Best hull design for comfort at anchor?

[JPA Cate]

Jim made one that was hinged, but folded flat, heavy enough to sink on its own. It folded as it went down, then opened up to resist the up-roll. Like Don's, it deployed off a snatch block on the end of our spinnaker pole. As I said, it worked okay, but we got more used to the motion and it fell into dis-use, though it helped in the long run.

A.

[massnspace]

Originally Posted by Don C L

I've used those Davis Rocker Stoppers, and they work fine, but they do require the weight and they don't stow easily in my small boat. So I switched over metal frame designs similar to the attached article with spinakker poles as outriggers. The metal ones are easier to stow and don't require a weight.

https://www.cruisingworld.com/how/re...oppers/#page-4

The last time I checked, the metal frame type cost about $1000 each. If the objective is the also stop fore and aft rocking, you will need a minimum of 4. $4000, or $300-$400 for all the Davis….and, on a boat that displaces 24,000 lbs, a few extra pounds of weight carried in deck buckets is of no real concern…just throw them in to deploy, you don’t have to carry the weight around anywhere.

Also. I owned two of the metal types before. They came on a 39’ sailboat I bought, found them in the lazarette. I found them noisy (you could hear them opening and closing all night, as water transmits sound well), and they fell apart after not so many uses (rusted and failed where the metal swivel pins were welded to the vanes). I don’t know what “brand” they were, they were unmarked. Maybe the newer designs are better?

Forespar used to make a metal one. I think about $300…it kind of folded in half like a bird flapping wings. Never used it, but now it’s too late to try as they are no longer made (which leads me to believe they did not work well)…

Anyway, nothing really to break on the Davis type…no moving parts….just throw them in….and we use 4 of them on a 23’ sailboat….easy to store. I have them all pre-rigged on line, and I have a caribeener type clip on the weight, so I can just clip it onto the last stopper and throw the whole shebang in….

[Don C L]

I found both of my metal frame flopper stoppers in a local consignment shop. I think they were $100 each. Quite a score by my calculation. One has metal leaves and the other plastic. Haven't heard any noise yet. But the plastic ones are fine too. I've heard of people using them for pitching off the bow and stern but I have never even considered it. Even the old CCA designs aren't that bad, are they? (By the way, could be wrong but I always thought hobby horsing just referred to the pitching motion when sailing upwind in a CCA design; the kind that slows you down.) Pitching doesn't bother me, it's the rolling that'll get ya. If it is pitching that bad there must be big swells in the anchorage and I'll probably be up most of the night anyway keeping an eye on things... like did the pitching just yank my anchor out?

[Don C L]

Originally Posted by JPA Cate

Jim made one that was hinged, but folded flat, heavy enough to sink on its own. It folded as it went down, then opened up to resist the up-roll. Like Don's, it deployed off a snatch block on the end of our spinnaker pole. As I said, it worked okay, but we got more used to the motion and it fell into dis-use, though it helped in the long run.

A.

I think mine saved my marriage.
Or at least they saved me from having to argue why I should keep the boat.

[Wandering1]

Originally Posted by Chotu

there is no replacement for displacement. Or is there???

I have been living at anchor most of my adult life. I have slept more nights at anchor than I have on land in my entire life. Starting with that little bit of résumé

over the years I have learned what makes a boat feel comfortable or not.

The first technique is a monohull technique. You need a long waterline, a lot of beam and lot of displacement. Just big and heavy. Big enough, heavy enough, you won’t feel the chop in the Anchorage. As long as you stay facing into the waves.

The second technique is a catamaran and modern mono hull technique. It’s the one I prefer obviously. Form stability. If you have something that has a rounded shape to it, it’s going to rock in the direction of that rounded shape. Just like the bottom of a rocking chair basically. They do call it rocker after all Boat design. it does just what it’s called. The smaller, the length and the deeper the rocker, the more it’s going to rock like a rocking chair. That’s why when a monohull goes sideways and the waves come from the beam, it rocks like crazy. It only rocks some when they come forward.

now, The modern, extremely lightweight boat has a different design. There is very little rocker. There is very little boat below the water at all. It’s fairly flat. More like a regular chair with the four legs. Or like sitting on a milk crate. These things don’t rock. they are flat on the bottom comparatively. and if you stick a couple of these flat sections next to each other, as in a lightweight Catamaran, you are going to be rock solid in that Anchorage. My boat doesn’t move at all. Nothing moves it. Even at sea it only goes up and down. Like an elevator. It doesn’t rock. It doesn’t rock forward, it doesn’t rock side to side. It just goes up and down.

this is because it’s 25 feet wide and has very little rocker to it. sits like a milk crate on top of the water. Or more accurately, like a block of Styrofoam.

so you are way off about the Catamaran. That’s the main point I want to make. A heavy Catamaran has a lot of rocker and a ton of hull below the water. it’s exactly what you don’t want. It will behave like like a monohull and it will rock fore and aft at least. when choosing Catamaran, you want something that has very little bottom paint. The less bottom paint, the better the boat. also, the better the boat will behave at anchor

I drew the roughest quick sketch for this post. On the top, you can see the forms stability. On the bottom, you can see a standard small monohull. waves come from the left side of the page. In your imagination, you can picture how those two different shapes are going to react.

