too big an anchor?

[Hippocampus]

pSN get your point and it’s valid but most folks only take out the Danforth/Fortress for mud. It’s holding power in gravel, weed , grass , dead coral bits sucks. Exactly for the reason you mention. It’s a bear to get a set with those bottoms.
Anchoring is a coastal concern. Totally agree at this point having a next gen as your primary is the way to go. Don’t care what the tests show beyond what it might mean in day to day use. Only care what the holding power is when I drop the anchor where I am. Far as I know an anchor that doesn’t set has no holding power so think a danforth style makes little sense as a day to day for most people. Only exception is in the dinghy where it lies flat and doesn’t take up useful room.

 

[guy with a boat]

I too often see comments about how bigger is always better for an anchor, and how you should always oversized beyond recommendations for your boat.

It is worth keeping in mind that there should be some balance in the ground tackle system overall. Obviously you don’t want to exceed your windlass weight capacity, but the chain (or combo rode) and anchor should be somewhat balanced. There is some point at which the forces on the ground tackle can cause it to fail. You are far better off having that failure mode be your anchor dragging, than having your chain part. You can reset an anchor but that’s hard to do if you are drifting away in a storm with only half your chain still attached.

If your answer is that the chain cannot possibly break even in extreme conditions with a huge anchor, then you are running chain sized well beyond what is typical for a given boat size. And let’s be clear that I’m not talking about moderately upsized anchors being an issue, I’m specifically talking about greatly oversized anchors that seem to be frequently recommended by keyboard experts.

 

[DDW]

Getting back to anchors most all anchor tests tell you how much holding power each anchor has at long scope. That’s it. And few boaters anchor at long scope as in over 6-1. And more importantly most seldom if ever anchor at long scope. But there’s lots of crowded anchorages and deep anchorages and small anchorages. All needing a short scope. But even more important that short scope is setting ability. Perhaps the most important element of anchor performance is setting ability.

Are you not familiar with Panope's anchor tests? All of them tested on short and shorter scope, including setting and resetting ability.

 

[Nomad Willy]

freshalaska wrote;
“Also I always back down on the anchor jumping up the rpm’s 200 at a time till I get to 2600. And numerous times the anchor will drag if less than a 5 to 1 scope. Often the anchor will hold to 2200 rpm but not 2600 with much less than 5 to 1.”

The Rocna is a good anchor for extremes .... but not for short scope. A Manson Supreme would do considerably better backing down hard on short scopes. But not so well at other things like mud chocking.

Sounds like you are conducting an anchor test when anchoring. What size engine and prop?

 

[Nomad Willy]

DDW,
Oh yes very familiar w Steve’s tests.
But Steve tested in one spot. A uniform soft bottom very close to Port Townsend Wa.

I don’t think he tested it but a great anchor for that anchorage would probably be a Super Max. Think fluke area. Anchors like a Northill w a very small fluke will perform flawlessly in quite moderate conditions but don’t pull very hard on the rode.

 

[freshalaska]

Nomad Willy I take anchoring very seriously. You know how hard it can sometimes blow is SE.
my engine is a high rpm Yanmar 62 hp. Prop is a set pitch 19 inch diameter three blade and not sure the pitch but not sharp or not too flat. Transmission is around 3 to 1 but I’m not sure on that. At 2600 rpm the chain gets pretty tight but not bar tight. If figure if she holds at 2600 I’m not going drag if things start blow up. Maybe over kill but if you anchor enough times especially Alaska sooner or later you get caught with your pants down.
On another boat we survived without dragging in two typhoons in the Philippines but had long scope and many anchors out and the waves, fetch was not much. Winds I don’t think where much over 75-80 knots. But when the wind increased things started to go air borne and other boats started dragging.

 

[Nomad Willy]

Hippocampus wrote;
“To further expand. Been taught a “proper” boat should have multiple anchors and rodes. Past teaching about storm anchors is probably antiquated as next gens are such a step up that your daily will serve.”

To an extreme. That’s old school and 99% of the boaters here don’t do old school. They expect to buy one anchor to do everything ... no redundancy needed .. thank you.

