build a wharram or a Prout 37?

[jah]

I have plans for a tiki 30 wharram cat.

I have access to Prout 37 moulds.

Which should I build?

I can get half price epoxy and glass cloth, but only regular price polyester resin.

I have no plans for the Prout so don't know where to lay up extra thick for high stress areas. Prout recommend kevlar in some areas, but I don't know where.

** Anyone have an idea on time to lay up moulds for a 37' cat?

Tiki 30 is about 900 hour build.

[rwatson]

Wharrams were designed with economical usage of Ply sheets using relatively unsophisticated building skills.

If you havnt built in large fibreglass moulds before, you may get a better result.

Personally, I think there are far better ply designs in cats than Wharrams, in space, performance and ease of building these days.

[jah]

Thanks for that.

I also have plans for a 24' woods cat, but didn't find them as easy to follow as the Wharram ones. And the finished article didn't look as safe (e.g. beams)

Which other designs do you have in mind?

Trouble with Prout is that think the boats are more like floating caravans.

[rwatson]

For ease of building, looks and space I find it hard to go past the older Kelsall designs

eg
http://www.duckflatwoodenboats.com/m...gallery?KID=49

The building method is very simple, the finished product is very capable and the configuration with the centre Pod is a great concept.

I was very keen on the Wharram TIKI designs till I actually got on a finished boat, and found that the accomodation is like a shoebox because of the sharp hullside angles. The PAHI range was an attempt to cure this I am sure.

The other "downer" for me on Wharram cats is the manauvarability. With the fore and aft symetry of the hulls (stern and bow the same shape), turning and steering is very ordinary - not usefull for racing, or working your way through a busy marina, or other confined spaces.

[jah]

Thanks again.

I didn't realise Kelsal did wood as well as the KSS method.

I see what you mean about accom space in the Kelsal designs.

Cheers

[marshmat]

Attached images:
the Prout 37, see http://www.multihulls.uk.com/gbrokerage/prout37_1.htm
and the Wharram Tiki 30, see http://www.wharram.eu/photos/index.c...e=DSC00497.JPG

The Wharram is a much smaller boat. For interior space, the Tiki 30 would more commonly be compared with production 25-26 footers. Wharrams are simple boats, for a simple lifestyle. I think I'd be happy with one of his 30- or 40-something footers, but some folks accustomed to having lots of space will likely be disappointed. I've heard good things about the Tiki rig- it's a little weird, with the luff pockets and huge gaff, but owners seem to like it. I wonder if leeboards or something would help it to windward.... Wharram seems to insist that the V-hulls can go to windward on their own, but this opinion doesn't seem to be universal. For a Wharram of comparable size to the Prout 37, you'd be looking at the 40' Tehini, or maybe the Tiki 38 with deckpod.

The Prout's deck cabin looks rather boxy, and I worry about the windage that will add on a boat this size. It strikes me as more of an island hopper, less of a passagemaker.

rwatson's suggestion of a Kelsall sounds like it's worth investigating. The Kelsall 27 Trail and 34 Southern Ocean would be near the top of my list if I were looking for a cat of this size. (Again, because of windage and sheer ugliness, I'd skip the full bridgedeck until you get to 40 feet or so.)

[rwatson]

Originally Posted by jah

Thanks again.

I didn't realise Kelsal did wood as well as the KSS method.

I see what you mean about accom space in the Kelsal designs.

Cheers

The good news is that the "KSS method" applies to the "old" designs as well as the "new" designs. Its no black magic. You simply lay ply (or foam in the new method) over fibreglass on a smooth table the length of the boat, and produce a mirror smooth 30 foot hull side, bottom etc. You then attach the stringers, and lay the whole lot on the inverted frame, and epoxy the joins.

The amount of finishing/filling/fairing/painting that this saves over conventional methods is amazing - the finishing is always the major headache on ply boats.

[david@boatsmith]

Wharrams estimate of construcion time is off by a factor of 2-5 depending on finish quality. You can see step by step photos and comments at www.tiki30.blogspot.com This boat was built to a very hihg level of finish and has 4ooo + hrs involved. On the other hand the Tiki 30 sails very nicely indeed. It has very narrow waterlines, is very light, and is not as proportionatley under canvassed as many of Wharrams designs. David www.boatsmithfl.com

[Ilan Voyager]

The 2 designs Wharram and Prout are antics. Compared to cars, it's like building a 1935 car. Happily, multihull design has evolved since these 2 boats which are also rather poor performers.

The Wharram is a cramped pipe inside and hydrodynamics are... I won't say the word we are in a decent forum. The Prout with the small mainsail and the big jibs is a pain to sail.

I would spend my money and work on a better boat. There are a lot from Kelsall, Hughes, Lerouge, White and many other designers.

