US1metre (question about construction)

Ok this may sound odd (but then it could be cabin fear has set in)

I actually found a site that shows how to build the US1M. Thus generates a question

In the construction of the US1M they plank the hull with balsa strips. Then it is covered with fiber glass cloth.
Now once the fiber galss hass set up is it removed from the balsa wood hull???

Other pictures I have seen of the US1M does not show a wood interior on the hull

Oh the construction site is located at

good for you
to start to build you first boat is a great feeling. i am not sure what you are asking here. but i think you want to leave the balsa in the hull. i assume you planked the hull and used shawdows(temp bulkheads) . so when you lift the hull off your building board. you should have a bare hull. with just your balsa planks and that is it. the fibreglass is not relay strong enough by itself. unless you realy have built up a thick layer.
i have used this method in most of my boats. and i use only one layer of fibreglass, but i leave the balsa in the hull. so that i could glue the servo tray into place. but that is personal prefernce.
good luck and keep us informed

thanks for the quick reply
In the article the fiber glass cloth is coated with expoxy.

And now that I look at the construction sheets it makes sence to leave balsa there to glue stuff to .

On a side note how long did it take you to build the hull (start to finish)?? I am think of doing it as a winter project…but then again


are you sitting down?
it took me 3 hours from stating to glue the shadows unto the board , then planking then fibreglass , then 1 coat of sanding.
it is my black boat . on the my clubs webpage. i used doorskin for the deck. it took me all of 2 weeks to put the hull in the water
glad i could help
and did greg agree with me? sh*t i i am going out to buy a lottery ticket:-)


Holy cow!!! 3 hours
Thank god I was sitting down when I read your post. . Now my interest is really perked up!!!

I think I may read more into this and then look for a really nice but simple design US1M to build.

Thanks again

Jeff -

Down the road you might want to have just a glass hull, in which case, after you lay up the balsa and get it shaped nicely, you can lay up several layers of glass. If you use plastic packaging tape to cover balsa hull BEFORE you add the epoxy/glass cloth (or Kevlar or Carbon) once the fabric cures, the plastic tape will allow you to lift the glass hull up and off the balsa. This balsa could be called a “plug” and obviously multiple fabric hulls could be built from the same hull design. You still will have to finish the outside of the hull, so to avaoid that effort, you would need to make a “female” mold.

A lot of work - and designed for making more than one hull. In the meantime, your balsa hull covered with a layer of epoxy/glass will result in a very nice first effort. Each one you build after will get easier and better looking.

I’m surprised at the 3 hour build noted by Cougar, but not looking for an argument. For first effort, you might want to allow a bit more time!

Just curious-
I can’t imagine planking a hull that quick with tapered and beveled planks? I remember it took me a whole evenings work to do like maybe three pairs of planks on the ones I’ve done.

This makes me think it would be cool to invent a way to make “Cove and bead” strips for the planking just like with a canoe. Hmmmmm.

I’m also thinking of making a US1M by just making a foam plug and covering it with two layers of cloth with resin. scoop out the foam and VOILA!

I do love the look of planks though and it is cheaper.

the way i do mine. is using foam board for the shadows. and the used puch pins to hold the planks into postion. i use glue only in the bow. after planking the hull. that takes about 2 hours. i used resin in between the pins. when the resin is dried. i just pull the pins , and resin the whole hull. then lift. about 3 hours

dick is right about the time
i have alot of planking experinnce so i know some sort cuts. you might want to add a couple of hours to that. my planks are not taperd or beveled. they fit tight. and then taperd in the middle of the hull. i started with a square plank at the deck line. then work plank downwards. untill the planks come under alot of stress. then i add a centerline plank. going from the bow to the transome.the work for theat one out till i meet the planks that started from the deck. only a few planks need to be “sanded” to shape. and that can be fitted into place. quite quickly. all you need to remember is that the balsa planks are there to give the fibreglass some shape. so some small holes are acceptable
good luck

Haven’t had much chance to work further on the <font size=“2”>“COSMIC TERMITE”</font id=“size2”> - but here is another method you can try for home builds.

Basically the stringers are set up to support the hull surface. Then thin veneer is glued up on a diagonal in a “cold-mold” fasion. Once completed, the stringers remain inside the hull, but the hull can be lifted off the building stations which are nothing more than heavy (non-courregated) cardboard. Building board is particle-board. The pink foam is simply used to hold building templates vertical.

