Hey folks, I'm a new to the forum and a novitiate to boatbuilding (on just my second boat). I'm currently drawing plans for a 15 - 16 foot sailing pirogue. Question: is there any standing equation/formula/incantation for determining and plotting rocker?
Determining rocker
- Thread starter doc
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Welcome aboard.
JEM is the designer here and he should be able to help with that question :!:
I am currently building a 50/50 Sailing kayak, the bow is 2 3/8" and the stern is 1 11/16"
JEM is the designer here and he should be able to help with that question :!:
I am currently building a 50/50 Sailing kayak, the bow is 2 3/8" and the stern is 1 11/16"
I like drawing up canoes and kayaks and I fit in with the nuts here. But I'm not the designated or exclusive designer here. Chuck welcomes all nutbags. :lol:
I don't know a whole lot about sailing but have a good friend that is a retired naval architect for the Dutch navy. I'll ask him if there is a generallly accepted amount of rocker for sailing.
I'm assuming the pirogue won't be wider than 36". So that's a lot like a sailing canoe. In which case, 2-3" of rocker on each end is pretty common for a canoe specifically designed for sailing.
I don't know a whole lot about sailing but have a good friend that is a retired naval architect for the Dutch navy. I'll ask him if there is a generallly accepted amount of rocker for sailing.
I'm assuming the pirogue won't be wider than 36". So that's a lot like a sailing canoe. In which case, 2-3" of rocker on each end is pretty common for a canoe specifically designed for sailing.
Thanks fellas, I appreciate any help I can get. I've been paddling canoes and sailing skiffs for a long time. And then, I built an 8' pirogue as a toy box for our first grandbaby. Don't you know my son (bassfisherman who likes to fish beaver sloughs and "lost" farm ponds) took it fishing... and the little boat worked...packed in easy (lighter than his deer climber stand)...and scooted across the lily pads with barely a ripple (according to him). So I built a 12-footer for myself...I'm hooked. Now I want to combine paddling and sailing. Any words of wisdom are much appreciated.
If it's going to a combination of both, I'd say keep the rocker closer to 1" or 1.5" on each end. If you paddle a lot in waters with tight twists and turns, then maybe 1.75" on the front. Those would be my personal preferences.
Flat bottom boats for paddling tend not to want to track straight if you have generous rocker.
Flat bottom boats for paddling tend not to want to track straight if you have generous rocker.
Matt has more experience here than anyone else on designing great boats,the rest of us are just builder,so his advice carries a lot of weight with me.
One other way I would research is looking at existing plans on the net and the configurations of the hull.
Good luck
Ron
One other way I would research is looking at existing plans on the net and the configurations of the hull.
Good luck
Ron
Thanks fellas. Now I gotta go rip out a tool cabinet I built into my work shed so I'll have room to get a 15-footer out when it's finished.
Okay...got it rough sketched. Going with 1.5"-bow and 1.0"-stern on Matt's counsel and Ron's endorsement. Y'all have never steered me wrong before. And regarding the extension on the work shed...already extended it once and the boss and the neighbor didn't like it. Seems the boss doesn't understand the essential nature of a fridge in the shop and the neighbor hasn't learned how to appreciate not having to mow 24 sq. ft. of his lawn anymore.
Drawn her sides-as-cut at 15'6". I figure that should give her LOA of about 15'. Drawn beam at 32". Instead of stems on the last boat I stitched her loosely and ran a 3/4 dowel through the cable ties on the inside of bow/stern after laying in thick fillet. Then drew cable ties tight and capped outside with with same fillet. When cap-fillet began to kick I covered it with wood flour and rounded it with my fingers. After curing I faired it with sides and smoothed out the rounded exterior seams. Added cosmetic fillet on interior seams. Turned out great. Thinking of doing same thing with sailing pirogue only using 1" dowel (due to haunting memory of jughead running his aluminum fishing boat into my bullseye-style sailing skiff).
About four years ago, friend Keith and I were involved in patching up a 100 year old stripper pirogue. It was built on the north shore of Lake Ponchartrain with 3/4" X 3/4" strips, edge nailed with square nails - way before epoxy and glass. Anyway it had this funny little seat in the front with a hole in it that wasn't wide enough for anything but a small child's behind.
some folks that saw it opined that it was for a small mast, so it could well be a sailing pirogue
it was long and lean and had very little rocker
Of course it was a work boat and it's unlikely that the original owner used it for Sunday afternoon racing at the yatch club
some folks that saw it opined that it was for a small mast, so it could well be a sailing pirogue
it was long and lean and had very little rocker
Of course it was a work boat and it's unlikely that the original owner used it for Sunday afternoon racing at the yatch club
Crossing Lake Pontchratrain would be easier with a sail, though - wouldn't it? Was there evidence of a mast step beneath the hole?
No mast step when we got it, but It could have been removed, rotted out , or whatever. You don't need muchofa mast step for a 1 1/2" mast anyway. Probably a pretty small sail, the guy was likely only trying to get a little relief from paddling