View Full Version : How many hulls ?


PsiPhi
02-02-2009, 01:53 AM
Hi,
I'm a newbie, just building a little skiff to learn to sail in.

Thinking ahead.
I'm planning on a small trailer sailer - take the family out for day trips or picnics, maybe some weekend trips with the wife.

Trouble is the family are a little apprehensive about sailing (or my abilities :o)
They say they'd be happier in a catamaran because (they think) they are more stable.

I thought, that makes sense, seemed logical.

There is a very good, active, yahoo group for Jarcats, which seem like a good option for a small home built family multi-hull. Trouble is, they all seem to tip their boats over, often more than once, and they are a bugger to right again.
Maybe they are just more experienced sailors pushing their boats to the limits?

Anyway, my question is, is a multihull really a more stable option for a novice sailors than a mono?
Biased opinions welcome, just tell me which way you swing (figuratively speaking).

Cheers

Simon.

alan white
02-02-2009, 02:22 AM
Multihulls in the smaller sizes are wet, wet boats. They do not need to capsize to make you look like you did.
Some monohulls are wet boats too, but many more are dry, whole season boats that you sit down in.
Stability is a function of crew placement on any small sailboat. The most important thing to tell your family is that everyone takes part in the operation of the boat, and those who don't will be in the way like so much dead weight. A multi is stable at rest, but they carry a huge sail relative to their weight and hence crew weight is less effectrive on them. In other words, they demand more skill to stay upright in a real breeze no matter how wonderfully flat they sail in modest winds.
The monohulled daysailer is not prone to digging in the leeward bow and tripping on it. Most importantly the monohull usually has lots of space to stretch out and room under the boom to switch sides easily.

PsiPhi
02-02-2009, 09:13 PM
Alan
Thanks for that, guess that was the conclusion I was coming to but it's good to know for sure, and why.

I can see how repositioning would be easy on a monohull, but I'm surprised you say they have more room to stretch out. The Jarcat I was looking at http://members.optusnet.com.au/rhturner1/j5-6.html looks quite roomy for a small craft (6m).
I loved reading about Charlie Fisher [NIS23] in AABB, but it really didn't look like there was much leg room in the cockpit?

Guess I'll start looking (plenty of time) at designs of monohulls that are stable family friendly designs.
From things I've read a flat bottom, straight sides makes for a stable hull?
Or am I mixing 'stability' with 'tippy'? or are the two inextricably linked?
Is a hull that 'bobs around a lot' more or less likely to actually go beyond it's recovery point?

alan white
02-02-2009, 11:17 PM
Usually, the small cat is a Hobie 16, which has a big trampoline with lots of space. The problem is not acreage per se but comfortable lounging space. Spend some time aboard one and you'll see that it's almost impossible to do anything but hang on. This is great for those who relish the speed potential of cats, but what about keeping the wife and kids happy? You need a place to stow a picnic basket or a thermos.
A daysailor can have a lot of usable room, and usable room is what I meant.
You mentioned the flat bottom type and the subject of stability.
Small sailboats, even keelboats, depend on crew weight to counter heel for the most part. Therefore, the differences between flat bottom types and round bottom types isn't so much about stability, but more about speed potential and handling characteristics.
A flat bottom boat pointy-bowed boat is generally called a skiff, and such boats are initially very stable. They sail okay, but also row and motor okay as well. This may appeal to you.
Round bottom types tend to sail somewhat better as a rule, as they have less hull friction. This makes them faster at lower wind speeds though both types are equal in heavy winds.
Multi-chine types fall somewhere in between, and if you build them, they are great examples of "most bang for the buck".
A good place to start if you are taking the family along, is a circa 15-18 ft centerboarder, either round bottomed (Daysailer 17) or multi-chine (Wayfarer), or even vee bottom (Point Jude, 19 ft Lightning class).
Flat bottomed boats are not so common any more, so you won't see many in glass in the size range mentioned. Not that they aren't good boats, just that the other hull types sail better in general (then again, Phil Bolger has made a career out of proving that box midsection boats are fast and faster than many more sophisticated shapes. To my thinking, they are ugly and structurally weaker than rounded shapes, needing more bulkheads, frames, stringers, etc..

PsiPhi
02-03-2009, 02:17 AM
One reason I look at flat bottom boats is that I live close to Morten Bay, S.E. Queensland. Pummicstone Passage in places has on 8~12 inches of water at high tide, but you may get to see a turtle, dugong or even dolphins.

Also you can beach a flat bottom for a picnic or afternoon on the beach. I'd like to visit some of the popular lake areas too.