Yes, I used two kinds of veneer - Mahogany is the darker reddish color, and the diagonal “accent” strip near the bow is birch. Hull plan is a MISTRAL design US1Meter.

Stringers and first veneer strip: [ Mistral Bow Veneer.jpg]( Lemke/2004227174221_Mistral Bow Veneer.jpg)

More Veneer Added: [ BowVeneer.jpg]( Lemke/2004227173441_BowVeneer.jpg)

View of bottom of hull during application of veneer: [ 3-4bow veneer.jpg]( Lemke/2004227173527_3-4bow veneer.jpg)

Top view of hull before removal of building stations: [ smStarTopView.jpg]( Lemke/2004227173715_smStarTopView.jpg)

THE PLAN: Need to fill all voids along strips. Cover with 1 layer of 1/2 oz. fabric. Decide whether to add canting keel, or build as a US1M ultralight - going with lightweight keel, rudder, fabric deck, and carbon mast, etc.

Some day it will be finished.

it looks good dick.
but why go diagognal? it seem like a hard way to do a hull? . you did a great job with it. did you have to steam the planks?
mistral is a good boat. does anybody know someone who has done advance?

Cougar -
On this one, (first try) I only used a single ply layup. Next time I will do a double ply which add a lot more strength, and the edges between strips don’t have to be so critical.

You want to lay up the veneer on a bit of diagonal, because it bends and conforms to the compound shape of the hull much better. Remember with a rounded hull, you wind up with compound bends, since you are bending a curve (Gunwales to keel curve) and at the same time you are bending the other way for the rocker of the keel. Simply use a piece of paper and you will see that it bends easily in one direction or the other, but not both ways at the same time. Place it on a diagonal, and it bends both ways.

I’m sure Will or Dan can give the engineering reasons “why” - I just know it does. Same with placing glass fabric over the outside of a hull (use existing boat and just lay a 4 inch wide strip of paper over in about the same location as my birch strip) - you will find the cloth will layout and conform to both directions if it is placed on the diagonal so threads (warp and weft) cross the hull at about a 45 degree angle to the keel. If you turn so one set of threads crosses at 90 degrees, you will find it has a tendency to pucker if it isn’t going across a straight line of the keel. Obviously if you lay up 2 layers of veneer, at opposite angles, you begin to get strength like you do from plywood.

Veneer that I used, comes on a roll at Home Depot/Menards/Lowes and has iron-on adhesive on the back. I used an iron to “tack” the veneer to each of the stringers, but then went inside and brushed on a coating of epoxy just to make sure the veneer adheres to the stringers! The roll comes 2 inches wide x 8 feet long, and for the Mistral it took 2 rolls. They were on sale at $2.50/roll when I saw them and bought 8 rolls. Normal price is probably around $4.00/roll.

If you build stringers and set them into the shadow templates, you can strip with balsa in the same manner, and you don’t have to taper any of the strips. Just lay them at an angle to the keel between 45 and 60 degrees. If the balsa edges are straight, you can edge glue. Building this way eliminates the ends of the strips that have to be tapered to fit the curve/bend of the previous strip. Just start up near the bow and hold the strip in place at an angle that you like, and where the strip lays flat. Keep in mind, that after you are done, if you want a “bright” (clear) finish, you have to think ahead in which direction you lay up the strips. I think (personal opinion) I like the strips to start near the gunwale and angle back, down and around to the keel. If doing a double cold-mold, remember to reverse your first layer as the second layer will cover the first!

Because you don’t have to steam or heat the strips to bend them to lay flat against the stringers, it is an easy, non-messy process and building time goes quite fast. Also you can glue with out waiting for strips to dry first if they were wet or steamed. That why it is referred to as “COLD” mold. Many, many plywood outboard runabouts were production built this way during the early to mid 1950’s. If you want to get real fancy, you can special order custom veneer made from exotic wood species.

I have a piece of “bananna wood” veneer that I bought for a deck of a 1 Meter. Didn’t use it all, so have a bunch left that I keep eyeing. It is 12 inches wide x 8 feet long originally, so I can experiment with just how wide of strips I can layup on this little hull. Just think, if you can layup (on the diagonal) a piece of veneer that is 5 inches wide by 6 inches long you have just covered 30 sq. inches of hull surface with a single piece of veneer. Mighty fast build - compared to 1//4 inch wide or smaller strips. Only a layer of fiberglass is faster.

dick how is it for weight? I have always wondered how much a venered hull would weigh.



