Best hull design for comfort at anchor?

[caribbeancruise]

My wife and I have been cruising on and off for the past 8 years and have spent the last 18 months on the water almost full-time.

We recently sold our 2010 35’ production boat (monohull, fin keel, spade rudder, flat bottom, carries width of the beam all the way aft, high topsides). As we’re looking for our next cruising boat, oddly, one of the most important things at the top of our list is comfort at anchor in high winds.

While cruising for 3 months in the Bahamas earlier this year, we found ourselves staring out of our portlights in one storm after the next wondering why we were healing at anchor and swinging almost through 180 degrees. We could dampen the swinging a bit by running a bridle to an aft cleat, but we’d still swing at least 45 degrees on either side of the wind. Sometimes I’d even put out a sliver of jib and countered with the helm hard over to one side trying to lay ahull, but still, just barely a measurable difference.

The cats in the anchorage looked like they were having a comfortable time and barely noticed the frequent 20-27 knots winds.

We thought, ok easy choice, we’ll get a cat. But, after talking to owners and watching several videos of different anchorage scenarios, we’re not sure that is the answer. They seem to bounce quite a bit in a short chop while at anchor. Most didn’t seem to swing much, though there were a few that did.

We also noted that we never encountered these issues on our 1991 30’ Tartan even when winds reached up into the low 30’s. Our memories could be short though; maybe we just didn’t worry as much about it.

If comfort at anchor (defined as less swinging so we’re not going beam on to the wind and waves every few minutes) was the top priority, would a better hull design be the answer? Or is a heavy cat the easiest solution?

This seems to be a tough, subjective question, one we haven’t been able to answer after cruising on and off for 8 years. Maybe Paul and Cheryl of Distant Shores have it figured out? The hull design of their new Orion 49 seems similar to their Southerly (1-3) in many respects.

Please share your experiences, boat model, wind conditions - good and bad.
Thank you!

[TeddyDiver]

Narrow water plane area and heavy displacement works against wave action. Wind, if the sea state allows, anchoring from the stern stops almost all swinging. A cutter, cutter ketch or schooner have more windage aft and behave better when anchored from the bow, also a bridle helps as does rigging a trysail.

[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

[caribbeancruise]

Thanks! We should have tried the stern anchor, there were definitely a few times when we had the anchorage to ourselves and wouldn’t have to worry about not swinging with the tide. I was wondering if a narrower, heavier hull design would help. Maybe an Island Packet with full keel and a shallower draft makes sense. Does the length of the keel (full, 3/4, or fin) make much of a difference?

[caribbeancruise]

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

I saw a similar boat try that. It seemed to dampen the effect a bit, but not as much as I would've thought. It'd probably take a bit of experimenting to get the right size in the right location (position on the stay), but definitely worth a try. Thank you.

[noelex 77]

Welcome to the forum Caribbeancruise.

Yachts are inherently compromises. While I may not place such a high priority on this specific feature, it is your vessel, so here is my response in order of priority for a monohull:

* Displacement
* Beam
* Length Waterline (LWL)
* Draft
* Windage
* Windage aft compared to windage forward
* Sound insulation
* Ballast ratio
* Absence of stern overhang
* Thickness of the anchor chain relative to displacement

Additionally, there are techniques that can substantially enhance comfort at anchor, but the above list pertains to the yacht’s design, which I believe was your inquiry.

In challenging anchoring scenarios, the utmost comfort is derived from unwavering confidence in your ground tackle. However, this is a separate topic.

[gr8trn]

Following for sure. As you ruled out a cat I want to read what is being recommended. I am glad to know there are others that are not going to automatically get a cat to make anchoring the most comforting.



Interesting you bring up Distance Shores III. I don't know about the new boat's keel, isn't the Southerly a lifting keel and not a centerboard? If so, I would imagine when all that keel is lifted and all that righting moment is lift up such a boat will be quite wobbly at anchor, no?

[JPA Cate]

Hi, carribeancruise,

Here are some of the easier things we've done to stay comfortable in anchorages:

1) line from aftmost cleat to anchor rode, and veer out another 10 ft or so of chain, to swing the stern to the incoming swell that refracts around headlands

2) stern line out by dinghy to hold bow into waves (Our boat's bow is pretty blunt, and is very fine forward, so the bow will go down, but 44' waterline with 46' on deck, and wide flat stern won't go down very much at all.)

3) take out a 2nd anchor to windward, so you lie like the tail on a "Y". Mostly only do this where we have dragged, due to a soft bottom. Usually, it works as desired, for this boat, haven't done it in anything over 65 kn. sustained.

