Commentary on Construction by owner/builder Jack Ronda:
<font color=“blue”><font face=“Tahoma”>After a long time in the shop and building stage, I finally got the new tri in the water last Saturday. It was good to see that it floated and the sails look pretty good, if I do have to say so myself.
The boat is called the Pulse and was originally designed by Mike Friend of England in 1998 with an overall length of 48 inches. I bought a reduced size set of plans from Dick Lemke who is the guru of F48 class tris in America and the AMYA.
My Pulse has an overall length of 1 meter so fits in the Mini 40 class, the F-48 Class as well as the MultiONE class.
The technique of construction was what I call the lost foam method. Plywood formers were made for the various cross sections, at fixed equal intervals from bow to transom. Two holes were drilled in each bulkhead for arrow shafts, to go from station 1 through station 9. These alligned the bulkheads in the roll attitude. I then added Styrofoam blocks between the bulkheads, locking the bulkheads in the correct position fore and aft.
Each half of the foam blocks had two grooves to accept the arrow shafts and this locked in the allignment of the bulkheads in roll. Now comes the lost foam part of the technique…you loose a lot of foam carving and sanding the shape of the foam to match the bulkheads.
When everything looks good, you then fiberglass over the foam forms with 3 ounce glass cloth and West Epoxy. Two layers of glass were added. The overlaps were then faired using West Epoxy and micro balloons.
A lot of sanding and fairing later and we are still not done with the glass work.
The beams attaching the Amas (Amas are the outer hulls) to the main hull were fabricated out of the butt ends of fiberglass fishing rod blanks. These were cut to length and then two layers of waxed paper were wrapped around each beam end. A five later wrap of 4 ounce fiberglass cloth was added around that, using West Epoxy to hold things together. This formed the tubes that the beams socket into at the Amas and main hull.
A jig was built (now used for a boat support at the pond) to get all three hulls in the correct position with respect to pitch, yaw, roll, attitude and separation.
The new fiberglass tubes were cut to length and the hulls were relieved to accept the bottom half of the tubes’ cross section. The hulls were inserted into the jig with the beams inserted in the tubes which were located in the proper position, in the hull slots just cut. When satisfied with the fit, the tubes were attached to the hulls using West Epoxy and microballoons. This locked things in accurate locations. The tubes were then capped off to the hulls with an additional later or two of fiberglass cloth, again using West Epoxy. This now locked everything up solid.
The tubes were now glued inside the tubes with West Epoxy while everything was set and located properly in the jig. When done, the three hulls were tied together correctly … forever.
More sanding…and more…and fairing…and sanding, and on and on into the night.
When finally happy with the shape, holes were cut into the hulls for the radio gear and shroud attach points. Covers were made for the openings by laminating fiberglass and epoxy over the top of the hull openings, using balsa wood plugs inserted into the holes and formed to match the hull shape. A piece of Saran Wrap was used as a parting agent before laying on the glass. Five layers of glass were used here. Later, the new hatches were cut to fit and screwed to the hull with sheet metal screws.
Now came the paint.
Several layers of white Krylon primer were applied and sanded …and sanded… and sanded, until it looked just right. (Or until I got tired of sanding.)
Last step was the application of several layers of Red Pepper (Rojo Pimienta) Krylon Fusion paint, straight from the spray can.
The paint scheme was topped off with the boat name “Pimienta Candenta” (red hot pepper) and the boat registration number.
Now this paint business is a pain in the tocas. Before I could paint, I had to construct a paint booth using a multitude of drop cloths from the hardware store, draped over the garage door, door track and a rope suspended between the side tracks. Even with a fully closed box (except for a small gap on one bottom side) paint migrated into the shop, requiring some cleanup of the deposited paint dust. Fortunately, this paint is fast drying, so it dries into a powder before hitting any surfaces, but the intended parts.
I think in the future, I will either have to build a paint booth out of a shed, or wait until the weather warms and I can paint outside.
Lastly came the mast, made from a fishing rod blank, the booms, made from arrow shafts, the rigging and such.
Whew, it was finally done. Oh yes, there were those final details that never end, but the boat was DONE!
Now that the boat was completed, next came the sails.
I used 1.4 mil Mylar and 2.0 mil Mylar for the sails. The lighter material was used for the forward area of the sails and the heavier for the aft edge of the sails. This composite sail gives a soft section forward, where you want good draft, and a harder surface aft, like a full length (top to bottom) batten.
I added battens to the aft section of the sail at all the panel joints and was not satisfied with the way the sails hung when they went on the boat. There was a vertical fold that just seemed to appear on it’s own, when the sail was hung. Joe came over and pointed out that the sail had a lot of roach and on the big tri’s they use full length battens to solve this roach oriented problem.
We added full length battens, keeping the shorter battens previously attached and this solved the fold problem.
Now that we have all the construction features spelled out, I have some photos of the boat and of it sailing in very light air.
The 1 Meter Pulse on her support frame: [ OnStand.jpg](http://www.rcsailing.net/forum1/data/Dick Lemke/2004217172855_OnStand.jpg)
Showing the sheeting and sail servo: [ Gooseneck and Vang.jpg](http://www.rcsailing.net/forum1/data/Dick Lemke/2004217173048_Gooseneck and Vang.jpg)
This shot shows the rudder control, sail servo, and the keel. Note, no keel weight on this boat: [ RearBeam.jpg](http://www.rcsailing.net/forum1/data/Dick Lemke/2004217173319_RearBeam.jpg)
Note the inverted foil on the fin. This attempts to hold the stern down at speed: [ Rudder.jpg](http://www.rcsailing.net/forum1/data/Dick Lemke/200421717341_Rudder.jpg)
On the water at last. Very light air, but it still moves well: [ Stronger.jpg](http://www.rcsailing.net/forum1/data/Dick Lemke/200421717358_Stronger.jpg)
Flying an Ama and heading down the pond: [ Reaching.jpg](http://www.rcsailing.net/forum1/data/Dick Lemke/2004217173550_Reaching.jpg)
<u>How does it sail? </u>
It was hard to tell with the light air, but we found the boat is a dog to turn on a tack in this light air conditions. She goes into irons, before she can get around, and it takes forever to get her out again. On full scale tri’s, they back the jib to get them to turn. Can’t do that without another servo on the mini boats. She accelerates well in the puffs and tracks with just a touch of lee helm. We moved the mast aft one notch and that helped. I got around the tacking problem by just jibing the boat when I wanted to turn around onto the other tack. You really have to plan ahead to make sure you have enough water to make the jibe, without grounding. I did get in two good tacks, when I tacked in a puff, where the boat had good speed. Then there was enough forward velocity to get through the eye of the wind without going into irons.
All in all an interesting experiment. This was the first Pulse Tri built to the 1 meter length.</font id=“Tahoma”></font id=“blue”>
My most sincere thanks to Jack for sharing this information with us. I look forward to warmer weather, and some “stick time” to see how the end result compares with the expectations.