If I can find plans for something not to complex, or expensive, I'd prefer to build out of ply myself. It's taken me about 8 months to build an 11ft skiff that other people have built in a week or two - I'm enjoying the process, what can I say. Building a boat might just turn out to be as much fun as sailing it.

alan white
02-03-2009, 11:09 AM
There are loads of great skiffs in the 18 ft range, usually old designs. Check out WoodenBoat plans.
nice thing is skiffs don't need much for plans. You need some drawings, but a skiff kind of builds itself. I suggest you check out Bolger stitch and glue designs for complete plan packages.
You can easily beach any small boat that doesn't have a deep keel, however. A larger boat might benefit from a flat bottom, but all small boats will be relatively flat underneath.
But for simplicity's sake, yes, the flat bottomed boat is easiest to build. As said, it is structurally weaker that a vee bottom or round bottom boat (hence a bit heavier all things being equal). But cheap and ultra simple to build, shoal, etc..

robherc
02-03-2009, 02:19 PM
There are also some (few) catamaran, or trimaran designs that have been designed to be more "family friendly." They are made to be drier, have more room, and be easier to keep upright than the Hobie style cats. The tradeoff, however ,is that they're not nearly as fast as their wetter siblings. (check out "Slider" for a decent example). If you look in the "Where are all the catamaran Innovations" thread, there are a couple posts (and a pic) from the designer of "Slider."

Also, in MANY situations, you can make a cat with better shoal draft than a mono...while still keeping some of your lateral stability ;)

PsiPhi
02-03-2009, 06:51 PM
Thanks again guys.

Alan, I have looked at some Bolger designs and even though I know little about boats I understand that they are well designed, and highly respected, but do I really want to go sailing in a cross between a clog shoe and a coffin (no offence intended).

Rob, good to hear a pro-cat view point. I'm still worried that they have a penchant for tipping over though. If I do go for a cat the Jarcat (see link a few posts up) is small, enclosed, easily built and trailed - they say. The designer lives within an hours drive of me and there are probably 15 or 20 being sailed or built within the same radius.
I read a lot on Jarcat group on yahoo, which is quite active - they do tip them over regularily though.
Is that likely to be a fault of the design, or just the way they sail them?

robherc
02-03-2009, 07:01 PM
Two BIG contributing factors to boats "tipping over":

1: Too much sail...and boat that's made with max. sail area for max speed is going to tip over...REGARDLESS of the design.

2: Sailing "on the edge." If you have too much sail up & pull the sheets too tightly, you'll be in for a spill. Any boat you choose, will be a LOT more "stable" if you use smaller sails..then you'll be less likely to tip it...but you can't go as fast.

PsiPhi
02-03-2009, 07:52 PM
..and that applies to mono hulls as well as multi hulls?
Mono's look a lot easier to get back right-side-up again too.
I do stress that I have no intention of 'sailing on the edge', or even going fast, but I am concerned about 'dumb novice syndrome', because I will be one.

robherc
02-03-2009, 08:50 PM
With either style boat, you will gain more "experienced stability" by reducing sail area. The most major difference between multihulls & monohulls for what I perceive to be your purposes, is that multihulls have extremely high righting moment (stability vs. capsize) intrinsically, whereas monohulls need some form of ballast (lead, water, steel, whatever). End result: Multihulls generally stay "flatter" on the water, and follow the movement of beam waves faster, while monohulls tend to rock more and need more draft for weighted keels (though some use water ballast instead for shoal draft).

I hope I've cleared up more than I've muddled here for you ;)

alan white
02-03-2009, 09:59 PM
"Alan, I have looked at some Bolger designs and even though I know little about boats I understand that they are well designed, and highly respected, but do I really want to go sailing in a cross between a clog shoe and a coffin (no offence intended)."

There are some georgious Bolger boats. In addition to his boxy boats there are real knock-outs. Look again.

PsiPhi
02-05-2009, 12:15 AM
Yes, I was a little flippant there, I've also been looking an Jim Michalak's designs, simple construction is one of my requirements, I was seeing box shaped boats everywhere.

I have looked at Bolger's other designs and I do LOVE the look of his Light Schooner, not what I'm looking for, but really good lines.

I apologise unreservedly.
It's purely asthetic, and the designs do grow on you the more you look at them.

I've also stumbled across the Vacatoner & Weekender, don't know how they would fare in Morton Bay, but they look really good, though I don't think they have the simplicity of construction I require.
Today I was looking at Michalak's AF2 and Normsboat. Again, don't know how they would perform in the bay or on coastal waters, or if they are just flat water boats - they quite light? They seem to use half the materials of, say, his Picara, which to a novice looks very similar.

alan white
02-05-2009, 01:32 AM
Those are simple sharpie hulls. Light and fast, but usually lacking self-righting ability. They don't sail well heeled over, preferring early reefing, but the construction is simple and the shoal draft allows beaching and sailing in shallow places. They make a good first build.
All good boats for near shore sailing.

