Anchor sizing questions

[Excalibur5]

You're right. The chain is 5/16", nylon is 5/8". I mistyped.

Originally Posted by Training Wheels

Holy cow! 37’, 7 ton cat with 5/8” chain! Must be a helluva windlass.

[Jim Cate]

Twenty pounds more or less in the anchor weight makes no perceptible difference in retrieval if using a powered windlass, and damn little with a manual one (or using a deck winch when the windlass has failed). Equally, that small increment in bow weight will not be significant in pitching in a seaway.

However, when forced by circumstances to anchor on shorter scope than desirable or in bottoms with questionable holding, the larger anchor will indeed give greater security.

So I agree with Mike and others that say use the largest anchor that fits on the bow, and all chain rode as well. I'm also of the school that has experienced the damping effects of heavy chain, and prefer to use such. If the weight increment of the chain (much larger figure than the anchor weight difference) is a significant factor for your boat, then lighter, higher strength chain would make sense.

I suspect that most of those decrying the larger anchor don't spend much time anchoring in strange (to them) places. When one knows little about a new anchorage, the extra holding power of the big anchor and heavy chain is a comforting (and perhaps boat-saving) factor.

Jim

[chowdan]

Originally Posted by Jim Cate

Twenty pounds more or less in the anchor weight makes no perceptible difference in retrieval if using a powered windlass, and damn little with a manual one (or using a deck winch when the windlass has failed). Equally, that small increment in bow weight will not be significant in pitching in a seaway.

However, when forced by circumstances to anchor on shorter scope than desirable or in bottoms with questionable holding, the larger anchor will indeed give greater security.

So I agree with Mike and others that say use the largest anchor that fits on the bow, and all chain rode as well. I'm also of the school that has experienced the damping effects of heavy chain, and prefer to use such. If the weight increment of the chain (much larger figure than the anchor weight difference) is a significant factor for your boat, then lighter, higher strength chain would make sense.

I suspect that most of those decrying the larger anchor don't spend much time anchoring in strange (to them) places. When one knows little about a new anchorage, the extra holding power of the big anchor and heavy chain is a comforting (and perhaps boat-saving) factor.

Jim

Thanks for the detailed response! I am going to be going with an electric windlass, although which one is still on the drawing board.

It's a huge expense and I'd rather buy once and not have to buy again due to inadequate performance or size. I need to figure out how much room I have to work with on my now roller as you pointed out. Definitely something I didnt think about. I was thinking I'd be going with 200ft of chain and 100-200ft of 3 strand nylon rode.

I have always believed that one should take the size manufacturer's recommend and go the next size up. Granted I've never cruised, and when I spent a lot of time on the water, it was only anchoring for the day, so setting a deep hook wasnt as important.

I do believe that the newer anchors are better than old gen, though I'm not trying to create a debate of what's better. Just my personal belief, and since I'm getting everything new, I determined I should just go for the newer gen(though maybe something other than rocna).


I appreciate comments from all, it has actually helped me think things through. I have been considering an older gen anchor such as a delta so I can afford a bigger windlass. I need to spend a bit more time thinking about how I'll mount my windlass as I have a removable deck lid with about 6 inches of room between the hatch and a glassed in plate, then below that is where my chain Is stored.

I'll post some photos shortly for people to see and maybe someone can give insight to how they'd go about installing a windlass.

[billknny]

Originally Posted by donradcliffe

I think posters on anchor threads should be required to include the number of nights they have spent at anchor. After 5,000 nights on the hook, I'd go with the bigger Rocna and all 5/16 HT chain.

We spend at least 200 nights a year on the hook, in probably 100 different places.

What ^^^^ donradcliffe says.

Bigger anchor for better holding, chain for easy of handling and chafe proofing. Use the smallest high-test chain that is strong enough.


Nobody EVER woke up at 2AM, when the storm starts blowing, worried their anchor was too big.

The suggestion that you should size your ground tackle based on if you could lift it by hand... Really???

Every electric windlass that should be considered for a cruising boat should have SOME way of operating manually. Maybe not something you need often, but it should work. Even lacking that, your boat has winches. A rolling hitch and a couple lengths of line and you can pull anything up. Limiting the size of your anchor by such a criteria is just goofy.

[boom23]

I've been boating for over 25 years and I almost always anchor. I spent 3 years cruising the S. Pacific and New Zealand, where the weather can be very interesting.

I would get the biggest, newer generation anchor, you can handle with mostly, or all, chain rode. You'll be able to sleep better at night. I always get at least one size up from the anchor manufacturer's recommendation. The anchor manufacturer's recommendations are usually for normal weather anchoring (they sometimes describe the assumed weather conditions).