And that mindset works well until it dosn’t. And anchors have advanced to the point that many can go forth w one bower.
But if you “went forth w one anchor, and it was a Navy anchor it would still fly ... to a point.
But not here. A second rode is not really uncommon even here but it’s usually stuffed way down in the bilge. There are exceptions but those boats are big and the money for a ready to use 2nd ground tackle system is found on bushes. And for the really big boats ... on trees.

But the notion of one thing doing everything is not new .. not at all. For 50 years and probably more there has been a relentless effort to build a flying car. Guys go to too many movies I think.

 

[Nomad Willy]

freashalaska wrote;
“Nomad Willy I take anchoring very seriously. You know how hard it can sometimes blow is SE.
my engine is a high rpm Yanmar 62 hp. Prop is a set pitch 19 inch diameter three blade and not sure the pitch but not sharp or not too flat. Transmission is around 3 to 1 but I’m not sure on that. At 2600 rpm the chain gets pretty tight but not bar tight. If figure if she holds at 2600 I’m not going drag if things start blow up. Maybe over kill but if you anchor enough times especially Alaska sooner or later you get caught with your pants down.”

I suspected that and thank you very much for the clarification. That’s perfect for you w your boat. When in SE I always backed down but my power is only 37hp and a 2.57-1 ratio w an 18” prop. But I usually back down to about 1400rpm. And to be clear one is testing the seafloor backing down fairly hard as we do but in Florida on a sand bottom that may fall flat .. so to speak.

 

[Hippocampus]

Yup makes me crazy. Don’t care where you are there’s pop up t storms, squalls and other hyper local stuff that may make you drag. Now see boats with just one roller and no way to handle both chain and line. That stainless steel bit of boat candy is beautiful but under sized for anything but a lunch hook. Although we’ve been there first have often moved when we see what goes on around us. Several times doing that has saved us from a bump. Now take pictures of the boats around us just to save hassle when an insurance claim might come up. OP is to be congratulated as he’s thinking about safe anchoring. Good on him.

 

[rslifkin]

Yup makes me crazy. Don’t care where you are there’s pop up t storms, squalls and other hyper local stuff that may make you drag. Now see boats with just one roller and no way to handle both chain and line. That stainless steel bit of boat candy is beautiful but under sized for anything but a lunch hook. Although we’ve been there first have often moved when we see what goes on around us. Several times doing that has saved us from a bump. Now take pictures of the boats around us just to save hassle when an insurance claim might come up. OP is to be congratulated as he’s thinking about safe anchoring. Good on him.

The key in there about only 1 roller is why I went for keeping the big guns on the bow and have a Fortress (and should add a second bigger one) as a secondary. A second anchor on my boat has to be hand launched, which isn't a big deal with something like a Fortress. But I have no desire to manhandle the 73lb Vulcan, so that one lives on the roller and gets to be the primary, even if it's a bit overkill for this boat 99% of the time.

 

[rsn48]

40 ft, 28000 lbs, dispacement hull.

Just for academic purposes I have used the Rocna chart to see what I would purchase for that boat. First if 28,000 lbs is the dry weight, I'd assume the boat is really roughly around 33,000 pounds. So using the chart, the Rocna 33 would work, but like many I then would go one up to the next sized anchor which is the Rocna 40 (an 88 pound anchor).

 

[Nomad Willy]

I don’t know what a Mariner 28 is but I have a 30’ boat at 17000lbs so a 2-1 scale may apply. Like my present anchors are a bit over 20lbs and that should equate to a 33,000lb boat would nicely go forth w an 80lb anchor.

A great deal of experience w the boat an many anchors indicate the 80lb choice should be a good one.

 

[rsn48]

I don’t know what a Mariner 28 is

Nobody does....lol. Mariners were apparently built in Vancouver. I have seen about 8 for sale in the back of older Pacific Yachting mags, but I think the last one I've seen was in a 1995 issue.

If you are a bit of a "woodie" fan, you might be familiar with the name "Grenfell," a local Vancouver chap who put out quite a number of wooden boats over the years, but also sold designs he never built. There is speculation my boat is a Grenfell design though I am beginning to doubt this claim. If you have attended the wooden boat show in Port Townsend, you would have seen some Grenfells. They are noted for their lapstrake hull designs.

I suspect my boat is one of the remaining Mariners still cruising BC waters.