I have a different take on this. You don't move much because your boat is big. By comparison, I have been in a Lagoon 380 in a choppy anchorage in the Caribbean and the motion is far from comfortable. We sail a 44ft monohull ketch. 41,000lb displacement, 7'2" draft. Tall rig. We don't rock at anchor when modern monohulls of the same length are rolling to a side swell. Our hull is round bilge not flat. We have 13000lbs of ballast low down in the deep keel. We pitch as we are relatively short waterline but pitching is hardly noticeable compared to rolling. There are some anchorages we use that can be untenable when a swell creeps in. We are normally the last to leave as we don't get impacted the same as other monohulls and catamarans of the same length

[CaptainRivet]

Originally Posted by Jim Cate

A riding sail set on the backstay will settle most boats that tend to sail around at anchor. Reducing windage forward also helps.

Jim

Well I had even better a 2nd mizzen riding sail on the 2nd track on my old longkeeler ketch , that nearly all the time went up on anchor.
But my 40ft catamaran now is much much comfortable at anchor and it's a lighter one but not so much windage as the Lagoon condo.
Lagoons wide hulls, beam and simply weight are even more comfortable at anchor as both also dampens movement, the bigger rocker makes it stronger. So the shorter Laggon yes they get quite rocky but from 45ft on not much anymore as the longer waterlength just counterblance that. And well above 50ft cat really moves up and down like a lift. Yes they have more windage but really you don't feel much when they swoy from side to side, a longer bridle helps here too.
But a mono will never be as comfortable as a cat because even with riding sail still heels from side to side especially when wind and swell comes from a different angle.

[noelex 77]

If you are prone to seasickness, at anchor, cats are usually better than monohulls. The roll is reduced, although the pitch changes are more severe.

If you have concerns, it is better to try both. The quicker period of catamarans sometimes upsets stomachs more than the slower roll of monohulls, but overall, catamarans are better in this regard if this is an important consideration.

[Wandering1]

Originally Posted by noelex 77

If you are prone to seasickness, at anchor, cats are usually better than monohulls. The roll is reduced, although the pitch changes are more severe.

If you have concerns, it is better to try both. The quicker period of catamarans sometimes upsets stomachs more than the slower roll of monohulls, but overall, catamarans are better in this regard if this is an important consideration.

Our previous boat was a 37ft catamaran. We now have a 44ft mono. My wife was more prone to seasickness in the cat than the monohull. The cat motion was like sledging down a bumpy hillside. It probably improves as the cat scales up in size but small catamarans feel every ripple of sea motion as a quick movement of the hull. Our heavy deep draught momohull is far more comfortable at anchor in every way.
Modern monohulls suffer from high topsides forward that function like a sail. Veering at anchor is a common trait. We see lots of modern flat bottom monohulls rolling at anchor. Form stability has its place but for an anchored monohull it doesn't seem to work. I think our boat design works but I suspect it was more by luck than judgement of the original designer

[smj]

Originally Posted by Wandering1

Our previous boat was a 37ft catamaran. We now have a 44ft mono. My wife was more prone to seasickness in the cat than the monohull. The cat motion was like sledging down a bumpy hillside. It probably improves as the cat scales up in size but small catamarans feel every ripple of sea motion as a quick movement of the hull. Our heavy deep draught momohull is far more comfortable at anchor in every way.
Modern monohulls suffer from high topsides forward that function like a sail. Veering at anchor is a common trait. We see lots of modern flat bottom monohulls rolling at anchor. Form stability has its place but for an anchored monohull it doesn't seem to work. I think our boat design works but I suspect it was more by luck than judgement of the original designer

We’ve owned quite a few cats and there’s much more to a cats motion than size.

