Stretch Limo US One Metre

Hi all, Was wondering if anyone out there has stretched out a us one metre boat to suit a marble head rig and how successful was it. I am curantly in the process of doing just this although I think i went a bit big for M rules by making the boat 1.5 metres long. All I have done is make the shadow spacing 150mm and not changed anything else at all. Will let you know how it turns out when it finally gets in the water.
Cheers From down under

This could be good or bad depending on what design you are working from. However, it will most likely NOT be optimal as an M. Which design are you “stretching?” There is a chance I could throw it into the computer really quick, stretch it, and feed you back some important numbers (such as displacement etc).


I went the other way - using an older M class set of cross sections for my first 36/600.

I did have to add a bit more freeboard, but it sailed fine, and was a good building/learning experience.

The design I am stretching is called the Orco 2 by Swede Johnson. It is just a set of shadows that I downloaded ant thought looked good in my inexperienced opinion. What would be the keel length and ballast weight. I am probably going to use one of my old Heli blades as a keel which will give it a lenght of about 450 - 500mm once installed in the hull.
Thanks for any input as i really am a beginner.

Well the stretched Orco 2 is well under way with about half of the planking done. I almost wish I had built more planes when I was flying. Truth is if I had built anything other than ARF (90% Built when bought) I might have had some idea of what i was getting myself into lol. Anyway this is certainly a great experience for me and one I am sure to repeat in the future. As I said I will keep you all updated on the progress of my first scratch buitl boat and welcome any comment’s/suggestions.
Here is the latest pic.

Download Attachment: boat1.JPG

A suggestion: Might want to eliminate that large metal structure from the hull, as it’s drag and size will greatly reduce performance ! [:-boggled]

Actually, and in seriousness, it looks like you are well on your way toward a really nice build. I am assuming your bow is down with stern up in the photo? If so, are you sure about the rocker line of the keel? It “LOOKS” rather a bit forward - well in front of where I would suspect the keel to be. Most designs (???) seem to have the keel rocker (deepest point) just forward of - or almost at the location of the keel, allowing for the hull to spin at that point in conjunction with the keel when tacking/turning.

I am not familiar with the Orco design - and all I am saying it “seems” strange - perhaps not. From the photo, it seems the keel takes a pronounced drop from the bow (stem) to station # 1 and then remains pretty flat through stations 3 and 4 - at which time it begins the gradual upsweep toward the stern. Definitely the displacement and buoyancy is well forward, and this may be helpful downwind - or when the jib is “pressed” upwind in gusts. Will be very interesting to see how the hull performs. Do you generally have light winds in your part of the country?

One way to figure out the ballast might be to cover the balsa hull with saran wrap (or glassed balsa hull)and put the hull in a pool. Bag-o-saran wrap as it were to keep hull dry. Suspend 7 or 8 lbs of lead under the hull in the fore/aft position of the bulb. Tape a rudder “shape” and a fin under it too in their normal positions but sideways. Fill the hull with weight until the boat floats on its lines. Weigh the stuff. That should be pretty close to the total weight of the finished boat.

Bulb plus servos, etc = weight of stuff + weight of suspended lead.

I think this is easier to do than to describe.


Funny how things go in a circle.

Swede Johnson, designer of the Orco series of US One Meters, is a California based sailor and model boat designer still active in racing and building. (Lately he has been spending time on schooners.)

The Orco was a development from Swede’s original “Skinny” series of Marbleheads. Essentially, then, what is being done here is a kind of “Message to Garcia”-- a marblehead derived One Meter is being copied back into a marblehead.

Unfortunately, simply lengthing (or shortening) a hull, doesn’t usually produce a successful boat. Basically, you need to “expand” the boat over all its dimensions to maintain the original design concept. And even then, a design that works in one class often won’t work in another.

This exercise also raises some interesting questions of the use of someone else’s work without persmission. This isn’t the situation of building an exact copy without consent, but to me it alsways seems the best thing to do is to ask the designer first.

Final suggestion, try to contact Swede and show him your boat. He might be able to help you with the keel placement and balance and give you some insights into his work.


The boat looks nice! As I recall from the online plans at, the Orco 2 is a bit of a strange bird, but it looks good.

