Considering switch to all chain rode

[R_C]

Originally Posted by RainDog

So it sounds like the only problem with your current setup is you want to use less scope?

Ideally we need some more information to answer your question. You say you rarely anchor in more than 15', what is the minimum you normally anchor in? Where and in what kind of conditions are you anchoring in? Sand only? Rock? Fair weather only?

I think the cheapest way to solve the scope problem would be to switch to a 45 lb next gen anchor and 75' of G4 chain. The new anchors (Manson Supreme, Mantus, etc.) seem to work better with less scope. You also may be able to go down a size and get the same holding power. This will make retrieval much easier. 75' of G4 will still be reasonable to pull up by hand but will give you all chain at 5-1 in 15' (plus 25' of nylon that will be backed up by a snubber. IMHO, this is the minimum amount of money that solves you stated problem without creating a new problem.

If you are anchoring in hurricanes or rock bottoms, maybe you should stick with a heavier anchor

That's correct, we would like to reduce the scope. With all chain its also reassuring that some numpty with a knife can't set our boat adrift. We anchor mostly in sand and mud and normally not less than 6' of water. While we try to find good protection for blows, we have been anchored in 20 to 30 knots.

Whenever I read a thread about anchor types it appears every poster believes theirs is the best anchor. Are the new anchors that much better than a claw (i.e. Bruce) in sand or mud?

Your calculation for 15' of water omits the 5' to the bow roller. So we'd really need 100' of chain at a 5:1 scope. I'm considering 125' of chain since 12' of water is a more likely maximum plus the 5' to the roller with the option to increase scope to 7:1.

[R_C]

Originally Posted by Stu Jackson

You're getting close. You need to size your anchoring SYSTEM. Like this:

Anchor System Sizing Tables (Reply #6) & Why Swivels are a bad idea Ground Tackle & Anchor System Sizing TABLES & Swivels


Good luck.

Thanks Stu. I had not seen an estimate of the load on the ground tackle based on the beam of the boat and wind. That is really useful information and much appreciated.

[transmitterdan]

Originally Posted by R_C

Whenever I read a thread about anchor types it appears every poster believes theirs is the best anchor. Are the new anchors that much better than a claw (i.e. Bruce) in sand or mud?

Yes. In mud nothing beats a big Fortress such as the FX-37. In sand there are at least 5 anchors better than a claw. If your boat cannot deal with a roll bar then the Spade is hands down the best anchor for sand.

Chain will not help you reduce scope. A good anchor well set in a good holding bottom will. Chain is popular mainly for its abrasion resistance not its ability to reduce scope. It is much heavier for a given strength than rope. A lot of people mistakenly believe that the chain being heavier improves the anchor's ability to hold. That is not true. All rodes whether rope or chain become straight when the wind is really up. So the benefit of catenary goes away when you would need it most. Also, chain is inelastic unlike nylon rode. So with chain a long nylon snubber helps to reduce shock loading.

If you truly want to reduce scope and sleep well then you need a new anchor.

[Lepke]

The book I was taught by (a long time ago) recommended 4:1 with chain and 7:1 for cable. Meaning old heavy ships cable. An that's assuming you are using a recommended chain size for the vessel. Both chain and heavy cable help keep the shank parallel to the bottom and keep even a poor anchor's flukes buried.
You can pull chain on a cathead. It might take the paint off. When I run 2 anchors, I use mine for the 2nd anchor. I've never had a chain break and when commercial fishing, I often anchored in ocean swells. Sometimes 10'+ swells. Bodega Bay is the last anchorage, going north, where you can sleep easy for a long way.

[ranger58sb]

RC, you can investigate typical scope settings recommended by various makers, and you may find some may not recommend 7:1. I know for our pivoting SuperMAX, they recommend about 5:1 scope for most circumstances... and even 4:1 in some situations with an all chain rode.


See here for example:
Max Marine Products - Why It Works


Probably other makers publish similar info.


85 feet of leading chain on a mixed rode would be 5:1 scope in 12' of water with your pulpit 5' off the surface... if that, coupled with a new anchor of some sort, might suit.


Incremental tweaks might lead you to an improved position. New anchor now, assess... improved rode later, assess... new windlass eventually, if necessary...


Just thinking about ways to think about the problem, much as you've done...


-Chris

[R_C]

I can understand how a better anchor could allow reducing scope but I'm reluctant to abandon what has worked well. The typical bottom in southwest FL where we anchor most is probably more a combination of sand and clay. In 10 years we dragged our claw once and that was due to an unexpected blow and insufficient scope.

Many sources including Chapman Piloting and anchor manufacturers list a shorter scope for all chain rode. I understand that when all chain and mixed chain and nylon rode are straight the affect on the anchor is the same. But what does it take to get all chain rode straight? Are there any tables that show how much wind is required to get the same length of nylon and chain rode straight? Or could that be easily calculated? Is the difference significant enough to justify the shorter scope for all chain?

[tinkrman69]

I'm a single hander with all chain rode. on a 42 ft ketch. I have a manual windless, which takes forever to haul in the rode. I pull it in by hand. in a good wind I take the time to wench it on the windless till its broke loose. then I haul it up by hand.

