Dick,
I know you are an experienced builder, how do you control the overall bend when building, the hull is not hogging when you place the veneer sheets ?
Calou
I’ve done a lot of Footy building, and the techniques scale up to RG65’s, too.
1/64 ply is easy to work with because it cuts easily, bends nicely, and doesn’t need to be beveled at the chine joints.
I have found that I can build very straight hulls by carefully cutting out the panel shapes, and then taping all the panels together, applying the tape to the outside surfaces of the hull. Once all the panels are taped, the hull takes its natural shape, though a temporary brace or two accross the shear may be needed. This is the time to get any twist out of the hull. Then apply the glue of your choice to the seams from the inside of the hull.
Bill
As Bill noted, the JIF65 plan is a single chine hull. “Flat” hull bottom and sides *** flat being more or less ***.
There really isn’t much tortured or twisted panel to the design, and what little bending is required doesn’t seem to impart much stress on the framework of the hull. I did a 1 Meter using a cold-mold method about 3 years ago, that that “baby” had a lot of spring-back.
The veneer being used is 1/20th inch thick (0.05") and again as noted by Bill, it bends left/right and up/down at the same time without much strain - although unlike thin ply - this does have a specific long-grain pattern oriented in line with the keel, and catching an exposed edge on sleeve or work bench top corner could easily send a long crack the length of the hull.
I have been careful of this when working on the hull and tonight I hope to cut and attach the last side (port) panel. Then will come some balloon filled fillets along all the seams and stringers which will also add considerably to it’s resistance to twist. Finally, once a deck is added, it takes on a pretty stiff structure. Keep in mind the three internal bulkhead frames made from balsa will remain as part of the internal structure.
I look at some of the designs Bill has in his FOOTY class, and if a panel will bend in 12 inches of hull length - it should bend even easier if spread out over 26 inches in length.
In most cases, tape will be adequate to hold panel in position during glue-up - although I use small clamps when I can to assure tight fit for CA glue “spot glues” (like spot welds). The real key I have found is cutting everything oversize, and then adding about 4-6 hours of careful cutting, sanding and fitting to assure no panel is trying to push another panel out of place. Of course, if I left 1/8" gaps and used filler for the gaps, I would not have the worry or picky fitting concerns. But then I’d have to paint the hull, and this one I am doing my best to keep as a clear finish wherever possible simply to gain the oooh’s and aaah’s whenever possible.
If it also happens to be fast - it will be an added plus. This one is being built as a “Looker” first! :rolleyes:
BUILDER’S UPDATE:
Coming off of a terrible cold this past weekend, when I didn’t even visit the build area, it was nice to get back to the boat, wood, epoxy and dust.
Tonight, I finished gluing on the port hull side and then proceeded to give the hull it’s first interior hull epoxy coating. I had debated on whether to really thin it down as a “wash” - or stay on the thick side. Finally decided to stay “thick” so the internal coat was just a plain coat of “neat” epoxy (no thinner - just the recommended 5:1 resin/hardener mix). The choice seemed to work well, as there was very little “bleed through” of the epoxy. The veneer was thick enough to prevent any major leak-through of the epoxy.
Once I used up my single epoxy mix/batch, I decided to let it cure, and proceeded to take a couple of photos.
Photo 1 i[/i] is a full length view of the hull. At the stern, I ran out of epoxy and was unable to coat the last panel of the bottom. Being uncoated, it is easy to see difference in color and grain. And - yes it will get coated after next epoxy batch mix.
Photo 2 i[/i] is a photo between bulkheads, and it is easy to see how the single coat of epoxy has darkened the red color and brought out the lighter streaks of the grain. It more than meets my expectations of what the final finish would look like. The interior of the hull will only get a single epoxy coat, then be clear coated with varnish or lacquer. Before the varnish, I still must add epoxy/microballoon fillets around all joints, seams, bulkheads and stringers.
Dick
Tomahawk.
in a race with other 20 boats, a little puncture in yor hull skin surface and you pass from a RG 65 to a submarine, in seconds.!!!
RG 65 are competitive as well as you keep them with minimum weight. If you want one for enjoy its appeareance or the simple joy of sail, any material is fine. If you want to race…“think light all the time”, light hull, light sails, mast and booms and light servos and batteries too.
Many people build boats as a hobby or with no intentions of race, but once they got involved with that they find out the boat is not a ood performe because of the weight and think the design sucks…but many times is the skeeper finger or boat weight. In 2008 some jif 2 was at the top list in the argentinian sudamerican chamopionship, way better than many carbon fiber stuff…just because of weight!
Hope to be useful.
Tato Lazo
Tato Lazo
After taking the weekend off to B.S. with old multihull friends back in Michigan, today I sanded down and applied the first coat of epoxy to the exterior of the hull - both the bottom and the sides.
For some who are woodworkers, I decided to drop these photos into the thread - more for an “interest stirring” reason. At the same time, the coach house and deck are starting to be worked on. Once they are completed, I think the boat will be a terrific “draw” for the public as a static model, and also a bit of “eye candy” when on the water.
Photo #1 - view from the stern, a nice coat of epoxy brings out the hidden grain in the veneer.
Photo #2 - view from forward and port side showing the planned grain pattern designed to “run over the chine from bottom to side”
Photo #3 - a closer view of the veneer grain on the hull bottom