Help me choosing right design

While a Classic doesn't require a epoxy build doing the sheathing and coating will make the boat as long lasting as any build. Epoxy for the glue then makes sense too. It is a lot less epoxy than any tack and tape boat using large fillets requires.

 

Is this really the case? I havnt personally compared the 2 construction methods but if I remember right the classics have a lot of faying surfaces when you consider laminating the stems and backbone, stringers to bulkheads, skin to frame etc, im not sure there would be a lot of difference assuming you are going to sheath with both methods. I don't care who designed a boat, a stringer on frame Woods or Kohler or whoever or a stitch and glue of like construction is going to use a like amount of material as a Wharram of a comparable size.

Steve.

 

I worked it out for boats in the larger sizes using 36' Raka plans I got from Paddy and comparing to similar size tiki 38 builds which also use stringers. It does add up...Using the Gougeon book we can estimate the square footage per pound of resin/catalyst for glueing compared with the coverage for coating and sheathing as well as amounts used for fillets. The Tiki keel join takes a lot of epoxy and doesn't offer the protection of the laminate timber keels in thin water. I call it the "skills versus squeegee conundrum". Better fits on the classic = less gap filling glue. If you live where timber is expensive this might change the result but timber is renewable while most epoxy is currently oil based.

 

Essentially I agree, 100 sheets of plywood and 100kgs epoxy cost the same whoever the designer is. However, the "Classic" Wharrams used stringers set flat, so much less stiff and used twice the glue as a stringer on edge. And they had solid beams which also wasted material for no real benefit.

I assume when Cav did that pricing he was comparing a Classic Wharram with a Tiki, rather than comparing it to another designers boats.

The Classic series were all designed before epoxy glues became popular, so were built using resorcinol glue and the recommended sheathing was Cascover.

Disclaimer: I never built a classic Wharram, but did sail the Hinemoa, prototype Tangaroa mk4, Oro, Narai, Tehini (which I sailed across the Atlantic) and did a lot of work on the prototype Pahi series as well as help refit Tehini (then on its third set of beams in 8 years)

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Yes the comparison was between the Wharram designs only. I agree about the beams but have always thought the Wharram Classics were just a starting point for development, nothing wrong about resorcinal glue if the fits are good. The toss up on the flat stingers is they take up less interior space, important for a V hull. Definitely there are places to refine the construction but they are pretty well suited for uninvolved banging away with the hammer then going sailing. To be sure they use about the same amount of glue as any other designers stringer/frame boat.

When I carved up the Searunner 31 it was surprising how heavy the fiberglass chines were and the amount of resin they used. Definitely a place where the basic skill of beveling a chine would save enormous amounts of glue and weight. I'd encourage the skill set myself. A method touted as so easy any bone head could build it sort off implies that only bone heads are building boats......but once you factor in the effort and time of building perhaps there is something to that.

 

agreed, it's stronger than epoxy. And it is similar to the glue used in making plywood. But as you say, it isn't gap filling!

Richard Woods

 

Yes, those big flat stringers and all the laminations are what I meant by a lot of faying surfaces to be glued, while they were originally built with resorcinol ( I agree, a better wood to wood glue with good fits) if a classic were built today,most would be built with epoxy and sheathed with epoxy and consume a lot of it.

 

Richard,
No offense man, but only your Eclipse design look cool enough. I cannot spend so much money without my wife's approval (very sad) and I cannot convince her that your designs are good when they look so outdated.
Eclipse seems OK, but it is strip planked, which I want to avoid. I am scared of this "strip planking". It seems pretty hard and time consuming for me . Probably expensive too.

It turns out that Schionnings does not sell Cosmos 930 any more.
Plans for Wilderness are designed for their kits and price is so high that I have ruled them out.

Coral cove for now is ruled out too because of the design ( raked bows mainly and low headclearence).

So my very short list now is Waller 1100 and Roger Hill 10m plywood cat.
Of course I am open to any other offers.
It turns out that I can start actual building no earlier than September, so I have plenty ot time.

 

There are looks and then there is how a boat works. With your bridgedeck requirements I'd build a Vardo because I know how Richard's boats sail. Function does dictate form. You'll probably find everything takes a similar time to build if you don't have much experience. The outfitting and interior are where the time lies. Hopefully your wife is willing to roll up her sleeves and work to help finish what her sense of style requires, if she does there are many of us that want to know if she has any sisters!

 

Pick any two

I have to agree that fast, cheap and comfortable (full headroom) are incompatible aims. My contribution to this debate is based on 10+ years with a strip-planked Simpson 30' cat and a couple of years with an (also strip planked) 22'Tri both of which I built myself.

You will find the accomodation on any small tri impossible to live with,other than for a couple of days a a time.