What I would like to see is a discussion of heavy anchors combined with long all chain rodes and how that affects bow performance of smaller boats, lets say under 35 feet.

 

[Nomad Willy]

rsn48,
Very interesting about the Grenfells. Picture?

I was deprived of the privilege of driving by your house as we usually do a car run up the east side of the big island. Of course we’re up on the highway. Missed it this year for the obvious reason.

Re heavy ground tackle I have no experience as I strive to keep the bow weight low. My current rode chain is 4’ of 3/8”ths chain. My theory is that the advantage of chain is in the weight/downforce on the anchor shank during the setting of the anchor. It gives it negative angle of attack that brings about “setting”. For anchors that set laying on their side (as many now do) the chain holds the end of the shank down. With the shank sticking up like typically in a store the shank is high up and the fluke is flat on the seafloor ... 0 angle of attack.
And when this happened in Steve G’s Anchor Setting Vids the anchor just skidded along the seafloor. No set and no hold.
So my rig requires 5-1 scope (or so) to get the shank down on the seafloor. Then the anchor sets if one does not pull the shank up too soon. Some anchors like the Danforth and the SUPER SARCA set readily w the shank up and the fluke flat on the seafloor. One of the reasons I’m drawn to the SS.

Most here know well of my distain for all chain anchor rodes. My feeling is that most of the chain being all one size is a waste of applied weight. Once the anchor gets set the treasured low catenary is mostly not of value. So as you might guess I’m a big fan of a mixed rode. Ideally it would employ 2-3 different sizes of chain. The fishermen in SE Alaska do this often. That is about 20% of them do. Heaviest nearest the anchor (some even employ studded chain) to medium sized chain and then to the lightest chain for the boat/anchor size. And then, finally to an appropriately sized nylon line.

Not being a extra heavy and all one size of chain fan so that’s about all I can contribute. Oh and to my knowledge I have never dragged .. or can’t recall it.

Oh I can say that 1/4” chain seems the only choice chain size re your stated requirements ... that I know of. Is there 5/16” chain for boats? Unless it was sone unusually high allow strong stuff it would seem to be too weak for the application.

Also re my 4’ of chain ... that’s just recently. Prior to that I used 8 and 15’ of chain.

 

[rsn48]

I think I have told you this before, but I've actually been in bustling downtown Concrete.

Here is a link to Nauticapedia informally run by the Maritime Museum in Victoria. The folks at Nauticapedia have compiled a list of all boats and manufacturers they can find of boats built in British Columbia. If you go into the tab that says something like Vessel Search or whatever and input Capricorn (my boat) you will see a picture of it before I undertook a massive refit, but it still pretty much looks the same.

Anyway this link takes you to Grenfell manufacture in the listing of manufactures and boats, you will see it goes on for two pages and a bit:

Vessels Built by Grenfell Yachts Ltd.

Here is a link to a number of Grenfell images, one of those boats is in my marina not to far from my boat. When I was bringing back my boat after refit, the owner of the Grenfell was by his boat working on chores, when he spotted me, he gave a big grin and a wave.

grenfell boat images - Google Search

Here's a 55 footer:

Here is a 36 Grenfell:

 

[Hippocampus]

Willy depends where you are. In Caribbean, Maine and many other places with coral heads, protruding rock or other strongly abrasive features rope doesn’t cut it as it just gets cut every time the wind dies and then picks up or there’s a wind shift. Also kellets are a PIA and the catenary effect is quite meaningful you get from chain. Finally you look at chain and usually know if it’s time to change it. Salt crystals, sand and dirt slowly cuts the fibers in rope. You may have no idea what’s the health of the rope just looking for signs of outside chafing. Nylon is the worse for that beyond UV damage repeated stretching kills it but most synthetic ropes get creep so have a service life even when they look good.
Know sometimes due to weight or storage issues you are forced to use rope. If I was anchoring in more than 100’ seems quite reasonable as it’s very unlikely it would ever rest on the bottom and chain weight would be excessive. But unless you’re someplace where there’s no chance of abrasion and weight’s a concern will agree to disagree.

 

[Peter B]

40 ft, 28000 lbs, dispacement hull. Boat came with 2 cqr's on the front (45 and 35) but an 88# Rocna which I picked up for a very fair price is what I'm considering. A 55 Rocna was my original plan. Boat is very unfussy about trim especially with lighter fuel loads (aft tanks, 400 gal).
My gut tells me to rig it...

