Monohull or Multihull Sailboat?

[sneuman]

Originally Posted by ess105

The only comparisson that makes any sense is to ask; Under the conditions that would lead to a properly handled monohull heeling at 90 degrees - where would a properly handled multihull be and what would it be doing? You implied it would be heeling at 90 degrees. Perhaps you didn't realize this but a typical multihull would not be in the same place and even if it were, it would not be heeling at 90 degrees. The relevancy of your comment must be questioned as it was a meaningless comparison.

"Knockdown" is not the same as "heeling."

The first implies the result of large breaking waves that hit beam on; the second the result of carrying too much sail in more nominal conditions.

I consistently hear broad claims from cat enthusiasts to the effect "if you ever sail in a cat, you'll never go back." My posts are meant only to say that it ain't necessarily so. I have sailed both, and I prefer monos. We can argue whether one is safer than the other, but I know from experience how a heavy-keeled mono handles in survival conditions and I think I can reasonably infer how a multi might handle in those conditions.

[ess105]

Originally Posted by sneuman

I consistently hear broad claims from cat enthusiasts to the effect "if you ever sail in a cat, you'll never go back." My posts are meant only to say that it ain't necessarily so. I have sailed both, and I prefer monos.

Fine. Enthusiasts will say what they will and you have a right to your preferences.

Originally Posted by sneuman

We can argue whether one is safer than the other, but I know from experience how a heavy-keeled mono handles in survival conditions and I think I can reasonably infer how a multi might handle in those conditions.

But there you go again drawing comparissons without building the full picture. Why do you keep choosing to ignore the reduced probability of a multihull being in said position when you draw these comparisons?

[sneuman]

Originally Posted by ess105

Fine. Enthusiasts will say what they will and you have a right to your preferences.

But there you go again drawing comparissons without building the full picture. Why do you keep choosing to ignore the reduced probability of a multihull being in said position when you draw these comparisons?

Because there is no such evidence. Are you suggesting that catamarans are fast enough to escape bad weather? We recently had a thread on the subject (which I started) and I think the answers were inconclusive at best. Any skipper who bets his life on outrunning bad weather is making a fool's gamble, in my opinion. After all, Mr. Woods found himself in the thick of it in a catamaran. Now, how did *that* happen?

If, instead, you are suggesting that catamarans are less likely to broach (not to mention pitchpole - which we haven't even discussed), I'd say there's no evidence for that either.

Earlier in the thread we were told that cats don't get pooped, but Woods talks about being pooped in 20' waves and 40 knot winds - unpleasant conditions, for sure, but not yet extreme.

The bottom line is that there's nothing in the multi hull form which makes it immune to the laws of physics. Monos and multis will experience the same conditions at sea. How those hull forms cope with said conditions, and what limitations if any their designs place on their crews, are separate issues entirely.

[Steve Rust]

I think the whole comparison is just not valid. Two different types of boats that have vastly different levels of initial stability. Lets be clear that knockdown and capsize are two differant things. This graph is from Chris White's book "The Cruising Multihull" and values are drawn from three real boats of normal form 50 feet in lenght. I would consider a multihull "knockdown" to be when it starts to pass it's maximum level of stability around 200,000 ft lbs of force and 10 degrees for the cat and 170,000 ft lbs and 25 degrees for the tri. The monohull never developes more than about 65,000 ft lbs of righting force, that's why self righting is so important. What would be considered a "knockdown on a multi is not the calamitous event that it may be on a mono. Your windward hull may start to lift on a cat or the main hull on the tri but you still have control and it's a stern warning to slow down and reduce sail. The monohull guy can point to the part of the graph beyond 30 degrees where the mono is starting to develope maximun stability and the mult is losing it but you have to get beyond 50 degrees for them to be about the same. Beyond 50 degrees the multi has less but you have to take into account that to get to this point you have to get past the high initial stability "hump" nearly three times that of the monohull.

As far as broaching I can't point to any chart for evidence but my own experience shows me that my Searunner has very little tendency to broach. We have run her dead downwind in 25-30 knots with 6-10 foot waves at 10-11 knots on autopilot as we were cooking and eating supper. Ran straight as an arrow. Try that on your monohull. I dont' have any experience with cats but I would think they would behave themselves too. It's the narrow hull form without the big keel and lack of heeling that does it.

[Steve Rust]

From the last page of Jim Brown's book "The Case for the Cruising Trimaran".

