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American Punter
2000 Duckworks Design Contest
Design by Peter H. Vanderwaart
pvanderw@optonline.net

Introduction

A few years ago, my father took a vacation in the Netherlands. At my request, he brought back a couple books about traditional Dutch boats. The most interesting of these is De Punter, by Gait L. Berk. I can't read a word in it, aside from guessing at the cognates, but I have greatly enjoyed the pictures and drawings.

I don't know the exact definition of a punter, but the illustrations show open boats about 20 feet long, with sprit rigs and leeboards. Pictures show them being poled in narrow canals barely wider than the boat, and under oars in wider water. The hull forms are flat-bottomed and double-ended with two chines. The lower side panel is flared like a dory and the upper chine panel is angled in, i.e. shows tumblehome.   The sterns are narrow, as is usual in boats meant to be poled.  There is information about Dutch punters on various web sites, including material by Gait Berk and a site with nice pictures called punterwerf.

Punters are primarily work boats, small barges meant to carry heavy loads. It is picturesque to imagine them piled high with Edams and Goudas, but the books shows more mundane agricultural commodities such as hay. They have an entirely open arrangement with nothing to interfere with loading cargo.

The traditional construction is very heavy. The sawn frames are sided about 2" and molded 3". Planking is from wide boards an inch or more thick. Planking is edge-fastened without longitudinal framing, i.e. no chine logs.

It seemed to me that an Americanized version of the punter would be an interesting entry for the Duckworks Design Contest.  As a shallow water vessel with a substantial carrying capacity, it would be especially suitable for Barnegat Bay, Chesapeake Bay, the Louisiana bayous, and many other places in the eastern United States where the water is thin.

Lines Plan

The size is the largest possible with a bottom made from two sheets of plywood: 15' long and 4' wide. The overall length is about 17'4".

The boat is shaped for optimum sailing performance. The bottom follows contemporary practice: the profile is very straight forward and the widest section is just aft of mid-ships. The ends are blunter than usual, however, to give the largest possible area of bottom for cargo and sleeping. The upper panel is developed from a curve that is widest at station 4 , the attachment point for the leeboard.  A leeboard attached here will be naturally aligned with the centerline of the boat. The intersection of these two panels is a mathematically derived line with an unusual, sinuous shape in profile. It does not figure to be popular with builders. The upper panel ends short of both stem and sternpost, as is true with the Dutch boats; structurally, it is somewhat like a side deck.

The sharply flared lower side panel gives a narrower bottom on a given waterline beam and increased stability as the boat heels. The tumblehome top panel helps the sheer from dipping into the water at a low angle of heel, and keeps standing crew members over the bottom of the boat.

The straight, sharply raking stem is like the Dutch boats. The sternpost shown here is fairly upright by Dutch standards.

For convenience, lines plan was drawn with the ends just at water level. The displacement at this waterline is 1200 lb., enough for the boat, two crew and a couple hundred pounds of gear. With a more usual load, the boat should float a couple of inches higher with the ends out of the water, as shown on the sail plan.

(The shape of the upper sides needs to be reworked before building plans are drawn. The leeboard should be farther forward, and, if possible, the swoop of the upper chine line should be tamed.)

Construction

This is a big boat with a lot of volume, and the construction is meant to be rugged. The construction plan follows American home-build practice with plywood planking and conventional chine logs.

Because the sweep of the sides is flatter amidships and blunter in the ends than a natural sweep, a large number of frames are necessary. In addition, it seemed desirable to minimize the intrusion of plywood web frames in the middle of the boat. The plan shows 10 frames on 20" centers, with 2"x2' floors. The plywood webs are restricted to the sides.

Floorboards with a natural or non-skid finish are dry-screwed (i.e. without glue) to the floors and will play a part in stiffening the hull. Floorboards are a great convenience. They provide good footing, keep gear dry, and provide a satisfying shipiness.

Rig

The spritsail sloop rig is the same as the Dutch original, except the jib is smaller. Most of the rigs pictured are boomless, but not all. With a narrow stern, it may not be possible to get a good lead from the jib sheet without a boom.

(The rig shown here is configured for the leeboard position on the sail plan. With the leeboard moved forward, the area of jib and main could both be increased substantially, to a total sail area of about 125 sq. ft.)

Leeboards

As with the originals, the upper panel is designed to be parallel to the water flow at the leeboard attachment point. The leeboard is hung from a simple pivot bolt through the topsides. The combination of the long board and narrow topside panel creates a powerful lever action at the attachment point, so the pivot point is backed by a reinforced frame.

The same force creates a large bending moment on the leeboard itself. The leeboards are carved from blanks made with two courses of tongue and groove flooring, one course parallel to each edge. The usual Dutch practice is for leeboards to be asymmetric, with the outboard side flat and the inboard side strongly curved. The leeboards pictured in the book have ironwork for reinforcement and ballast.

Rudder

The roughly triangular shape of the rudder is like the Dutch originals, except that they usually have a decorative shape on the trailing edge. The tip of the leading edge is at the same depth as the hull, while the trailing edge is deeper. The pintles are long, so the rudder can rise if the heel scrapes across a shallow spot. A more steeply raked sternpost would make this more reliable.

Poling Platform

A flat fitted high in the stern is a traditional feature. It is a place to stand while poling the boat down a narrow waterway.

Additional Features

Arrangements for rowing are not shown. Just aft of midships, the boat is low and broad enough to be able to use a set of long oars. To emphasize the open arrangement, I have not shown a rowing thwart. The builder can suit himself. The usual place to store oars and quant while under sail is in the bow, one end under the mast partner and the other out ahead of the boat.

Also not shown is flotation. It would be an excellent idea to put flotation between the frame bays, about 200 lb. of buoyancy on each side evenly distributed from bottom to sheer. A soft material like that in the ubiquitous flotation cushions would be comfortable to lean against.

Summary

The American punter is a big, sturdy boat with a lot of capacity. Its best use is perhaps as a cargo craft in support of an expedition requiring the transportation of campers and gear to a remote site across narrow and/or shallow water.

Drawings:

Lines

lines.gif (13322 bytes)

Sections

sections.gif (15695 bytes)

Sail Plan

sailplan.gif (17024 bytes)

line.gif (878 bytes)

 

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