to keep the rope off the bottom.... still risky. Scott, my kids are grown, but I'll keep your 'scott schmellett' in mind ;D Cheers, Bob
since I just ordered 50' of 1/4" Hi-test chain to replace my old, rusty hunk of 3/8" chain
As I have no windlass other than my aging back, I'll live with the slightly reduced catenary. Kellets - I've read good and bad about them. From my research (but without any practical experience) I'd rather bulk up my anchor by 10 or 20 lbs and go with larger chain than worry about setting and retrieving a kellet. Jim, all rope or rope/chain is MUCH preferable to all chain for EVERY aspect of anchoring save 1.... underwater chafe. If you don't KNOW that your anchoring ground is clear EVERY TIME you drop your hook, you're going to HAVE to carry all chain.... or give up sleeping at anchor. I'm interested in some way to combine rope and chain with a float in the middle to keep the rope off the bottom.... still risky. Scott, my kids are grown, but I'll keep your 'scott schmellett' in mind ;D Cheers, BobA man's age in feet of chain? Wrong quote?
My 50' of 1/4" chain weighs about 35#.... 50' of 3/8" chain is about 85#. Difference of 50#.... Dang, there's my age again ;D Of course, you're only effectively lifting chain equal to the water depth plus the anchor. Mine is a 29# 'Bruce Lee', so even in 50' I'm only lifting about 65#, versus 114# with the bigger chain. I'll go with the smaller chain, and if I feel the need, I'll rig up a 'scott schmellett' ;D And my cruising boat (going to the big Oakland boat show, get to fondle a Hylas *5) is going to have a HUGE 'drop and forget' CQR or Bruce attached to 300' of large hi-test chain....oh, yeah, and an electric windlass to haul it all up with ;D Cheers, Bob s/v X SAIL R 8
My 50' of 1/4" chain weighs about 35#.... 50' of 3/8" chain is about 85#. Difference of 50#.... Dang, there's my age again ;D Of course, you're only effectively lifting chain equal to the water depth plus the anchor. Mine is a 29# 'Bruce Lee', so even in 50' I'm only lifting about 65#, versus 114# with the bigger chain. I'll go with the smaller chain, and if I feel the need, I'll rig up a 'scott schmellett' ;D And my cruising boat (going to the big Oakland boat show, get to fondle a Hylas *5) is going to have a HUGE 'drop and forget' CQR or Bruce attached to 300' of large hi-test chain....oh, yeah, and an electric windlass to haul it all up with ;D Cheers, Bob s/v X SAIL R 8
In deep water I lead the rode back to a
sheet winch and crank things in until the chain gets to the winch. Then I cleat the nylon and go forward for the rest. Kinda tough on the paint but fifty cents worth of new paint in the spring takes care of that.
sheet winch and crank things in until the chain gets to the winch. Then I cleat the nylon and go forward for the rest. Kinda tough on the paint but fifty cents worth of new paint in the spring takes care of that.
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