[44'cruisingcat]

Originally Posted by sneuman

Because there is no such evidence. Are you suggesting that catamarans are fast enough to escape bad weather? We recently had a thread on the subject (which I started) and I think the answers were inconclusive at best. Any skipper who bets his life on outrunning bad weather is making a fool's gamble, in my opinion. After all, Mr. Woods found himself in the thick of it in a catamaran. Now, how did *that* happen?

Like most mono people who deride multihulls, you are basing your opinion on a very few instances of what are often outdated designs, or designs intended for coastal cruising, which get into trouble on ocean passages. Having said that, Richard Woods' boat survived perfectly well without him. In fact if he hadn't been "rescued' from the boat there would be no story to tell at all.

Originally Posted by sneuman

If, instead, you are suggesting that catamarans are less likely to broach (not to mention pitchpole - which we haven't even discussed), I'd say there's no evidence for that either.

Evidence? What evidence do you have that in the situation where you were knocked down a catamaran would have capsised? You have none because there is none. In fact at 90' monohull would be producing around 25% of the righting moment a similar sized multi would at 5 degrees.

There is, however, a huge amount of anecdotal evidence that multihulls are less prone to (or even immune from) broaching.

Originally Posted by sneuman

The bottom line is that there's nothing in the multi hull form which makes it immune to the laws of physics. Monos and multis will experience the same conditions at sea. How those hull forms cope with said conditions, and what limitations if any their designs place on their crews, are separate issues entirely.

Interesting that you bring that up. In Dick White's "The Cruising Multihull" he refers to a study done by the US military on the effects of rolling motion on a crew's capabilities. If there was ever an argument in favour of multihulls that is it. On a multihull the crew will be several times more comfortable, capable and safe than on a mono.

[cat man do]

Originally Posted by sneuman

"I consistently hear broad claims from cat enthusiasts to the effect "if you ever sail in a cat, you'll never go back." My posts are meant only to say that it ain't necessarily so. I have sailed both, and I prefer monos. .

My partners Boss reckon's the same.

Rent's the same bloody Beneteau in the Whitsunday's every year and all we hear is how bloody good Beneteau's are ( he has vast experience in different boat's NOT)

One year we convinced him to go to the dark side and charter a Multi and suggested maybe a Fusion 40, Grainger 40 , Lghtwave 38, from these guy's Whitsunday Bareboat Catamaran Charters Australia- Luxury Catamarans

Instead he got an Elite 40 , not from these guy's but from some other crowd The Elite 12 Bareboat Charter Sailing Catamaran

Naturally it sailed like a brick, and now all cat's are dog's in his eyes.

I think this is how a lot of people get there impresion on multi's from, sailing on less than responsive design's

Dave

[44'cruisingcat]

I should correct myself here - the Author of "The Cruising multihull" was CHRIS White, not Dick White as I said earlier.

[md7a]

Originally Posted by delmarrey

Sometime take a cruise on a fullsize Cat in a nice breeze. And as far as ocean crossings, most of them are delivered on their own bottoms. Ya just have to learn how to sail them, just like any other vessel. All vessels have their limitations and learning how to manipulate it's advantages is what seperates the pro's from the lackies. Quality is a must!

I find myself drawn to a definition of seamanship penned by Captain
Lincoln Colcord, a ship captain from Maine. Having spent his life at
sea, Captain Colcord defined seamanship as "an attitude and way of life,
which face facts, which deal in realities without evasion, which know
that the only failure is dishonesty and that error is truth betrayed."

I think Capt. Colcord's maxim could meaningfully be applied to a somewhat broader spectrum of human experience than seamanship - though it's an unquestionalbly eloquent and elegant insight. Thanks for posting it.

[schoonerdog]

Regarding broaching, there were two points. One was that it was very unusual, which it is. I went off watch on our old PDQ 36 and my wife remarked that we were sailing at 12-14 knots. We had just gone between two islands and got subject to a rough wind and seas and I looked back to see a wall of water coming at us (I couldn't see the top of it from underneath the bimini but I would guess at 14 ft). As it was shallow it was square shaped wave. Our boat lifted up on it immediately as it broke and about a half a gallon actually went into the cockpit. I know lots of multihullers with the same experience. Of course it could happen, but it's not common. The second point on drainage was the drainage is larger and more direct than any monohull could allow. It's not boastful or unfounded, we simply have cockpits that sit a couple feet above the water and allow huge drainage directly down. Our particular boat has two 3 inch through hulls in the forward part of our cockpit and a couple 1 inch drains in the aft portion of our cockpit. Each of the forward drains would allow around 60 to 100 gallons of water out per minute, so 120 to 200 gallons per minute drainage. Our cat also doesn't have engines aft, but in the center, so it presents very light hollow transoms which can lift easily.