PsiPhi
02-06-2009, 01:11 AM
Michalak has some similar designs that are multi-chine, but otherwise similar specification - gee's he seems to have nearly as many (though not as varied) designs as Bolger.

The multi-chine (Bobster, Fatcat, Toon2) ones look like they may be a little more complex to build, but maybe they are a little more forgiving on a novice sailor, or a little less scary to be in?


"There are some georgious Bolger boats. In addition to his boxy boats there are real knock-outs. Look again.
I did. If my first build is a Michalak, my second might just be a Black Skimmer.
http://www.nexusmarine.com/skimmer_home.html

messabout
02-06-2009, 06:40 PM
I can personally vouch for the Black Skimmer. I have sailed a Skimmer in Florida Bay which is treacherously shallow and can sometimes turn very ugly in bad weather. The Skimmer is the most efficient boat of it's type that I can think of. Bolger has contrived some exceptionally clever schemes for doing things. They are entirely functional and very economical in the build. I am thinking of Bolgers method of attaching the lee boards for example. A simple piece of rope does the job. Not only does it do the job but it allows the board to goose wing if you choose not to attend it after tacking. Way clever. Also the flooded forward and after compartments seem ridiculous at first thought. Flooding turns out to be a very smart thing to do. Some people think that Bolger is a nut case. Those people have never sailed a Black Skimmer. The sprit boomed yawl rig on the Skimmer is also a study in cleverness. Rigs of that type use the the absolute minimum of lines to pull or adjust. These sprit boomed sails are not the most efficient in the world but they are sure enough the easiest to deal with. The Yawl rig makes helm balance a simple matter. The Skimmer will sail miles on end without ever touching the tiller. Smart rig. and a cheap one too. If Bolger is a nut case he is a damned clever one.

johnelliott24
02-06-2009, 11:27 PM
I am a Tornado cat sailor and I build really fast cats and tris for a hobby who has sailed tons of different boats over the years. DO NOT get a cat. Buy something like a Flying Scot -- stable, dry, comfortable, unexposed....

robherc
02-06-2009, 11:57 PM
John:

Not all cats are racing cats (Re: "Slider" for one that I know is completed...I'm working on another, and I know of at least 1 other being designed to be dry, safe, VERY stable, and comfortable). If you design ANY boat to be a dead-minimal racing boat, it'll be wet; if you design it with extra reserve buoyancy, wider-beam hulls, and more freeboard, it'll be dry & spacious. Speak what you know, and remember that there are other avenues of design for the same # of hulls. If you build a cat with 20'LWL, 22/5' LOA, 9'BWL, 10'Beam, 2.25' freeboard, and 2' BWL hulls, you'll get an extremely dry boat! It won't be able to come CLOSE to keeping up with a Hobie 20 (or even a 16 for that matter), but it'll be great for comfort, dryness, protection, etc...there's more to design than cat=speed.

johnelliott24
02-07-2009, 09:59 AM
Good point, Rob. I was tunneling on the idea of someone picking up the newspaper and making the mistake of buying a Hobie 18 (like I once did) for the family. Tornados are even worse for families -- light days fine -- any wind and it is a constant cold shower. Two years ago I built a 22ft wave piercing cat to solve the wet problem. It is very dry, but is so fast (quite a lot faster than my Tornado) and exposed that it terrorized everyone (no issues or accidents, just the speed bothers them). Only my niece will go on it any more. As you pointed out, a day sailing tri or cat would be good -- quick, dry and easy to transport -- and not intense feeling. I've seen ads for a Magnum 21. Something like that looks nice, but my wife and family all like the look of monohulls. So after asking friends and family lots of questions we got a shiny, turquoise Lido 14. Everyone loves it, except I feel like a charter skipper even making sure to pack food and drinks for all. They all say "This is much better." But now I am looking for a Thistle so that we can all be dry and secure feeling while having a better and faster sailing boat. I plan to paint her vintage black with gold trim and have lots of wood inside with padded seats and drink holders. In the mean time I am just finishing my second foiling tri. Here is my first one. http://s371.photobucket.com/albums/oo159/johnelliott24/Precarious%20the%20trimaran/ Do not take the family out on this! My wife took one look and named her "Precarious!".

PsiPhi
02-08-2009, 08:56 PM
Thanks guys for some useful information and for sharing your experience, most valuable. I'm pretty sure I will go for a mono-hull, it was my original preference.

I'd still be interested to hear what the Catamaraners out there think of the Jarcat (J6).
They're a bit 'boxy' but are reckoned to be an easy build.
Small, light weight, easy to tow and shallow draft.
There is a lot of support and an active local group of 'Jarcatters' in my vicinity.
Only problem, they all seem to tip their boats over at some time.

http://members.optusnet.com.au/rhturner1/j5-6.html
http://members.optusnet.com.au/~ingle.m/jar1.html

View Full Version : How many hulls ?