Leeboard Vibration

Have you seen "Principles of Yacht Design" by Lars Larsson & Rolf Eliasson? My wife gave it to me for Christmas.

click to enlarge

Some very interesting stuff regarding the design of keels and rudders, including a table (at right) that may be the source of Chuck's trick of beveling the trailing edge of the foil to prevent vibration. The table compares about a half-dozen different trailing edge conditions.

They also identify three NACA foil sections they consider useful for yacht design. One of which is the familiar NACA 4-digit section my FoilStrip spreadsheet uses (I believe JW specifies foils from the NACA 5-digit series which are identical to the 4-digit series when the camber line is kept flat/symmetrical sections are used. For example NACA 10012 is the same as NACA 0012, NACA 10009 is the same as NACA 0009).

The other two are from the 6-series and have some distinct advantages over the 4-digit section under certain conditions. I may have to revise my spreadsheet to include these.

I wish I had had this book before building my PF's centerboard! Would have been fun to play around with some new ideas!

Tom Hamernik

Lessons in Nautical Evolution

submitted by Steve Lansdowne

Mikesboat underway

Hello Chuck,

Attached photos of the bulkheads framed and roughly layed out with Sean for reference (6ft+)

Getting close to sailing bits for winter... ;) See this link for more photos https://moffitt1.wordpress.com/

We expect to sail her in the Texas200.

Bill Moffitt

Curt-A-Loader Pictures

I finally got some pictures that show what the loader does that I sent in the past.

Curtis Gashlin

Question for John Welsford

John,

Three years ago, I acquired a 14 foot fiberglass rowing/sailing Whitehall type boat, and am having great fun rowing around the San Francisco Bay and Delta area. I am now thinking of building your Light Dory, because:

1. The Whitehall weighs about 200 lb - a lighter rowing only boat would be easier to transport.
2. I would like to build a wooden boat (never done this before)
3. I like your designs, and may someday build a bigger craft
4. The dory looks like it could handle rough water

Summer winds here tend to be 20 - 30 kt, making for challenging rowing. The Whitehall handles some pretty rough conditions but tends to turn away from the wind, which requires attention and effort to keep it from turning broadside to the waves. Do you know how the dory behaves in strong wind? It looks like the stern is a little higher than the bow, which may help it point into the wind.

The Whitehall also has a sliding seat that can be pinned in a fixed position. I have read your column on rowing, so know you are a fan of fixed seat. For me, it is a huge advantage to be able to use the fixed seat for a while, then change to slide seat and use leg muscles to get home. I suspect that a slide seat on the light dory would cause it to porpoise a lot, but do you know if anyone has built a sliding rigger for this boat?

Thanks in advance for the advice,

Rick
_________________

Hi Rick,

Thanks for the enquiry and the implied compliment.  Yes the Light Dory is relatively neutral in cross winds, and if you need to alter then it's easy to carry what in the old days was called a "dory stone".  In this case I'd suggest a 2 1/2 gallon plastic jerry full of  water with 10 ft of light line attaching it to the center seat area.  Going upwind you trim bow down by tossing it up in the bow, and when you want to be tracking well downwind you sling it back into the stern.  While the boat's designed to be neutral so it will track well on all points, you can improve on that for longer stretches of rowing .

That high sheerline astern is to provide the right amount of windage to counter the big skeg underneath. That skeg is there to make it track straight when surfing!

Yes to the rough water, it's designed as a surf dory so will cope with conditions that most rowing boats wont.

Yes to the sliding seat, there are a number of those boats set up with riggers and sliding seats, the extra power is sometimes good to have and it does make for a better exersize regime. .

Yours, John
__________________

John,

I am encouraged to get started and build a great boat. Instead of the Dory, though, I really like the looks and the idea of the Walkabout. What do you think of this as a purely rowing boat? I would like to set it up for one person rowing slide seat, or for 2 people rowing fixed seat. My current boat is the Gig Harbor Whitehall, which has a convertible fixed/sliding seat arrangement I like a lot. Here are some pictures showing the system:

This is the inside of the boat showing the tracks for the seat (the oars have bronze tubes as counterweights - an idea I got from you). People laugh at my tractor seat, but it is really comfortable even after 5 hours of rowing.

View of the rollers

View of the pin arrangement. Pop the pins out to release the slide seat.

