Anchor Size: Multihull v. Monohull

[Gone2long]

I have a 40' trimaran, which draws only 3 feet for the main hull and about a foot for the outer hulls. The boat weighs only 4 tons.

Lewmar says that their Delta 35lb anchor is appropriate for a sailboat between 40 and 50 feet, while their CQR is good for a boat measuring 35-50 feet.

I am wondering if these stats are accurate for a multihull. For instance, I have a light boat with negligible displacement; but, on the other hand, the boat is wide, creating a lot of windage on three different hulls.

All input greatly appreciated.

G2l

[boatman61]

I would totally ignore how long the boat is.. irrelevant.. work on how Heavy your boat is instead.
But that's me.. others probably (usually) know better..

[UNCIVILIZED]

The figures which Lewmar gives for sizing their anchors, is rather undersized, for most any type of boat (multi or mono). Especially in a cruising context.

So if you plan on going with one of those anchors, as opposed to a new generation type, you'd do well to go a size+ larger than spec'd in their catalog.
As more or less, a multi's windage cancels out her light weight. So going with an anchor for an equivalent length monohull is likely the way to go.

For instance, on my 31' Searunner (3 tons +/-), I had a 35lb CQR as the primary, & a Danforth sized for a 35'-40' mono (I don't recall the size/weight) as the 2ndary. And kept 1 or 2 spare anchors, stored in the bilges, in case I needed a 3rd hook, for whatever reason.

[Gone2long]

Originally Posted by UNCIVILIZED

The figures which Lewmar gives for sizing their anchors, is rather undersized, for most any type of boat (multi or mono). Especially in a cruising context.

So if you plan on going with one of those anchors, as opposed to a new generation type, you'd do well to go a size+ larger than spec'd in their catalog.
As more or less, a multi's windage cancels out her light weight. So going with an anchor for an equivalent length monohull is likely the way to go.

For instance, on my 31' Searunner (3 tons +/-), I had a 35lb CQR as the primary, & a Danforth sized for a 35'-40' mono (I don't recall the size/weight) as the 2ndary. And kept 1 or 2 spare anchors, stored in the bilges, in case I needed a 3rd hook, for whatever reason.

Thanks for the insights. I have two Danforths, both smaller; but my 35 pounder has served me well so far in 20 knot winds, 2 foot seas, with 50 foot of chain out in 13 foot of water. We swung 360 at one point, and the chain made a lot of racket, but all held pretty well.

Any other related insights would be appreciated.

G2L

[boatman61]

Originally Posted by Gone2long

Thanks for the insights. I have two Danforths, both smaller; but my 35 pounder has served me well so far in 20 knot winds, 2 foot seas, with 50 foot of chain out in 13 foot of water. We swung 360 at one point, and the chain made a lot of racket, but all held pretty well.

Any other related insights would be appreciated.

G2L

Get a decent anchor.. else one day you may well be viewing a beached boat.. save your Danforths for Kedging..

[Gone2long]

Originally Posted by boatman61

Get a decent anchor.. else one day you may well be viewing a beached boat.. save your Danforths for Kedging..

Thanks for your note, but I am wondering if you did not pick up on my earlier post, which notes that the 35 pounder is a Delta.

In any case, always good to hear from you salty dogs. : )

Regards,

G2L

[boatman61]

Originally Posted by Gone2long

Thanks for your note, but I am wondering if you did not pick up on my earlier post, which notes that the 35 pounder is a Delta.

In any case, always good to hear from you salty dogs. : )

Regards,

G2L

Apologies.. missed that..
my mind was elsewhere.. GW and Islamic terror in Europe.. hundreds of years ago..
Thought you were asking about buying one..

[AD28]

I have a 40' 16.5K lb cat.

She lays to chain with a 45 lb Manson Supreme, and has done so through a 180 degree shift with a 50kt blow accompanying it; a 60kt blow emergency set; a 50kt squall; and a 30kt t-storm with fetch. (those are my worst so far that I recall)

I do not skimp on scope. To me, short scope is 5:1, and I'm normally setting on more (except that emergency set)

35lb is the low end but you're probably ok. Scope can make up for many of an anchor's flaws.

That said, don't touch a Bruce/claw with a 20' pole. In the 'emergency set' situation a boat which was (not) laying to a Bruce drifted down on me, the only one in the anchorage who came off his hook. Bruce. Not even once.

btw this is a very interesting series of videos of anchor setting that a talented amateur has produced. Read that to mean, 'not done by an interested party.'
https://www.youtube.com/user/flygoodwin

[boatman61]

Damn.. and there's me been using a Bruce successfully for 35yrs... but I guess 'Idiot Proof' anchors have their use's.
Just wish more Charter boats had them.. idiot proof anchors I mean

[Training Wheels]

I use a Spade A100; I'm 44' and 10,000#. It's held in 50-60 knot gusts. Also use Fortress FX-23, also a great anchor. I am the anchor windlass, so weight is doubly important to me.