[malbert73]

Originally Posted by Wandering1

Our previous boat was a 37ft catamaran. We now have a 44ft mono. My wife was more prone to seasickness in the cat than the monohull. The cat motion was like sledging down a bumpy hillside. It probably improves as the cat scales up in size but small catamarans feel every ripple of sea motion as a quick movement of the hull. Our heavy deep draught momohull is far more comfortable at anchor in every way.
Modern monohulls suffer from high topsides forward that function like a sail. Veering at anchor is a common trait. We see lots of modern flat bottom monohulls rolling at anchor. Form stability has its place but for an anchored monohull it doesn't seem to work. I think our boat design works but I suspect it was more by luck than judgement of the original designer

This is key. Catamarans win in rolly conditions for certain. But the quicker motion especially upwind in chop can induce nausea. I personally prefer monohull motion underway in most conditions except for quartering seas in which case I have catamaran envy.

Re the OP’s actually scenario, it seems that the new generation of large volume monohulls sail and yaw a lot more at anchor, probably due to massive freeboard and windage forward, coupled with flat bottom.
My S&S designed Tartan 40 certainly has less interior space than new 40 footers. But even though it’s relatively light at 18K lbs, it is very still at anchor and doesn’t yaw much. I’ve been anchored next to newer monohulls and watched them sailing back and forth, snatching at the anchor rode at each turn. And we barely go back and forth. So, I assume this is because we have less windage and different hull volume underwater?

Now, put a beam swell into the anchorage and I wish we had 2 hulls

[rslifkin]

Some boats just have their quirks at anchor. My monohull powerboat has no pitch related discomfort at anchor (even though its pitch behavior isn't the most comfortable underway in a head sea), but especially if there isn't a lot of wind relative to the sea state, it has a seemingly magical ability to turn any little bit of wind chop into rolling, even when it's pretty much right on the bow. Flopper stoppers do help with this.

And as mentioned, yawing and sailing around at anchor is a problem at times (how much it happens depends on scope, how gusty the wind is, whether the dinghy is hoisted in the davits, etc.).

Yawing is a matter of where the windage is relative to the underwater drag. The more windage you have up forward, the more the bow will want to blow off the wind. Move the windage further aft relative to the stuff underwater and the situation improves with the boat acting more like a windvane. My boat has a lot of freeboard forward and the deepest part of the shallow, long keel is further aft, plus the props and rudders aft. So the drag in the water is aft of the windage, leading to yawing. In an extreme case I've seen boats tack through probably 120* and sail back and forth at anchor.

Certain wind conditions can affect yawing too, especially with a long, stretchy snubber or a rope rode. If it's very gusty (even worse with shifty gusts like nearby tall land can provide), the boat will stretch back in a gust, then rebound forward when the wind eases. Then the rode isn't applying much force to hold the bow upwind until the boat drifts back, so if the next gust hits too soon and is even at a tiny angle to the bow, the bow gets blown off and the boat flies downwind sideways until the rode goes tight and pulls the bow around.

[CarlF]

Having owned monohulls for 30 years I couldn't believe how good our 50ft Leopard cat is at anchor. Rarely a perceptible motion.

1: Heavy
2: Long waterline without much weight in the ends (reduces hobbyhorsing)
3: Foam core to kill wave slap noise
4: Anchor bridle with long legs to minimize swinging

With folding props and high quality sails it also sails as well as any cruising monohull I've ever owned such as the Discovery 55. Upwind 135 degree AWA and 110 tacking angle including leeway.

The cats that are uncomfortable at anchor tend to be under 45ft, high performance (e.g. light), and built of carbon fiber which is incredibly noisy at anchor.

[smj]

Originally Posted by CarlF

Having owned monohulls for 30 years I couldn't believe how good our 50ft Leopard cat is at anchor. Rarely a perceptible motion.

1: Heavy
2: Long waterline without much weight in the ends (reduces hobbyhorsing)
3: Foam core to kill wave slap noise
4: Anchor bridle with long legs to minimize swinging

With folding props and high quality sails it also sails as well as any cruising monohull I've ever owned such as the Discovery 55. Upwind 135 degree AWA and 110 tacking angle including leeway.

The cats that are uncomfortable at anchor tend to be under 45ft, high performance (e.g. light), and built of carbon fiber which is incredibly noisy at anchor.

Can’t fully agree. The most comfortable at anchor of the cats we’ve owned was our very performance oriented TRT1200, which is 6700 lbs and partial carbon.
The most uncomfortable was our first cat which had a narrow beam and high CG, almost chased us back to a monohull.

[PC45]

Perhaps this will help if you swing up to 180 degrees under anchor in fresh or hard wind. I have a friend who have tried an "anchorsail" 3 - 4 years and he is very satisfied.
https://lundhsails.se/ankarsegel



But it don´t help against rolling from side to side I think.

[hankstein]

Hands down... most comfortable boat at anchor is a trimaran...

I have had two (currently own a monohull) and with a bridle on the anchor they are much better than Cats. The most comfortable boat I've ever been on at anchor.