It looks like a similar arrangement could be done in the Walkabout. Do you see any problems with this?

The Whitehall is 14.5 feet long by 55 inch beam, weighing about 150 lb. On still water, I can row 3 to 3.5 kts for long distances, and just over 4 kts pulling hard. In a sprint, the GPS jumps around 4.5 to 5.5 kts, but that is the hull speed limit. Do you expect the Walkabout to have similar speed?

Thanks again,

Rick
________________

Hi Rick, that was quick!

Walkabout would be a lovely rowing boat, she was designed as a rowing boat that would sail rather than the other way around and fitting a slider is no problem.  She would be noticeably faster than your Whitehall as she is longer.

Without the sailing rig she could be built somewhat lighter, and that would be a help as well.

I have drawings for a sliding seat designed for the Mollyhawk variation of Seagull, and I am sure that we can put the sheet of plans for that in with the Walkabout plans.

If there are more questions please feel free to ask

All the best for 2008

Yours, John W

Lapstrake Canoe

Here are some pictures of my friend who built this beautiful lapstrake canoe from wood he got when three of us ordered our plywood. He does beautiful work and it didn't take him long to finish it.

Kilburn Adams
www.skiffamerica20.com

Hawbuck EXP

Hey Chuck and Sandra,

How are you guys?  I have been so wrapped around the axle with factory boats and motors that I have not had any time to "play"in months!  I am STILL trying to make that Buffalo River trip.  Could just rent a canoe - but it would be way more fun in a new wooden boat!

This Hawbuck EXP is based on all my "experiences" and freely barrows from many boats with good qualities.  At its heart is a 14" narrow river jon boat - I think you can spot all the other boats in there!  The bottom is 24" which is too tippy for a landlubber like me so I added two more full length panels that angle up 3" - I think they are chines but I call them training wheels!  Anyway the effect will be increase stability until the boat reaches three inch draft - I have no idea how much weight that is - not my thing!

This is number one - the prototype to test the concept.  Also it is the first boat I built upright - interesting technique.  I just blocked up the bottom the shape I wanted and cut each panel to fit that - doubt it is symmetrical and it really is not important to me!  I will take some photos and write some stuff on the launch and testing and if worthy (who am I kidding, this is that most worthy boat I have ever built!) will document building the second one.  It still has a few pounds to go but right now it weighs right at 50 lbs.  This will be the my first boat I do not encase in epoxy - will only do the seams and then paint with off the shelf paint.

Here are some numbers - if anyone wants to draw it up they are welcome - this concept and design should prove very popular!  I would be interested a set of the plans!  Length 14'.  Beam 36".  Bottom 24" curved inward to 14" at the transoms, 4' flat bottom in the middle then 1-1/2" rocker, rising up to 8" (rise starts 24" from transom).  Chines (?) 6" angled up 3" taper to 0 inches at the bow.  Sides are 10" tall and angle in to  24" wide at the gunnels.  Transom is 3/4" plywood with another 3/4" layer with a handle cut out.  Coming will a small deck on each end, canoe style seats, a center thwart, paddle and rod holders.  There will also be three strakes on the bottom for beaching and to give you something to walk on because you will be able to stand in this boat.  Oh, I intend to use a double paddle - will carry a canoe paddle tucked under the side for fishing but primary will be a double.

Larry Pullon

Zen of Boatbuilding

This guy totally understands the zen of boat building.  Every boat is a compromise and always consult your mate on their needs and incorporate these into the build.  Happy boating

Submitted by Paul McLellan

Great Lakes Boat Building School
2008 VISITING BOAT
BUILDER SERIES

We are proud to have David Nichols as our guest instructor for our summer Visiting Boat Builder Series here at the Great Lakes Boat Building School. An experienced teacher, David has been designing and building boats for over fifteen years, and when he isn’t building or designing boats for other people you’ll find him using the boats he’s designed and built for himself. A graduate of the University of Texas at Austin, he has written for a number of boat building magazines like Wooden Boat and Boatbuilder. David has also written and produced several boat building videos and is the author of two books, A Working Guide to Small Boat Sails and Lapstrake Canoes. For more information on David please visit www.arrowheadboats.com.

Click HERE or the image below for a printable brochure with a complete schedule.