cvdukes
11-11-2009, 02:44 AM
That title should stike terror in many of the experienced folks here but here goes. A quick intro and then I'll like to get a little input on a sail plan for a 12’ skiff:
Back in the Spring, my buddy Rolf and I heard about the National Boat Building competition at the Georgetown (SC) Wooden Boat Show. For those not familiar with the event, the contest provides 3 sheets of okume ply, some cypress boards, tubes of Sikaflex and barely enough nails to knock together a rowboat in four hours or less. At the end of the day, the boats are judged on their workmanship ,and then you and your partner take turns rowing across the river and back in a race while it is filling up with water from all the holes you didn’t get properly caulked.
It sounded like a blast, and so just a few beers later we sent in our entry fee and soon received a set of plans for a Bolger-inspired Monhegen Skiff.
About the end of August, we figured we needed to make some practice boats so we don’t totally stink up the competition. Up until that point, the only messin about with boats that Rolf and I had done together has been loading up an aluminum johnboat with fireworks for the Fourth of July (talk about a Blast:eek:!). His boatbuilding experience consisted of a raft made by strapping car inner tubes to a piece of hardboard when he was about eight years old. My boat building experience isn’t much more: 3 vinyl fabric over wood frame kayaks (2 from kits, one from scratch), and rebuilding a 16’ fiberglass sailing dinghy (but in my defense for this Fourm, I did include lots of wood in it). Since okume and cypress was out of our budget, we made the practice boats out of exterior grade plywood and pine or fir. The first boat took us over a week to build, the second just over 4 hours and a third one about 3 &1/2 hours.
The building contest in Georgetown was great fun. Right before the event, we decided to change some of our cutting and assembly steps (without trying the changes in an actual build:rolleyes:) to make things easier and faster. Actually, our changes ended up costing us at least 20 minutes on the build time and led to several flaws in our boat. On top of that, rowing is not a skill that I possess (as can be readily attested to by any of the thousands of spectators that watched the rowing part of the competition).
Amazingly, we were the second fastest boat that was built (two hours, 43 minutes)…the boat with the fastest build time neglected to use any caulking and barely made it back to the dock. Six or seven teams never completed their boats, including one team that had a nice pile of plywood at the end of the four hours. Somehow, our build time, mediocre workmanship and lousy rowing time combined to move us into second place for the overall competition and we brought home a medal that I could never imagine we would win when we went into this thing. Of course, we intend to go back near year:)
Our deal going into Georgetown was that Rolf would get the competition boat (worth about $600 of marine ply and cypress) and I would get the practice boats to dispose of as I see fit. The plan is that a couple of neighbors will take 2 of them for the cost of materials ($180 +/-), with the stipulation that all four boats have to assemble on the Fourth for rowing races before the big fireworks event. So far, I have cleaned up and painted the first one, and am now working on the second.
I can’t get too excited about finishing these boats as just rowboats (did I mention that Rowing is a skill I’m lacking?). Plus, I get this silly idea about “one day” float tripping down a local river 100 miles or so, then cross 2 large lakes (30 miles +/-) and down a long estuary to the coast. Original thought was to outfit the fiberglass16 footer dinghy for the trip but it’s not ideal for transversing the river section, plus there are a couple of low bridges that would be a pain (even though I altered the mast to pivot on a tabernacle). Hmmm, I could see setting up one of these 12’ skiffs with a folding platform across the seats, adding a boom tent and an easily dropped sail as a one man expedition boat.
My first obstacle in converting the skiff to a sailor was placement of an underwater foil. Given the hard chines and small skeg, I could probably do without much, if anything, sticking down into the water if I want to skimp on sail area, but I know this would be hard sailing in anything approaching a breeze. So it needs a foil.
I suppose I should use a leeboard to save interior cockpit space, but I’ve never been a big fan of them. With this skiff, the widest point comes at the middle seat (2/3 of the distance back from the bow). Any sailplan I’ve drawn with the CE above that point where a leeboard should be just doesn’t feel right…I get a lot of boom over the cockpit area where I would be sitting. I’ve done this before in a small sailboat and it gets cramped after just a little while. Once I eliminate leeboards from consideration, it pretty much leaves me with a daggerboard (not enough room for a pivoting centerboard).