[Kanani]

I have delivered many-many boats of all different designs, all over the world. I've also cruised my own vessel (Passport 45' ketch mono-hull) for 14 years.

I have only made one ocean passage delivery on a Cat. I found the Cat to be extremely "different" in the comfort level at sea (mixed bag). I think that one could get used to it but I found going to weather extremely uncomfortable and wet. However, I found being up-right and not having to contually be fighting the forces of nature, rather pleasant (at times). I will say that I felt a little "Beat-up" when I got off of the Cat vs momo. That could merely be a matter of conditioning though.

The safety issues are mute and argueable 'till the cows come home. The only safety issue that I found a little concerning is the amount of stress that is put on the mast and rigging. As a mono-hull heels, it releaves stress on the rig. The loads on a multi-hull rig are tremendous. The jaring forces on the rig are far worse on a multi than a mono. I don't consider that dangerous as long as the sailor is aware of this fact and the rig is carefully designed and maintained.

Now I will tell you something that may surprise some. Cruising is +-10% sailing and +-90% sitting at anchor. I think that some people pass up the livibility apects of a Cat in an unbalanced manner. As far as livibilty, I would select a well designed Cat every time. After-all, one must look at these things in balance. 90% of your time cruising is an important aspect to consider IMO.

I think that some people dwell on the technicalities of encountering the "Perfect storm" a little more than they should. It borders on paranoia at some point IMO. Making safe ocean passages is certainly important, however, I believe that a well maintained Cat (with special attention to the rig) will do as good a job as most mono-hulls. I would also carry a Parachute storm anchor on any multi. Running down-wind, in heavy seas, does not have to be an option. Lying to a parachute for some hours can certainly be a comfortable and safe option for any vessel.

I have made many long passages in the same fleet that contained multi-hulls. Passage length is usually the same unless there is a Cat along that is really not fit out for cruising. Weight makes a huge difference in passage making on a multi.

I am thinking that my next boat may well be a Cat.

[44'cruisingcat]

Some very good points. IMHO The 10% v 90% figure is possibly conservative. Most cruising boats probably spend less than 5% of the time actually sailing, and probably never even see a real storm.

Multihull rigs do experience greater loads, but they are designed with that in mind. They do need to be maintained, but then so do all rigs.

My experience with going to weather was that it was much more comfortable (to me) than on our monohull, and while there was plenty of spray flying around, the cockpit was dry enough. Our mono doesn't have such a well protected cockpit. In 25 - 30 knots going to windward for days, we had a tupperware tub of sweets sitting on a table and they stayed there. Admittedly, cups of coffee wouldn't have though.

I hadn't been sailing prior to that trip for a few months, and didn't get seasick. I know for certain I would have been at least very queazy in the same conditions on our mono.

[Tropic Cat]

Kanani , When it comes to rig loads, you are of course correct. We don't heel, so the rig doesn't unload. I don't know which cat you delivered but I do believe that all cats have much larger spars. I know that my mast and boom are considerably thicker than any monohull anywhere near my size. Rigging is also sized larger and rigging attachment points are well considered.

As to your next boat .... Welcome to the "dark side" .... which does seem to be getting considerably "lighter" these days!!

[Kanani]

Originally Posted by rickm505

Kanani , When it comes to rig loads, you are of course correct. We don't heel, so the rig doesn't unload. I don't know which cat you delivered but I do believe that all cats have much larger spars. I know that my mast and boom are considerably thicker than any monohull anywhere near my size. Rigging is also sized larger and rigging attachment points are well considered.

As to your next boat .... Welcome to the "dark side" .... which does seem to be getting considerably "lighter" these days!!

Well Rick, I notice that you are in Florida. The US East Coast and Bahamas may well be my last cruising grounds. I spent a year going from MD up to Nova Scotia, then down the ICW to Florida and over to the Bahamas. From there, I headed to Panama.

I could see myself spending many years just cruising the East Coast and gunk-holing in a Cat. It would be nice to have the extra room and not having to be concerned (as much) about the water depth.

[Therapy]

Originally Posted by Kanani

I could see myself spending many years just cruising the East Coast and gunk-holing in a Cat. It would be nice to have the extra room and not having to be concerned (as much) about the water depth.

My plan!!!!!

At least to start.