Now I have to dig it out and take it into work and weight it on the scales and then post the weight (&@&$@^$@^#%$#^$%@!

Anything to keep me busy- right ?

Dan - actually a hell of a good question. Never weighed the thing yet - so will see what she runs on our electronic mail scale at work. Have to go in anyway to enlarge some line drawings, so will take it a long. Will post later.

Hey - weren’t you building a “stripper” some time ago? How did it turn out?


all I can say is WOW I like the looks of the veneer!!!

I take the strips are butt joined, so do you glue the butts? Or is the epoxy coating on the inside good enough.


Forgot to as you or anyone else where can I get the lines for the Mistral or other US1M. looking for full scale. Or how do I tell if the web based lines are correct in printing I did dl the lines for the Magic but cannot tell if the shadow forms are correct in size



Jeff -

the small voids between the strips are of insignificant concern. When overlaying the exterior of the hull with epoxy/glass, all of them should end up filled or sealed. Once the exterior glass has cured, you can always use some epoxy that is thickened with fumed silica or microballoons to add to the inside seams. Using a wide tongue depresser that has been sanded flat on one end, just scrape the epoxy over the seams and the epoxy will fill any voids. The glass on the outside of the hull will prevent and drips or runs, and will prevent the epoxy from squeezing through the void.

Silica added to epoxy will cause the epoxy to become a bit “milky white” depending on consistency. More silica, the whiter the epoxy will get. Exterior epoxy will eventually begin to yellow from UV exposure, so epoxy really needs a barrier coat of UV resistant Spar varnish or Polyurethane with UV inhibitors.

As far as US 1 Meter plans go, again … visit the AMYA US1Meter web site, and click on their construction plans. Scroll down and you will be presented with a listing of five (5) sets of plans for different very competitive boats (thanks to <font color=“green”>Jim Linville, Bob Debow, and Steve Andre</font id=“green”> for making them available for free), and there is also a link to purchase plans for $3.00/set from the Class. A total of 22 different designs are available. Most drawings in PDF format of the cross section templates should print to 100% size on your printer. You can always scale the beam width, etc. and use a photocopier to “tweak” your prints if you find them a couple percent too small.

This link opens an MS Word document that contains links to each of the free plan sets, and also to the AMYA web page for the US 1 Meter Class.

Download Attachment: [ US 1 METER PAGE- AMYA.doc]( lemke/2004228202323_US 1 METER PAGE- AMYA.doc)

<font size=“3”>I can’t begin to say enough about the guys from the class that are willing to share their plans with the rest of us. Truly setting an example that others need to follow to further expand and promote the hobby/sport.</font id=“size3”>

Once again thanks I dl the plans for the Mistral and also the Advance MK1
I think I have the printer set right using form 5 as a reference I measure it out to be 8 1/4 wide for the Mistral and the same for the Advance MK1 (form 6)

And I cannot agree more with your statement of thanks to Jim Linville, Bob Debow, and Steve Andre for access to thier plans. It sure helps a newbie like me.


<blockquote id=“quote”><font size=“1” face=“Verdana, Arial, Helvetica” id=“quote”>quote:<hr height=“1” noshade id=“quote”>Originally posted by dansherman

dick how is it for weight? I have always wondered how much a venered hull would weigh.

<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>

Well - according to the mail scales, it weighs 13.7 oz. (368.5 gr) so while light, it isn’t a featherweight either.

That weight is veneer hull, stringers, cross beams, glass and thicker wood reinforcing where the keel will go. No deck, transom, keel or rudder installed.

Here in the UK we have a Blue Foam, used by house builders for insulation in Walls and Floors.
It does NOT melt when Resin is put on it.
Very light,firm and fine grained it can be carved and sanded very easily.
The RC air-plane folk use it for wings, covered with Balsa or Obechi Veneer.
Cutting is done with a hot bow or a soldering iron, to form cabin cutouts.
Because of its density very little Fibre-glass is needed to finish and make a strong sructure.
I dont know the chemical name of the foam, it is sold as Floor Mate, Wall Mate and Ceiling Mate - -the lightest one.
A Hull could be formed in a very short time, the foam left inside for strength.
I used a similar foam when making the hull for my Schooner, see photos on website.