About the methods you have the choice:
*-"placo-plastic" (flat panels of GRP made on a table and ployed in a female jig or on male bulkheads) an old method as I have seen it in a french shipyard in 1978, and described in the special Loisirs Nautiques on polyester - around 1980- and the variants Kelsall and Hughes (surely there are others),
*-mix of plywood and strip plank
*-cylinder mold by Hughes
And surely many others.

Have not illusions building a boat implies many hours of work.

[Manie B]

Hi Ilan

The Prout with the small mainsail and the big jibs is a pain to sail.

as a matter of interest why do you say that?
is it a problem of weather or lee helm or perhaps something else. Wind direction perhaps?

I dont have personal experience of this that is why i am asking. I was told that it works well cruising as often in light winds only the genoa gets employed and then in heavy winds only the jib. My interest is cruising and not racing.

The link supplied with the Prout pic in post#6 is very interesting as that particular boat "Phanta Rhei" was sailed for approx 10 years long distance.

I personally dont like Prouts because of the "old" design incorporating the middle "hull" which must slam a lot and slow the boat down a lot. For a 37 its design is finished.
Wharrams are for 60's hippies that did not understand or know of skin cancer.

I am an Easy fan and i suggest to a potential builder to rather go that way - far greater chances of success.

Anyway Ilan it would be nice if you could give a bit more insight into the sailing ability of the Prout

[Manie B]

Sorry i forget the old Dean 35 also had an "aft mast" setup

[Ilan Voyager]

Yes Manie I'll give you some insight:

-The Prout cats are heavy, very heavy and you need a good breeze to begin to move them. Otherwise you'll use the engines. And it's sloooooooww.

-I've noted a tendency to pound with horse hobbying.

-A XIX century clipper with worn sails has a better pointing ability...

-Big jibs mean big winches and/or a lot of physical expense to tune and tack. Big jibs are very sensitive to any change of speed and to pitching.

So add all these factors and imagine going upwind with such a boat. It's a pain.

The best combination on a multihull is a big fully battened mainsail, an easy to tune sail and a small self tacking jib. So you control the boat by just the mainsheet; it's fast, effective and secure. You can even have a releasing mainsheet device controlled by an inclinometer. A big gust of wind, or going too windward lifting a hull and you release the main sheet, de-powering the main sail.

Now try to do that with a jib, a genoa, and a mainsail at the same time...big panic

And try to make several tacks shorthanded with jib, genoa, and mainsail... Do the same thing with a big mainsail/small jib you have just to push the tiller...

[marshmat]

I didn't realize Prouts were all that heavy. Perhaps when they're giving displacement figures, they're quoting them in light-ship condition? I can see how adding a couple of tons of fuel, water, gear, crew, etc. to a Prout that weighs five or six tonnes bare would slow it down a fair bit....

The pounding, I presume, comes from the low bridge deck clearance that some of these cats use in order to get a standing-headroom saloon up there?

How about a non-overlapping jib, self-tacking, on a club? And what about the sheet loads from the huge, roachy main? I've never sailed one of these boats but would love to hear more.....

[Ilan Voyager]

Matt Marsh

Most of the shipyards give light displacement weights... Prout cats are heavy. Yes, pounding comes from of the low bridge deck clearance and rather poor hull shapes that lead to a rhythmic pitching that spills out the wind of the sails.
Also not very good for the stomachs...

Fully battened mainsails are controlled by the following means:
*-compression in the battens. We can neglect that on a cruising boat, and take a given compression.
*-tension in the front part of the sail. Sorry I do not remember the word in English. In French it's the "guindant". Good to flatten a sail.
*-rotation of the mast (if rotating mast) by a lever (called in French "arthur") you can over-rotate or under-rotate the mast; the bending characteristics of the mast change and thus the shape of the sail. Not essential on a cruising boat.
*-tension in the aft part of the sail (luff?, in French "chute"). A higher tension straighten the aft part and gives s fuller sail. Too much and you may "close the sail".
*-lateral control, ie angle of the sail.

Full battened mainsails do not need an enormous tension as they are shaped by the battens and are pretty tolerant. With a good hoist and eventually a winch you can control the tension until 80 m2 (about 860 sq feet), the small hoists of the traveller permit to control the angle sail.

If you use a wishbone, you need only a 4/1 hoist and the traveller is not mandatory. It's easier than controlling a 80 m2 genoa...A genoa puts a lot of compression in the mast, with the engineering problems implied.

[marshmat]

*-tension in the front part of the sail. Sorry I do not remember the word in English. In French it's the "guindant". Good to flatten a sail.

guindant = luff, thus I think you're talking about the tension on the main halyard?

I guess the thing that I find a bit intimidating about a big, full-roached main (keep in mind I've never sailed such a boat) is that, in a good breeze, it would appear that the sheet loads would be pretty high, and thus the sail could be hard for shorthanded crews to manage without a lot of big winches.

Some of the cats I've seen just use two mainsheets (and sometimes a preventer)- perhaps a traveller is the way to go then?