The ideal placement of a daggerboard on this particular skiff would be about halfway between the front and middle seat, except that would interfere with other uses of the boat and the daggerboard trunk would be unsupported laterally. So that left me with the option of either incorporating the trunk into either the aft edge of the forward seat or the forward edge of the middle seat. In the end, I decided to go with the forward placement. The skiff has a butt joint splice under the middle seat and I could envision problems with cutting in the trunk , plus the middle seat location gives rise to the same sail configurations that I rejected with the leeboard idea.
So, I’ve worked a daggerboard trunk into the front seat. I've laminated up some oak for the daggeboard that will have about 1.6 sq. feet of wetted surface area.
In order to balance the sail plan, I plan to step a short mast (approx. 9’) into the forward edge of the forward seat. To bring the CE forward over the dagger, I’m canting the mast forward 12 degrees off of vertical (i.e. reverse rake) to support a gaff-rig mainsail. The gaff will hang nearly vertical, giving the appearance of a Bermuda rig with its peak about 14’ above the waterline. I intend to construct a solid wood forestay that would connect from the stem to the top of the mast. The forestay would be approx. 3/4" diameter oak and would offer some support to the mast (along with standing rigging that may be needed). A 1” diameter pvc pipe would slip over the forstay and form the basis for a very simple roller furler for a small 8 sq. ft jib. The gaff-rigged mainsail would be boomless, but I will include pockets along its luff to hold an extra oar if a boom proves necessary, and there will be at least two rows of reef ties. I calculate the sail would have an effective area of about 38 sq. feet as I am assuming that the luff adjacent to the mast will be basically overshadowed by the mast.
I’ve got pictures of some of this posted on photobucket at http://s658.photobucket.com/albums/uu310/dokoloco/?albumview=slideshow
Pretty unconventional, Huh? The canted mast will probably cut down on gybes and I suspect this rig may a bear to tack. Between the canted mast and the forward daggerboard in combo with the skeg, I may never get this boat to turn! If it doesn’t work, I got two more skiffs to play with.
I know there is a lot expertise on sail rigs in this forum so let me hear your opinions.
Craig
[IMG]http://i658.photobucket.com/albums/uu310/dokoloco/sailplan-1.jpg[/I
Back in the Spring, my buddy Rolf and I heard about the National Boat Building competition at the Georgetown (SC) Wooden Boat Show. For those not familiar with the event, the contest provides 3 sheets of okume ply, some cypress boards, tubes of Sikaflex and barely enough nails to knock together a rowboat in four hours or less. At the end of the day, the boats are judged on their workmanship ,and then you and your partner take turns rowing across the river and back in a race while it is filling up with water from all the holes you didn’t get properly caulked.
It sounded like a blast, and so just a few beers later we sent in our entry fee and soon received a set of plans for a Bolger-inspired Monhegen Skiff.
About the end of August, we figured we needed to make some practice boats so we don’t totally stink up the competition. Up until that point, the only messin about with boats that Rolf and I had done together has been loading up an aluminum johnboat with fireworks for the Fourth of July (talk about a Blast:eek:!). His boatbuilding experience consisted of a raft made by strapping car inner tubes to a piece of hardboard when he was about eight years old. My boat building experience isn’t much more: 3 vinyl fabric over wood frame kayaks (2 from kits, one from scratch), and rebuilding a 16’ fiberglass sailing dinghy (but in my defense for this Fourm, I did include lots of wood in it). Since okume and cypress was out of our budget, we made the practice boats out of exterior grade plywood and pine or fir. The first boat took us over a week to build, the second just over 4 hours and a third one about 3 &1/2 hours.
The building contest in Georgetown was great fun. Right before the event, we decided to change some of our cutting and assembly steps (without trying the changes in an actual build:rolleyes:) to make things easier and faster. Actually, our changes ended up costing us at least 20 minutes on the build time and led to several flaws in our boat. On top of that, rowing is not a skill that I possess (as can be readily attested to by any of the thousands of spectators that watched the rowing part of the competition).