Roy, I was under the impression that since the plans were on the website and free for download, that they were free materials that could be stretched and altered at will. Is this not the case?

Just curious


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

Definitely the displacement and buoyancy is well forward, and this may be helpful downwind - or when the jib is “pressed” upwind in gusts. Will be very interesting to see how the hull performs. Do you generally have light winds in your part of the country?
! [:-boggled]

<hr height=“1” noshade id=“quote”></blockquote id=“quote”></font id=“quote”>
Dick, the aparrant forward displacement/boyancy is the main reasom I chose this design over the other free plans available as we generally have hevier winds here and after watching the IOM boats (thats all that sails in my club at the moment) the main problem with them seems to be nose diving. Thanks for the input, seems I may have gotten something right at least with my choice of design ha ha.

Well 8 hours of planking sees the end of the balsa stripper and the start of the sanding block. Finally I have something that almost looks like a boat[:D]

Download Attachment: 8hours7.JPG

Download Attachment: 8hours6.JPG


how wide are those planks? looks like 1/8" to me, but maybe its the photo, or the fact that i have had 3 hours of sleep in the last 40.


no, the planks are about 3/8" with a total of 41 planks including keel plank and a total of 28 tubes of super glue lol

well 2 hours with the sanding block sees a balsa plug ready for a bit of flow coat so as i can get a mould. It also brings about the time when i need to ask a few questions of the more experianced builders out there, mainly what would be the best weight/type (ie chopstrand or woven) of fibreglass matting to use for an all fiberglass hull. It seems a shame to not use any of the balsa in the final boat but that is the way i decided to go from the beginning (don’t know if this is the way to got or not but then again this whole project is a bit that way ha ha). also will it need any sort of bulkhead/re-inforcement in any particular areas eg: keel,rudder area? Once again thanks for any help/suggestions.

If you are only building one boat there is no reason not to use the “plug” as the hull. Just put on a lay of glass cloth(1 to 4 oz),sand it smooth and you’re on the way. There are lots of balsa boats out there. You will need re-inforcement around the keel trunk and a block for the rudder. Give the interior a coat of resin to waterproof it. With a “made up” design like this, using the balsa hull is probably the way to go. You can finish the boat a lot easier and get it on the water to see how it does. If it sails well then you can use the hull as a plug to make a mold. If it is a slug you can put it on your mantle and try again.

Don Case
 Vancouver Island

P.S. If you havn’t done it already, go to the AMYA site and download the US1M Construction Guide. It covers most everything.

Thanks for the input don but unfornunatley because i decided not to use the balsa from the beginning (and also because of inexperiance) i have permanatley glued the balsa to the shadows and the shadows to the building board so now I have no choice but to only use it as a plug. The US1M construction guide you speak of seams to only talk about building a boat using balsa as part of the boat(or maby I just read it wrong, will read again to make sure) hence my question as to what size/type glass matting for a glass only boat.Also how many layer’s of fibreglass will I need for both a 1.6 metre boat and a 1 metre boat that I am also building?

My guess is that no more than a double layer of 4oz. glass is necessary if there is no core. Even that might be a bit over-kill - because you can always add glass (or carbon) in areas needing strength. (Keel, rudder, and near chainplate attachments).

I think discussion elsewhere kind of pointed the same way - use the cloth to keep the water out and only add extra everywhere stress or strength is happening/needed. As you curve the glass into compound shapes/curves, you add inherent strength because of the curves. (The old egg, viaduct, VW Beetle shape examples from Physics class 101)[:D]

I found to above link to the IOM compendium page incredibly helpful when it came to selecting a lay up schedule.

Check it out.


sorry to all those that were waiting to see how the Limo turned out but the project has taken a turn for the worse with the plug being destroyed due to a combination of my bad temper and certain Gladstone Model Yacht Club member attitudes (one persone in particular) all my radio gear is now for sale and i will no longer be persuing this hobbie. Thank you to all that have helped through out this project and again sorry there won’t be any results of boat performance to talk about.
Good bye from Qld_Panther

Live Hard, Die Young and Leave a Good Looking Corpse



_/ if it isn’t broken, don’t fix it! _