Forget Wharrams unless cost i your only real criterion - the headroom doesn't exist

You have plenty of better options with a cat but as others have advised, forget full headroom on the bridgedeck for anything under about 40' unless you want it to look like a truck. You can certainly have this in the hulls. A solution I used very effectively is a raised doghouse - it looks good, provides headroom when entering and movng between hulls and gives cover from the weather while a the helm. Overall though,the Simpson design looked"old fashioned" even if his boats are fairly easy to build and have a good seagoing reputation. Try the Tomcat32 I don't know much about them but they also have a doghouse and the design looks good and you may be able to purchase the plans

Re construction methods, ply is quick. Don't know much about foam but some swear by it. I prefer strip planked cedar but it is expensive and slow. Paulownia is much cheaper and arguably better than cedar. Regardless, the hulls are only about one third of the total cost - the real money goes into the rig,sails, stainless work, winches etc.

Overall, why not buy a ready-made boat - you will save yourself a lot on hassles and probably money too. Someone else will have sorted out the problems


Cheers from OZ

 

Wow I could not disagree more! If you read the pressure specs required for the use of resorcinal glue you will see that to achieve anything like the strength of epoxy, it is way beyond the capacity of the home builder. I have built with it enough to know that it is best left to factory construction where they are able to apply pressures that bring it up to epoxy specs. It ain't going to happen in somebodies garage. Considering that something close to 175 PSI is recommended for it---we are looking at something like 400 tons to glue two pieces the size of a sheet of plywood together if we are to follow the manufacturers guidelines. I can't fathom what the attraction is to the stuff for the home builder. Stay with epoxy.

 

The fact that home builders don't/can't use it to its full potential still doesn't mean that it isn't a stronger glue.

Actually the glue used to make plywood is a bit different. But consider this. If epoxy was the strongest and best glue then why isn't it used to make plywood?

Personally I have only used rescorcinol when I was working for James Wharram.

Richard Woods

 

Thank you Cav and I agree the important thing is the function of a boat.

A boat that you tie up at Monaco so you can be glamorous is very different from a race boat. And neither are necessarily good cruising boats (which I assume is what you want). Many boats are now used for chartering, again the charterer's life style and way they sail is very different to a cruisers.

A cruising boat has to do so many things those others don't have to. They have to be safe to handle both during the day and at night, for example. They come into strange harbours and then need to be easy to manouver and dock. Be quick and easy to raise anchor and hoist sail and so on. And all with a small crew.

While one that can be home built by those with little experience without them spending too much time (ultimately more important than money) is often different again. So it's all a balancing act, or a compromise, or 50 shades of grey.

Fashion is a fickle thing. Skirt lengths go up and down, flared purple bell bottoms are "groovy" one day, then suddenly they aren't "cool" any more.

Same with boats. 15-20 years ago rounded decks were all the rage. Look at the early Fountaine Pajots for example. Trouble was, rounded decks made it very hard to get on board (ask my wife - we sailed an Athena last October) and wasted a lot of space both inside and out.

These days, even for FP, the trend is for flat decks. Also gone are the curvy interiors which might have looked good but were very uncomfortable and impractical. Instead now it's all straight lines - Ikea boats I call them.

However it's easy for anyone to see if a deck is curved or flat. The argument for curved decks was that it reduced windage, so increased speed - true, but maybe only by 1% or so.

What even an expert cannot see without careful study or measurement are things like, for example, what Prismatic Coefficient was used on a hull. Yet choose the wrong one and boat speed and pitching/seakindliness can be affected by 10% or more.

There is more to a boat than its looks. Few of us chose partners based on looks either. We go for their money, their cooking skills and whether they make us laugh.

If you are set on one of those two boats then I know which I'd choose. BTW the Eclipse can be built in foam sandwich, or even using moulds, The Eclipse/Sagitta moulds are free to a good home, contact me if you want them

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

I built some small boats with resorcinal years ago and got to watch how the held up for decades. I never had a glue joint fail. The pressure thing can be a bit deceptive....a panel is normally attaching to things like a chine or stringer where the pressure of the nails isn't spread out so much. The main challenge in this area was keeping up a good temperature as it needed about 70 degrees plus as I recall. Without a doubt epoxy is easier to use and can make up for less than perfect work but resorcinal can have a place for the craftsman.

 

Seriously?...You know better than to ask that question. Many things are used in production manufacturing that are not feasible choices for garage builders. Rescorcinol is one of those. It sticks things together, but outside the lab or the factory, it is hopelessly deficient in producing results that compare to epoxies capabilities in the hands of the typically studious handiman. Rescorcinol was way overrated in its use for the home builder. I would recommend many hardware store glues first. Not because of its ultimate lab specs, but because no home builder is going to come even close to reproducing those specs.