4) friend does this: small parachute anchor, draped off the bow. Their boat is 15 m., narrow beam, fin keel, skeg-hung rudder. Cutter rig with both headsails on furlers, so a lot of windage forward. He reports it quiets down VERY well. Another acquaintance, used his 2nd anchor that way, to just drag while the bow tries to blow off.

Principles:

If you can make do with a single anchor, do so, because it is always easier to leave the anchorage.

Sleep on the settee amidships if it pitches "too much". Sometimes those mischievous thugs, the weather gods, do want to stir us up.

For us, we learned to tolerate a fair degree of motion at anchor and not have it disturb us, but if there is long fetch, with a frontal passage's wind shift predicted, then sometimes, going to sleep with it bumpy is okay if you do it knowing the shift and attended calmness is coming. For all the advice of dealing with what you have, not what you expect, yet anchoring on the lee shore before the shift has worked very well for us. Success depends in large part on how reliable the forecasting is for the area. Over about 45 knots, I get nervous, and may stay up waiting for the change to start.

Jim mentioned a riding sail. A boat in our anchorage here, has been flying its riding sail part of winter and all spring and summer is here, by local standards. It is one of the wedge shaped ones, and the boat, a Deerfoot, lies happily, bow into the wind and does not dance around like we do.

Hope this helps.

Ann
lying Port Cygnet, TAS

[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.

[Jim Cate]

^^^^

Chotu, I believe that "rocker" refers to convex curvature of the hull in the fore and aft dimension, not side to side, and has nothing much to do with rolling at anchor. Hobby Horsing, yes, rolling, no.

Jim

[arsenelupiga]

from our now 11th year on our lagoon 400, this was statistically significant regarding topic you interested in.

when thing got rough in anchorage (many times) , monos left first, then cats then lagoon cats left last or not at all. So yeah, heavy cat is the answer based on that stat. however ensure bulkheads integrity else you will hear cracks and not be happy.

[Chotu]

Originally Posted by Jim Cate

^^^^

Chotu, I believe that "rocker" refers to convex curvature of the hull in the fore and aft dimension, not side to side, and has nothing much to do with rolling at anchor. Hobby Horsing, yes, rolling, no.

Jim

absolutely correct, of course. Yes. Rocker is fore and aft. So when I said rocker, I was referring to the fore and aft curvature. That's why a boat with a lot of rocker rocks at anchor in a fore and aft direction. As in, the bow goes up and down. Hobby horsing. The natural shape of the boat causes that to happen.

and if you look at most boats the other way,from the stern, the same type of curvature exists running athwart ship and is even more exaggerated. That's why they rock so badly when waves are coming from the beam. the only thing preventing them from being worse is the keel. that gives it some resistance to the rocking (in both directions)

but an entirely different situation is form stability. a couple land examples. A motorcycle does not have form stability and relies on balance and rocking (leaning) for stability. A car does have fom stability. The shape of the car is what makes it stable around a corner. it’s the same for certain boats.

A flat object that spans the wave crests does not pitch at all. Take a look at that really rudimentary drawing I made. That shows the exact point. You can clearly see the top one is not going to pitch or hobby horse. It has no rocker. There will be no pitching of the bow or stern. multiple wave crests support the entire hull evenly and it stays flat. That’s how my boat works in those conditions.

[Chotu]

Originally Posted by Jim Cate

^^^^

Chotu, I believe that "rocker" refers to convex curvature of the hull in the fore and aft dimension, not side to side, and has nothing much to do with rolling at anchor. Hobby Horsing, yes, rolling, no.

Jim

and Jim, if I understand your boat as well as I think I do, it is more immune to hobby horsing for these very reasons. Your bow probably doesn’t pitch up and down as much at anchor as some other design designs would. I am imagining your underwater profile looks more like a racing boat with less rocker

[Peeew]

My boat is a design that tends to sail at anchor quite a bit. I find that a riding sail on backstay or boom lift reduces the angles almost in half. Also I often use “sidewings”, large isinglass windows in canvas frames that zip to Dodger, connector, and snap to toe rail. This seems to be enough windage aft to help also.

[caribbeancruise]

I was initially thinking our solar arch and dinghy would provide enough windage aft, but in hindsight, that is pretty negligible in comparison to the bow and roller furling. Dragging a second anchor or small chute from the bow also sounds like an interesting idea! Live and learn, wish I had asked the question before spending a season in the Bahamas! This year will now be much more comfortable no matter what boat we end up on thanks to all of these great suggestions.

We're leaning towards a "newish" cat 2008-2017 - each one seems to have it's own set of documented issues. Like arsenelupiga mentioned, we'll look at the bulkheads on the newer 39, 40 and 42 Lagoons carefully (the 450 is beyond our budget). Would love to find a newer Garcia, Ovni, Besteaver or the like, but they're also beyond our current budget. That'll be a topic for another thread .