Last thing you want is wishing you had a bigger anchor while dragging during a storm at night.

Life is short. Plan for the worst and hope for the best.

That is what I go by...

I am getting a new boat built and I specified the anchor brand and size. The factory argued that the anchor I wanted was too big, but that's the anchor I am getting. I will be the one anchoring and I will be responsible for it.

[ranger58sb]

Originally Posted by billknny

The suggestion that you should size your ground tackle based on if you could lift it by hand... Really???

Every electric windlass that should be considered for a cruising boat should have SOME way of operating manually. Maybe not something you need often, but it should work. Even lacking that, your boat has winches. A rolling hitch and a couple lengths of line and you can pull anything up. Limiting the size of your anchor by such a criteria is just goofy.

Yep, been there, done that.

Our windlass does indeed have a way to lift our anchor "manually" -- except it doesn't work all that great. The final lift in that situation is really "manually". (And we don't have other winches, not having all of those sailboat things. )

Given that windlasses can be repaired or replaced... maybe that manual lift only has to happen once before the fix happens... and maybe lifting 75- or 100-lbs (or whatever) once can be acceptable...

But if you can't lift it, you may just have an issue that shopping could have addressed. My suggestion wasn't to go "light" -- just manually liftable. That could be 200-lbs for OP, for all I know...

-Chris

[bgallinger]

Originally Posted by chowdan

Hey all,

I am in need of all new rode, chain, anchor, and unfortunately windlass.

That being said, I am trying to scope out what would be best for my boat. My boat is weighing in at roughly 16t according to documentation and the scales when I launched her.

I am thinking I should get the Rocna 73lb anchor as based on their chart the 55lb would be the correct size so going one size up for being able to handle any storms the PNW or anywhere we go will make us feel a bit more comfortable.

Is this anchor size over kill? Would I be wise just to go with the 55lb and spend the extra $300 on going with all chain? It wouldn't adjust the cost of the windlass all that much as I will need to find one that will still support a 3/8" chain.

Any advice or recommendations welcome. Trying to align all the eggs before pulling the trigger on a windlass :\

Your choice of moving up one size anchor is wise. My personal preference is the Mantus (45 lb.) anchor with all chain (5/16"). I have a manual windlass and would LOVE to have an electric powered one. That combination of chain and anchor has given me years of restful sleep in all weather conditions. I would say anything heavier would be really tiresome to get it up and in the chain locker!

[eyschulman]

The multiple anchor tests over the last decade have all made it clear anchor weight and size are not the critical factor in holding setting and resetting performance. The heavy oversized anchor crowd ignores science and is very old school. You want anchor security(never 100%) use a good all around deep digging anchor sized as manufacturer recommends pick a good spot to set it and set it well with a adequate scope. Chain will help particularly with abrasion resistance and better catenary angle. If you like to hobby horse use a heavy monster anchor and lots of chain. For those who think there is no retrieval issues with extra heavy gear maybe they have not been doing this long enough. Have you ever had a windless fail? Yes I have. Where I have boated in PNW-East Coast and VI there are lots of well protected anchorages and its the skippers job to pick one right for the conditions. There is little need to get beat up unless we are talking extreme weather which for most is rare and even there multiple lighter deep digging gear still has more holding power and the weak point is at the boat chafe and weak fittings. If you still need more security get an oversized aluminum spade or fortress and stow it below, they come apart..

[noelex 77]

Originally Posted by eyschulman

The multiple anchor tests over the last decade have all made it clear anchor weight and size are not the critical factor in holding setting and resetting performance. The heavy oversized anchor crowd ignores science and is very old school.

The relationship between anchor size and holding power is well established. If other parameters are unchanged, the holding power rises roughly linearly with weight. I am surprised anyone would suggest otherwise.

If you are referring to better anchor designs, sure, a great, small anchor can beat a poor, big anchor, but a great, big anchor is better again

The only variable the OP is considering is anchor size. The science is quite clear.

I would recommend, for a cruising boat, the simple formula of fitting the largest anchor that can be comfortably managed.

[Mike OReilly]

Originally Posted by noelex 77

The relationship between anchor size and holding power is well established. If other parameters are unchanged, the holding power rises roughly linearly with weight. I am surprised anyone would suggest otherwise.

If you are referring to better anchor designs, sure, a great, small anchor can beat a poor, big anchor, but a great, big anchor is better again

The only variable the OP is considering is anchor size. The science is quite clear.

