Fiberglass-less hulls and bigger sails?

I’ve taken hull plans for a WRC21 from the WATER RESIST site and scaled it down to 1m to serve as the basis of a catamaran winter project. I don’t plan on racing this one, just keeping myself busy and learning the some of the skills of building. In the summer I enjoy camping near a pond on Cape Cod and thought it would be fun to bring a boat down to play around with.

Given that I don’t need to conform to class rules, there were two modifications to building that I would love some feedback on:

  1. Instead of covering the extruded polystyrene hulls with fiberglass, how about just a thin coat of resin? This would keep it from getting dirty or dinged and give it a little structural integrity, without the hassle of setting up a fiberglass-laying operation in our living room. Alternatively, I could lay up a thin strip of glass in the middle to attach the platform and maybe a bit in the front and back for additional protection.

  2. A jib also seems like more work than it’s worth if I don’t plan on racing. With sail area restrictions, I’m sure that it’s neccessary to get the most bang for your buck (or bang for your square inch). For a recreational boat, though, what about just putting on a bigger mainsail?

Thanks for any advice. This forum has been great help so far in providing ideas and suggestions.

To waive the fibreglass is a bad idea. You loose a lot (90%) of the stability but just loose minimal weight. [:(]
Resin doesn’t protect your boat from getting dents and doesn’t add to structural stability. Even the thinnest layer of glass does both.[:-slaphappy]

It doesn’t make a big difference if you paint your hull with resin or add some glass to it. You need to wear the same protection and have the same mess in your living room. [:-shake]

I don’t like jibs either. I like it plain and simple, but im my experience jibs help a bit to get the cat through the tack. If you just use the mainsail you risk to get slower in your turns.
If you decide to use just the mainsail anyway, you have to take care that the CoE of your total sail area stays about at the same location the designer had planned it with the jib on…

just my two Euro-Cent,


Sounds like fun :). I agree with the ‘leave the fiberglass on’ sentiment, too. It adds a lot to the protection aspect. You don’t, however, have to use resin, though. Model plane guys use CA glue (cyano-stuff) and/or epoxy. If you try CA, check it on your hull material first! Foam has a nasty habit of dissolving! I found out the hard way with spraypaint on a wing sigh. And if you’ve never worked with it, be sure you’re not allergic (like me (another sigh)). The ‘odorrless’ CA’s essentially eliminate the allergy and foam-dissolving properties. Epoxy is kind-of odorless, too…

Hmmm - no jib. No jib. Why not? I used to sail an AquaCat. FOr those not in the know, it was a 12’ cat, not quite as fasst as a Hobie (but a lot cheaper) with a unique rig. The mast stepped on the forwardmost cross brace with 2 solid ‘stays’ forming an A-frame from the trampoline up to a point halfway up the mast. It also had a large foam ball at the mast-head which prevented the boat from turning turtle if you capsized it during over-exuberant 14-year-old-boy sailing (I’m here to tell ya). That ball isn’t a bad idea, either (strong hint).

There is nothing - absolutely nothing - half so much worth doing as simply messing about in boats. Kenneth Graeme, Wind in the Willows.

At 1 Meter in length, you qualify for both the MultiONE Class <u>AND</u> the F-48 Class. (MultiONE dependant on sail area) - so never can tell if the desire to race should strike - you could ![:D]

Mainsail only - with your trimaran configuration, you won’t have as many issues tacking as with a cat, but still it will be different. As noted, dropping the jib, will provide a shift backward of your Center of Effort. As it moves back, you will begin to experience weatherhelm. A little bit is good, more is OK but too much is a problem, as it will require rudder action to keep from heading up into “irons”. You may need to move your mast forward to compensate for loss of jib sail area - this will help balance the boat.

A uni-rig will work, and probably will be faster upwind, and point higher than a jib and main. Interestingly, many monohull classes don’t permit a uni-rig - so one must wonder how come? (rehtorical question only) Maybe they are. Where you will miss your jib is a)… tacking, and b) sailing off wind and on reaches. Also, if you go with maximum allowable sail area - a mainsail only will require a much taller mast to carry same sail area as a jib/main combination. This creates additional stability issues (tipping & pitchpole).

Finally - as most have already suggested - foam even with a single glass layer is still able to be dented. If you are going to spend the hours required to shape the boat, build the rig, build your sails, cross beams and floats - please don’t cut yourself short by avoiding at least a layer of 2 oz. cloth to prevent the nicks and dents inherent with sailing (and carrying) a boat this size. Just a reminder - a MultiONE CANNOT go through a doorway without holding boat sideways !! And if it is rigged, even more problems - especially if trying to go through an inside door and a screen door. Add in auto closing door mechanisms, and you will soon see the problem. Add in the 66 inch (approximate) mast, and you will be banging into the door frames, hanging lights, etc. This is NOT an IOM that is easy to get through a door by tipping downward and leading with mast tip - so please add glass protection.

This is a one meter in the pickup bed of a standard 1/2 ton (Dodge 1500) truck ! They are big even when they are small !!


Just a sideline(off topic doh) how do you find the control on your MultiOne with the headsail seeming carrying the same (obviously slightly smaller) sail area as the main.

Cat’s can be alot of fun to sail as a R/C boat. I used to race one quite successfully. Suggestion would be though to keep your sail area down to around 75% of the maximum size to reduce most of your pitchpoling and capsizing problems.

Seeing as it is being built for a recreation “toy” on holiday’s you don’t need the hassle of having to concentrate to hard on sailing the boat to keep from swimming.

I agree with everyone else. If you are going to go to the trouble of resining your hull’s you might as well add a layer of cloth. The extra stiffness that it will provide as well as the protection factor will be well worth it.


Peter - Hi … hope the racing season is going well for you !

A couple of things…

  1. There was an initial tendency to have a bit (too much) lee helm on first sail. Although it was designed for 13 degree of rake, when first installed it was overlooked so mast was nearly vertical. Once I raked the mast back, my CofE moved back over the board and I wound up with neutral helm. I think I may need to move entire mast back, as I prefer weather helm to neutral. It lets the boat “hunt” for wind shifts and lifts.

  2. I think my next sail iteration will be to shorten up the jib, bringing it down in size relative to current dimensions. Just seems too big when looking at it - but then I am pressing the 1100 sq in. (.89 sq mtr) sail area limit, and had to put the extra sail area someplace. Obviously this is very light wind sail. I also found on first sail the fat head had too much twist so I installed a “twist limiter” at mast head that can be adjusted for amount of twist desired. (on land - not on water). This made me think about a pin-head main.

  3. As I work on my landyacht mast, I am having ideas on battens for this one, but I need a mast with some trailing edge to capture and hold leading batten edge during a tack.

  4. Finally - I had the MultiONE out only twice before my stroke in late August - so sailing season was past by the time my feelings started to return - so a lot of testing will happen this spring. Feelings in hand/foot are slowly returning. <font color=“blue”><font size=“1”>[Want to take time here to express my thanks to those who sent well wishes during early recuperation. Received and greatly appreciated. Helped a lot in the healing process and reminded me why I want to get better and get back to building and sailing. Thanks again]</font id=“size1”></font id=“blue”>

BTW - I am moving back to the work on the F-48 and hope to start doing the radio work soon on it. While the original foam was glass covered, I have decided to use them as plugs for a set of “hollow hulls” strictly becasue of weight. Winter is just about to set in - calling for -30 degree temps this weekend, so basement family room will begin it’s conversion to workshop again.