All chain doesn't necessarily mean less scope. a boat your size would pull an all chain rode straight in anything over 15 or so knots, Hence pulling the anchor out of the bottom. 5:1 scope is fine for lunch. Do the work and put out the extra scope, if not just for your own comport, for those around you, that you'll be hitting when you drag.

if you want to have a soft life, let your muscles atrophy and get weak. hire crew. Gadgets break at the most inopportune times and if you can't take up the slack, your screwed and lives may even be at stake. Don't get me wrong, some machinery is good. But, there is a line to be drawn. Watch the animated movie "Wall E" that's the future of the ones that don't want to do the manual part of life.

I have a friend on a 42 foot trawler. She goes up the coast through the lakes to canada, hikes 20 miles in to her cabin, does the repairs and stays for the summer then she comes down the rivers to south florida, single handed, as her partner passed several years ago. only uses dockage at either end of the trip. She's 70 this spring. She says "stay active, do the manual labor, eat well and your mind will stay clear and the body will feel good" I try my best to follow her Que.

[Ocean Girl]

Originally Posted by R_C

I can understand how a better anchor could allow reducing scope but I'm reluctant to abandon what has worked well. The typical bottom in southwest FL where we anchor most is probably more a combination of sand and clay. In 10 years we dragged our claw once and that was due to an unexpected blow and insufficient scope.

Many sources including Chapman Piloting and anchor manufacturers list a shorter scope for all chain rode. I understand that when all chain and mixed chain and nylon rode are straight the affect on the anchor is the same. But what does it take to get all chain rode straight? Are there any tables that show how much wind is required to get the same length of nylon and chain rode straight? Or could that be easily calculated? Is the difference significant enough to justify the shorter scope for all chain?

Fantastic questions. Not sure if you've read Even and Beth's write ups..

http://www.bethandevans.com/pdf/Main...hor%20test.pdf

Also Alain fraysse awesome page ....
Rode - Static Behavior

Hope this helps.
Erika

[Dave22q]

I think Raindog has a key point. Your problem seems to be that you want to reduce your scope from 7/1 to 5/1. Do you have any evidence that your current set up drags at less scope? If not I would first try to establish that I have a problem and then look for solutions. An upgraded anchor might be a better alternative. What kind of depth do you currently anchor in? I cannot see using a snubber unless you current rode in the water is mostly chain. If that is the case switching to all chain will accomplish nothing.

[Terra Nova]

Originally Posted by R_C

...Both the nylon rode and chafing line run over the bow roller then are wrapped a few turns around the captson and cleated to opposite bow cleats...

This is very bad practice. Take the loads off the windlass while anchored.

Switching to all chain will allow you to shorten scope. 5/16" G4 would seem a good choice for your boat. Terra Nova is 24,000 lbs and has 270' of 3/8" G4.

[Cheechako]

Huge improvement to all chain. Especially on your body! A lot of problems get aired on the internet that are very rare in the real world.

[tomfl]

My main anchor is a Manson Supreme with chain. Like most cat guys I always use a bridle and think even on a monohull that is important. Don't want to claim my setup is the best and I suggest you get input from mono guys about how to set up a bridle.

Not sure why this has not been mentioned yet as I see lots of monohulls using bridles.

[latka]

Originally Posted by zeehag

in many locales anchoring with mixed rode causes loss of boat., to me it seems that the price of all chain and a windlass is a lot less than replacing a boat.
but then i dislike the idea of finding my home on the rocks.
my bruce has , as primary anchor, 196 ft 5/16 chin, my secondary, 45 pound cqr, has 250 ft 5/16.

although i have 2 windlasses on my bows, i generally pick my anchor and rode off bottom by hand. i am an old woman, and i have never heard such whining from men who "cannot" lift anchors and chains off bottom of seafloor. and yes i pick up 150 ft asthat is what i use, even in 10 ft depth. wind happens.
drag queens are entertainment, not sailors

Can't agree more! I just survived a nasty blow, with bullets of 55 knts racing down the hills and boy was I glad to have all the chain I needed and the good ol' trusted plough in the mud. Once I knew the anchor had set properly I never had to go back onto the foredeck. However, guys next to me were checking every hour if their nylon rode was still healthy! And this lasted 40 hrs!
Can't say I slept well but I knew we were safe. And for me that's what matters most.

[captjcook]

If it is an older bronze Ideal vertical windlass...Ideal, at least last year, would convert it to include a gypsy/wildcat. Very well built and rebuildable units. This would save fiberglass work in changing out windlass. I have a bow eye installed about 6" above w/l with large backing plate to reduce vertical dip of about 4' (4x5=20) less scope, I run my 20' nylon snubber to it.

[nautical62]

Having had both all chain and mixed chain and rope rode, I much prefer all chain for the following reasons:

1. Less likely to get cut on anything sharp including coral.

2. Can use shorter scope or use the same scope with with more security in tighter anchorages.

3. Less likely to tangle around keel or prop shaft in places with currents, light shifting winds, etc.

4. I prefer deploying and retrieving a single rode over a mixed rode.