Amazingly, we were the second fastest boat that was built (two hours, 43 minutes)…the boat with the fastest build time neglected to use any caulking and barely made it back to the dock. Six or seven teams never completed their boats, including one team that had a nice pile of plywood at the end of the four hours. Somehow, our build time, mediocre workmanship and lousy rowing time combined to move us into second place for the overall competition and we brought home a medal that I could never imagine we would win when we went into this thing. Of course, we intend to go back near year:)
Our deal going into Georgetown was that Rolf would get the competition boat (worth about $600 of marine ply and cypress) and I would get the practice boats to dispose of as I see fit. The plan is that a couple of neighbors will take 2 of them for the cost of materials ($180 +/-), with the stipulation that all four boats have to assemble on the Fourth for rowing races before the big fireworks event. So far, I have cleaned up and painted the first one, and am now working on the second.
I can’t get too excited about finishing these boats as just rowboats (did I mention that Rowing is a skill I’m lacking?). Plus, I get this silly idea about “one day” float tripping down a local river 100 miles or so, then cross 2 large lakes (30 miles +/-) and down a long estuary to the coast. Original thought was to outfit the fiberglass16 footer dinghy for the trip but it’s not ideal for transversing the river section, plus there are a couple of low bridges that would be a pain (even though I altered the mast to pivot on a tabernacle). Hmmm, I could see setting up one of these 12’ skiffs with a folding platform across the seats, adding a boom tent and an easily dropped sail as a one man expedition boat.
My first obstacle in converting the skiff to a sailor was placement of an underwater foil. Given the hard chines and small skeg, I could probably do without much, if anything, sticking down into the water if I want to skimp on sail area, but I know this would be hard sailing in anything approaching a breeze. So it needs a foil.
I suppose I should use a leeboard to save interior cockpit space, but I’ve never been a big fan of them. With this skiff, the widest point comes at the middle seat (2/3 of the distance back from the bow). Any sailplan I’ve drawn with the CE above that point where a leeboard should be just doesn’t feel right…I get a lot of boom over the cockpit area where I would be sitting. I’ve done this before in a small sailboat and it gets cramped after just a little while. Once I eliminate leeboards from consideration, it pretty much leaves me with a daggerboard (not enough room for a pivoting centerboard).
The ideal placement of a daggerboard on this particular skiff would be about halfway between the front and middle seat, except that would interfere with other uses of the boat and the daggerboard trunk would be unsupported laterally. So that left me with the option of either incorporating the trunk into either the aft edge of the forward seat or the forward edge of the middle seat. In the end, I decided to go with the forward placement. The skiff has a butt joint splice under the middle seat and I could envision problems with cutting in the trunk , plus the middle seat location gives rise to the same sail configurations that I rejected with the leeboard idea.
So, I’ve worked a daggerboard trunk into the front seat. I've laminated up some oak for the daggeboard that will have about 1.6 sq. feet of wetted surface area.
In order to balance the sail plan, I plan to step a short mast (approx. 9’) into the forward edge of the forward seat. To bring the CE forward over the dagger, I’m canting the mast forward 12 degrees off of vertical (i.e. reverse rake) to support a gaff-rig mainsail. The gaff will hang nearly vertical, giving the appearance of a Bermuda rig with its peak about 14’ above the waterline. I intend to construct a solid wood forestay that would connect from the stem to the top of the mast. The forestay would be approx. 3/4" diameter oak and would offer some support to the mast (along with standing rigging that may be needed). A 1” diameter pvc pipe would slip over the forstay and form the basis for a very simple roller furler for a small 8 sq. ft jib. The gaff-rigged mainsail would be boomless, but I will include pockets along its luff to hold an extra oar if a boom proves necessary, and there will be at least two rows of reef ties. I calculate the sail would have an effective area of about 38 sq. feet as I am assuming that the luff adjacent to the mast will be basically overshadowed by the mast.
I’ve got pictures of some of this posted on photobucket at http://s658.photobucket.com/albums/uu310/dokoloco/?albumview=slideshow
Pretty unconventional, Huh? The canted mast will probably cut down on gybes and I suspect this rig may a bear to tack. Between the canted mast and the forward daggerboard in combo with the skeg, I may never get this boat to turn! If it doesn’t work, I got two more skiffs to play with.
I know there is a lot expertise on sail rigs in this forum so let me hear your opinions.
Craig
[IMG]http://i658.photobucket.com/albums/uu310/dokoloco/sailplan-1.jpg[/I