I would recommend, for a cruising boat, the simple formula of fitting the largest anchor that can be comfortably managed.

Completely agree, on both counts.

I’m not sure which "multiple anchor tests” eyschulman is referring to. All the ones I’ve seen are as you’ve described noelex.

Size definitely matters with regard to anchor. But design, proper rode, and most importantly anchor technique, are the MOST important factors. Good technique can compensate for an undersized, or poorly designed anchor. And conversely, poor technique can make the biggest and best anchor useless.

[evm1024]

Hansom looking boat. Do you hail from Everett?

I'm down here in the PDX area and use an 85# Mantus on my 50', 16 t boat. Also, I use 5/16" G70 chain which fits the same wildcat as 3/8" BBB.

From the Mantus tables your 41', 16 t boat would use a 65# Mantus for a "normal" anchor and up size 1 size to an 85# for a "storm" anchor.

For myself I've had great success with the 85# we carry but plan on going up to a 105# when we head out for an extended cruise in a year or 2.

I sell Mantus when not doing my day job and when making size recommendations I place a priority on displacement over length for boats that have "normal" or less than normal windage. The thinking is that the greatest loads on your anchor will come from shock loads when the boat is yanked around by the waves. In your case both the length and displacement align with the 65# and 85# as recommended above.

[eyschulman]

Originally Posted by noelex 77

The relationship between anchor size and holding power is well established. If other parameters are unchanged, the holding power rises roughly linearly with weight. I am surprised anyone would suggest otherwise.

If you are referring to better anchor designs, sure, a great, small anchor can beat a poor, big anchor, but a great, big anchor is better again

The only variable the OP is considering is anchor size. The science is quite clear.

I would recommend, for a cruising boat, the simple formula of fitting the largest anchor that can be comfortably managed.

I disagree the other variables are an issue why go bigger and heavier when smaller lighter and better design will work fine. The Op has picked a good anchor and the manufacturer suggestion for size is adequate for use other than open anchorage and storm use. If we follow the logic above (the biggest anchor you can put on the boat) that would be major overkill. Is that a little like avoiding injury from a car accident, drive a garbage truck? No lighter cars with safety improvements are the more practical answer. With some modification I probably can put 120-200lb anchor on my bow but why, in 60 years of boating on both coast never really needed that, did use two anchors several times. My major point is with a good reasonable sized anchor one should concentrate on the more important points of anchoring like picking a good place and bottom, setting well(with careful observation of set and position) and proper scope chafe gear and solid fixation point with good often inspected fittings. This difference of opinion reminds me of the battle cruising sailors had many years ago over the need for heavy weight, deep hulled boats to cross oceans. I know I will not change the minds of the heavy school but for those with open minds look around see what others are using and find out how often experienced cruisers are dragging with modern anchors of recommended size. We cruise and anchor out every summer and since I started using Spade, Ultra and Ronka type anchors can not remember dragging in over 20 years and none of my primary anchors were or are oversized. The storm anchor lives in the bilge where it belongs 99.5% of the time.

[Jim Cate]

It is all very well to pontificate upon the adequacy of smaller anchors, predicated on protected anchorages, good technique, etc. Yes, with those provisos all will be well.

But in the real world of extended cruising, sometimes even skilled and experienced skippers can't meet those standards, and it is in those situations that an anchor larger than the recommended size will be of help.

I know that I have had to anchor in places with poor protection or bad holding or insufficient room for good scope, and unforecast wx events have surprised me. Carrying an extra 20 lbs of anchor around routinely is a small price to pay for security in such circumstances. And having to retrieve and fit a stored storm anchor isn't a viable solution to the problem. IMO (and with considerable experiience to back it up) the "storm"anchor should be your primary anchor, in use at all times.

Jim

[kmacdonald]

I downsized a solar panel and anchor. Use the smallest you are comfortable with. My 10 lb fortress holds my 16000 lb boat just fine. I sleep just fine also.

[Smokeys Kitchen]

Here's what we have used the past 2 years on our trip up to Alaska and back.

25kg Vulcan (Rocna w/o the hoop)
210 ft 5/16 HT chain spliced with 120 ft 11/16 8 plait
Muir 1200 Atlantic windlass

Boat is a 40' Pacific Seacraft - ~ 29,000 lbs at current haulout

We dragged twice in the last 2 years because of complacent anchor setting on my part.
The windlass is original equipment and broke a part on the way up last year. We had prompt, excellent service from the distributor in Vancouver who got the necessary parts to a float plane to send them up to us. I'd go with another Muir if I had to get a new one.