The Spade fits much better in my anchor roller, but it is $$$$$.


Sent from my iPad using Cruisers Sailing Forum

[Gone2long]

Originally Posted by boatman61

Apologies.. missed that..
my mind was elsewhere.. GW and Islamic terror in Europe.. hundreds of years ago..
Thought you were asking about buying one..

My mistake, not yours. After reading my original post, I must apologize for not making clear the anchor(s) I actually own.

By the way, terror in Europe definitely seems a worthwhile distraction : )

Best regards,

G2L


Famous quote: "You musta been readin' my mail' - Kris Kristofferson - "To Beat the Devil"

[TrentePieds]

"btw this is a very interesting series of videos of anchor setting that a talented amateur has produced. Read that to mean, 'not done by an interested party.'
https://www.youtube.com/user/flygoodwin"

Lovely videos. But it strikes me that if I were a Bruce afficionado, as some of you know I am, I could, if I wanted, using a Bruce, produce a perfect plagiary of these videos, showing that the Bruce is the way to go.

Major deficiency in the argument made by AD28 regarding the dragging Bruce is that he sez nothing about the holding ground, and he sez nothing to indicate that the Bruce was set by a competent seaman. We all know that the Bruce concept was developed specifically for clean sand bottoms, and that a Bruce (and all others) won't bury on bare rock.

Implicitly AD28 makes the point that weight and scope saves the day - or night :-)

TrentePieds

[LeeV]

We have several anchors for our 36' which is somewhere between 8k and 11k depending on what we decide to leave aboard. :-)

I'm going to use the A100 (which Spade just replaced for free - great customer Svc) as our main on about 15' chain and 250' rode. We'll probably use a smaller Danforth as a lunch hook.

I was going to remove the windlass installed by the p.o., but suffered a heart attack 10 days ago and may just leave it for the convenience!

[UNCIVILIZED]

Originally Posted by Gone2long

Thanks for the insights. I have two Danforths, both smaller; but my 35 pounder has served me well so far in 20 knot winds, 2 foot seas, with 50 foot of chain out in 13 foot of water. We swung 360 at one point, and the chain made a lot of racket, but all held pretty well.

Any other related insights would be appreciated.

G2L

Yes, your initial post was penned in such a way so that you made it sound as if you were shopping for anchors. And that your primary candidates were 35lb Lewmar; Delta's, & CQR's. Or so I believed after reading it.

As to insights, I've a few:
- 35lb (or a bit more) is perhaps big enough for a Danforth for a boat that size. Your primary hook should be a good bit bigger.

- Scope: You need to use more of it. A LOT more. Because... If you're in 13' of water, & your bow's 5' high, plus, most places, there's a minimum of a 5' range of tide. Then your ground tackle is operating with 23' of "depth" to deal with. So that if you have 50' of rode out, you're on 2:1 scope.
Which is where Tarzan would say: "That's Bad Juju Bwana". Especially if/when, on top of that; the breeze goes up, the boat swings (due to wind or current/tide), or, some seas build... which leads to the next item.

- 20kts ain't much more wind than comes out of someone's backside, after eating a bowl of chili.
As a realistic minimum, you're ground tackle should be up for twice that (which means 4x more load, from wind only). Or better yet, 3x that, aka 9x load. If you're wanting ground tackle for a serious cruising context, that is.

Plus, when it's blowing like that, most any boat's going to be yawing, & or, sailing back & forth a fair bit (some even maniacally). Thus increasing it's windage (& subsequent ground tackle/anchor loading) by that much more.

- And then, there's the "serious bits". Waves & fetch. As the shockloads from them can be pretty unfriendly on your entire ground tackle system. Especially with regards to your anchor's staying in the same zipcode.
Particularly when the weather comes in from an unexpected direction, & you're now on the wrong end of a mile or more of open water, over which the waves can build.
Ever seen guys surfing in 5'er's with a 12 second period? I'm just sayin'...

Sorry if the above's a little harsh. But I ain't sure how to lay the reaility of it out any other way. And as a famous sailor once said: "The sea has little mercy. The rocks, none at all".

[donradcliffe]

I'd ditch the delta(Drags ELegantly Through the Anchorage) and the cqr (Can't Quite Reset), and go with a modern anchor in the 45-50 lb range, like a Manson supreme or rocna 20kg, or super sarca 22kg--they all look and perform the same. The spade is good, but more expensive. Forget the Bruce 20kg.