MikeyG, you've received a lot of somewhat conflicting advice. The simple fact is, you already have this somewhat over-sized (for your boat) anchor, which I assume weighs 88lbs, as there is no number 88 Rocna.

The 55lb one would have sufficed quite well for a boat your size and weight, but as you have this thing, and it is just two sizes up from recommended by Rocna, I don't think it anything other than a no-brainer to rig it up, and just see how it all goes.

If over time, it becomes apparent the winch is straining at depth, or the weight is causing some trim issues, then you can always trade it in on a 55. You have the thing, so it's not an issue of "which do I buy?"

Frankly, I think it will do fine, and I wouldn't even waste time backing up to set it, unless there's no current or wind, other than a bit of a check back-down before heading to the bunk, if there is any doubt, and a blow might be coming.

 

[Nomad Willy]

Hippo,
Unnecessary weight anywhere in the boat is bad. Unless it’s ballast.
But there are benefits to the weight of anchors and chain in the rode.
But the benefits come and go w the variables that also come and go.

If you attach a chain 20’ up in a tree and 60’ feet out from the trunk install a dead man or a set anchor. Then 10’ up from the anchor you attach a 10lb weight to a link in the chain. Measure the catenary angle. Remove the 10lb weight and attach the 10lb weight to a link in the chain 10’ down from where the chain is attached to the tree. Measure the catenary. It will be greater .. as in a wider angle.

W/O doing the drill I can tell you that the catenary will be better w the weight attached to the lower point. As in close to the ground and set anchor. And w the 10lb weight attached closer to the high point on the tree the catenary will be less than the free hanging chain.

So unless I mucked up and arranged my words wrong the catenary is better w the 10lb weight attached lower.
So from the example above wouldn’t it tell you that w a chain double the chain weight but half the length would by far be better attached to the anchor? And if you attached the half length chain to the tree the catenary would be worse for anchoring than w the original full length chain. Yes the cat angle would be less.

Actually it has been said (on TF) that the best place for weight on an anchor rode would be about 10-15’ up the chain from the anchor. Marin Faure had some physics man figure it out.

But for sure the best catenary dosn’t come from an all chain rode. What comes from an all chain rode is convenience. And an unnecessarily bow down boat. Assuming it was trimmed for n all chain rode.

So for best catenary about 20’ of chain is close to ideal .. for a typical larger trawler.

 

[MikeyG]

Yep, thinking bird in hand she's going on. Worst case I replace it with a 55 and hide it for a special occassion. Appreciate all the input!

 

[Hippocampus]

Eric have the utmost respect for your knowledge and experience but there’s a difference between theory and practice. Where you cruise what you say makes sense. No argument. Still abrasion and sudden failure is a concern for many cruisers. Over the last 35 years have knowledge of this occurrence on multiple occasions. In Newport harbor when entangled in junk. In Main of War Cay due to coral sand (just sand not even a head), in Southwest Harbor from rock. In Le Marin from being cut by a prop. The list goes on. I’ve yet to hear of a cut or abrasion failure due to chain except for gross negligence with old chain not being replaced. Same with swivels. Just another failure point. So you’re right and logically chain/rope should serve. But in the real world it presents another unnecessary risk for many. One of my biggest fears is taking the dinghy in for chores or sightseeing and returning to find no boat. So even with the downsides of chain ain’t changing.
BTW several new designs have moved to put the chain locker toward the middle of the boat. Look at Boreals as a nice example. Have seen this in a light ice certified motor one off as well. Have also seen wire rope but this also is abrasion resistant.
If the concern is weight get the Pb out. Change to Firefly or Li. Better performance and huge weight savings.

 

[psneeld]

Tiying anchor chail to a tree has no relavence to most if not all anchoring situations.


The tree is a fixed object, a boat is not.


As current or wind increases....the energy expended varies as the boat begins to and continues to move....the catenary is constantly changing and the more the chain straightens, the more effect weight has further up the chain.


While I haven't or even could do all the necessary math to explain it....I just know that MY common sense backyard mechanic, rule of thumb, etc...etc eyeballing experience pretty much disagrees with many of the theories of anchoring often proposed about catenary and chain.


