Sabtu, 09 Maret 2013
A Fabulous 15-foot Rowboat
Posted on 19.01 by roronjo
One of the most unique aspects of the St. Lawrence River Skiff (SLRS) is its hull shape which we believe derives from the bark canoes, at least partly. Both hull forms feature a very fine entry and exit to the waterlines. However, on nearly all the St. Lawrence River Skiffs, their after sections are finer than the forward sections.
Many rowboats show the opposite, with the aft sections being fuller. The reasoning behind this SLRS hull form regards how the boat trims when under power (oar power, of course). Once the boat is up to speed, the aft part of the hull settles into the water creating a skeg-type effect. A skeg improves tracking of the hull through the water. But by making the hull itself behave as a skeg, we eliminate the extra wetted surface area (WSA in designer speak) that a skeg creates. Any rower knows one tenet of making a rowboat fast: reduce the wetted surface area! This is one reason the SLRS glides along effortlessly with a single stroke of an oar, creating a feeling of flying.
Here is a shot showing the Fry 15 being stripped up. We built the Fry Skiff in 2013 at WoodenBoat using strip-composite construction. A builder by the name of Fry built these circa 1910 in Clayton, NY. The first shot (left) is the bow. The second (right) is the stern view.
You can see (right) how the strips are fairing into the stern with slight concave curvature even before we've stripped to the designed waterline. The strips are not showing this hollow curvature quite yet in the bow (left). This 15-foot model, shows a pronounced hollow even for a SLRS, partly because the boat is pretty short for a Skiff. (In fact, it is the shortest I'd recommend for fast rowing. I chose the Fry 15-footer because it is going to be the cartopper in my catalog.)
So this is the 'fineness' or 'hollow' in the stern that I am asserting is a classic feature of the SLRS hull form, making the it such a slippery, fast rowboat.
Two other SLRS's that I am working with, the Bobby at 20 1/2' (which was strip-built in 2012) and Clotilde at 18', are true double-enders, meaning they are symmetrical. So one end is not finer than the other, but their waterlines still show a strong hollow fore and aft. Clotilde is unique because its hull is fairly full in the ends compared to the other SLRS, which has me interested because it may be a faster boat and better in a seaway. So I plan to also model this hull and develop mold kits for Clotilde as well. Bobby mold kits are available.
For the first time, the Fry Skiff is newly updated and ready to cut as a mold kit. She strips up perfectly and produces a hull that is fairer than any hand-lofted set of lines could hope to produce, I dare say. The molds receive a roundovered edge so the soft cedar is not dented. A dado is routed into the molds to make a place for squeeze clamps to hold strips in place. The stems are laminated on fore-aft molds. An alignment batten slots all the molds together in place to ensure squareness and proper spacing. The kit is $750 which includes plans package and the molds.
The bow of an 18-footer, Annie. |
Many rowboats show the opposite, with the aft sections being fuller. The reasoning behind this SLRS hull form regards how the boat trims when under power (oar power, of course). Once the boat is up to speed, the aft part of the hull settles into the water creating a skeg-type effect. A skeg improves tracking of the hull through the water. But by making the hull itself behave as a skeg, we eliminate the extra wetted surface area (WSA in designer speak) that a skeg creates. Any rower knows one tenet of making a rowboat fast: reduce the wetted surface area! This is one reason the SLRS glides along effortlessly with a single stroke of an oar, creating a feeling of flying.
Here is a shot showing the Fry 15 being stripped up. We built the Fry Skiff in 2013 at WoodenBoat using strip-composite construction. A builder by the name of Fry built these circa 1910 in Clayton, NY. The first shot (left) is the bow. The second (right) is the stern view.
You can see (right) how the strips are fairing into the stern with slight concave curvature even before we've stripped to the designed waterline. The strips are not showing this hollow curvature quite yet in the bow (left). This 15-foot model, shows a pronounced hollow even for a SLRS, partly because the boat is pretty short for a Skiff. (In fact, it is the shortest I'd recommend for fast rowing. I chose the Fry 15-footer because it is going to be the cartopper in my catalog.)
So this is the 'fineness' or 'hollow' in the stern that I am asserting is a classic feature of the SLRS hull form, making the it such a slippery, fast rowboat.
Two other SLRS's that I am working with, the Bobby at 20 1/2' (which was strip-built in 2012) and Clotilde at 18', are true double-enders, meaning they are symmetrical. So one end is not finer than the other, but their waterlines still show a strong hollow fore and aft. Clotilde is unique because its hull is fairly full in the ends compared to the other SLRS, which has me interested because it may be a faster boat and better in a seaway. So I plan to also model this hull and develop mold kits for Clotilde as well. Bobby mold kits are available.
For the first time, the Fry Skiff is newly updated and ready to cut as a mold kit. She strips up perfectly and produces a hull that is fairer than any hand-lofted set of lines could hope to produce, I dare say. The molds receive a roundovered edge so the soft cedar is not dented. A dado is routed into the molds to make a place for squeeze clamps to hold strips in place. The stems are laminated on fore-aft molds. An alignment batten slots all the molds together in place to ensure squareness and proper spacing. The kit is $750 which includes plans package and the molds.
Jumat, 01 Maret 2013
Update on the Deblois Street Dory
Posted on 19.50 by roronjo
A couple months ago I was entering the final stages of modeling the Deblois St Dory. I am excited to report that the work is complete and a plans package, full size patterns, and CNC cut kits are now ready to deliver!
This boat has been designed unlike any traditional, Swampscott Dory I know of. It has been a few years of hand drawing -- before I entered the world of CAD -- then building a 1/4 scale model, drafting final plans, and the building of hull #1. Then some time passed, sea trials were completed, and my training in CAD went up a few levels! So, then the DSD started getting input into the computer. The latest version of the CAD system Rhino came out -- Rhino 5 -- and I was able to efficiently finish the DSD in this advanced piece of software:
This boat has been designed unlike any traditional, Swampscott Dory I know of. It has been a few years of hand drawing -- before I entered the world of CAD -- then building a 1/4 scale model, drafting final plans, and the building of hull #1. Then some time passed, sea trials were completed, and my training in CAD went up a few levels! So, then the DSD started getting input into the computer. The latest version of the CAD system Rhino came out -- Rhino 5 -- and I was able to efficiently finish the DSD in this advanced piece of software:
One of the great advantages of modeling a boat to such an extent is the ability to work of how everything fits together. All parts of the hull are fit together in 3-D space then the model is taken apart piece by piece and made 2D. These 2D drawings become full size patterns and the kits that are available for my boats. Even for something simple like the tholepins, having them modeled helps see how the sizing of the gunwales and the installation of the tholepins will work out in advance.
I have modeled 8 different sail rigs for the DSD. All parts can be CNC cut or supplied as full size patterns with a package of plans that includes 13 sheets of drawings, a manual, hardware and lumber lists, and direct support from me build the boat. So far two DSD plans sets and patterns have been shipped off.
I love this boat. In an article in Maine Island Trail, I said
"If I could only own one boat � and I hope that never happens -- I would choose a dory for its simplicity and purity of form and function. And when I am daysailing to MITA islands or cruising the trail, the last thing I want is to dread having to row when the wind dies. I want a boat that is as pleasurable to move by oars as it is by sail or motor. And I want it to be a beautiful boat that can be built by a total amateur and used to explore the coast of Maine."
If you want to be at the helm of your own Deblois Street Dory, please contact me. Visit my webpage to learn more and see pricing. Cheers! ---Clint
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