If only that a boat at anchor does not act like a tree.... I am pretty certain of that.

 

[rslifkin]

For what it's worth, I've got a 73lb Vulcan on my 38 ft / 26k lb (loaded weight) boat. I've yet to feel it's too big. And every once in a while I've wondered if I should have gone for the 88lb (it would have fit, just barely), although the 73 has never been inadequate.

 

[Nomad Willy]

Big kahuna

Re big anchors this is the biggest I've seen on a trawler type boat.

This boat is a pleasure boat, fish boat and bus to and from town. Owner lives on a small island near Craig Ak about 50miles NW of Ketchikan. He "parks" this boat in front of his house.

So the anchor needs to hold in an 80mph wind.
The Navy anchor is 500lbs.
At the time I took the pic it was big enough.

 

[OldDan1943]

Re big anchors this is the biggest I've seen on a trawler type boat.

This boat is a pleasure boat, fish boat and bus to and from town. Owner lives on a small island near Craig Ak about 50miles NW of Ketchikan. He "parks" this boat in front of his house.

So the anchor needs to hold in an 80mph wind.
The Navy anchor is 500lbs.
At the time I took the pic it was big enough.

500 pounds? well, between the weight of the anchor and the amount if chain he must have, it will hold the bow down when heading into the wind.
Hmmmm, did he buy that anchor, steal it or salvage it from the deep?

 

[Nomad Willy]

Dan “Hmmmm, did he buy that anchor, steal it or salvage it from the deep?”

I have no bloddy idea Dan. And the 500lbs was dock talk from someone l knew.
But if you’re implying I associate w thief's .. no l don’t.
I posted this for your entertainment.

 

[OldDan1943]

Dan “Hmmmm, did he buy that anchor, steal it or salvage it from the deep?”

I have no bloddy idea Dan. And the 500lbs was dock talk from someone l knew.
But if you’re implying I associate w thief's .. no l don’t.
I posted this for your entertainment.

Nope, not me.

 

[Nomad Willy]

But Dan is your anchor now too small?

What we should do is have everybody submit their boat weight and anchor weight.

Run the numbers and establish an average anchor weight per boat weight. Like when I assembled a “lbs per hp” ratio for powering.
In the end you’d have a Xlbs per lb of boat average.

Should be something like 4 tons per 10lbs of anchor. Or 4-1, tons to lbs.
Would you do that Dan? You seem to have the time.

 

[rslifkin]

But Dan is your anchor now too small?

What we should do is have everybody submit their boat weight and anchor weight.

Run the numbers and establish an average anchor weight per boat weight. Like when I assembled a “lbs per hp” ratio for powering.
In the end you’d have a Xlbs per lb of boat average.

Should be something like 4 tons per 10lbs of anchor. Or 4-1, tons to lbs.
Would you do that Dan? You seem to have the time.

That works up to a point, but windage is a factor for how much anchor is needed, not just weight. And as boats get larger, anchor needs get proportionally smaller.

Boats gain weight faster than windage, meaning that larger boats are less affected by gusts and will produce less spikes in anchor loading with wind gusts. Heavier boats tend to also be deeper in the water, meaning they have less footprint vs weight, so they'll feel waves a bit less too, which also reduces the load spikes.

As an example, my 38 footer is about 26k lbs loaded. Something like Simi's 60+ footer may have twice the windage, but easily 4 times the weight.

FWIW, I've got 356 lbs of boat per pound of anchor, or 5.6 lbs of anchor per ton (2000 lbs) of boat.

 

[OldDan1943]

Eric,
44# plow, WWL 32ft 6", Net 12ton, 275ft 5/16 chain
2nd anchor, aluminum fluke type anchor #31 stamped on it (forgot the brand), 12ft of 5/16 chain and anchor rode as long as piece together 5/16" and 1/2" nylon line. These are my traveling lines.
Good enough to pass muster?

 

[Nomad Willy]

OD sure. Could you handle a Claw (did you call a Claw a plow?) one notch up ... what would that be (56#)? And if it was a Bruce ... smile.
What’s an aluminum fluke anchor .. a Spade?

Just what anchors DO you have Dan?