How to make station molds from an existing canoe?

I have a royalex canoe I really enjoy and would like to build the same model but as a wood strip composite canoe. How would I go about taking the measurements to make the station moulds?

 

Some canoes have the same section/rib shape throughout. They just move them closer to the centerline as they get closer to the fore and aft sections.

 

Interesting question. Setting aside all the new tech scanning stuff, I'd assume the craft was symmetrical so only one fourth of hull would need to be measured. Tape down the keel and at your station spacing for reference (a laser line would be handy). At each station rough cut out an exterior frame (cheap ply or heavy cardboard) to fit in place. Establish final shape either by rolling a pencil in an appropriate size disk around the hull to scribe an offset a circle radius outside the hull or; hotglue a series of narrow strips in place with ends touching the hull.

All this is theory on my part I've no practical experience measuring other peoples hulls.

 

Easiest way is to make a cheap flat mould that goes over (for outside shape)/inside (for inside shape) the hull at the station and then use a joggling stick and record the shape on the mould.

The Joggle Stick – Mastering Skills with the WoodenBoat School https://skills.woodenboat.com/articles/the-joggle-stick/

Edit: I wondered if there was a better article and I came up with these youtube videos.

 

The added advantage of just taking a quarter section, is that you avoid all the inaccuracies the original hull had, as well as any own measuring inaccuracies.
There are some advantages to doing the strip planking into female mould shapes. All the strip surfaces are fair to the outer edge, where strip planking over male moulds shows any strip thickness errors.

Its more difficult to press strips into a female mould though.

 

I roughed out the shape on 1/8" white painted Masonite and used masking tape for tabs. Then scribed that on to another piece of 1/8" white painted Masonite. The white Masonite makes it easier to see to fair as well as the 1/8" is easier to fair with tools.
Then I used the Copenhagen Ship Curves #48 and #41 to fair the Station lines for final shape.
This canoe had all the same shaped stations from front to back. They just moved them in towards the center line as needed.

 

Not sure if the Royalex plans are still proprietary.

If not,

Set the hull upside down on sawhorses and level it. Use a decent laser level and make the canoe and laser even in horizontal and vertical planes. Measure the distance from the centerline of the hull to the laser. Measure at your station increments. 40” to laser from center, then a measurement of 25” in the middle gunwhale would be 40-25 or 15” station dimension. Otherwise, you’ll need a chain jig to takeoff the bows; you could also use a chain jig combined with the laser and map out the stations on builder paper.

 

Very short version: There are no legal restrictions in the US on copying the shape of a hull, provided the shape was not patented less than 20 years ago, or registered under the VDHPA less than 10 years ago. It is extremely unlikely that the shape of Royalex hull shape was patented in the last 20 years, or was registered under the VDHPA less than 10 years ago.

I have previously posted this about various forms of intellectual rights protection in the US.
.
Disclaimer: I am not a lawyer and the information below is not intended as legal advice. The information below are based on research into United States law.

Utility Patent 20 years. Must be applied for and granted. Most boat designs and elements of boat designs don’t qualify for a utility patent because they don’t meet the required conditions. Validity of a patent is only established through litigation. After 20 years the contents of a utility patent are public domain.

Design Patent 14 years. Must be applied for and granted. Protects only the original aspects of the appearance and ornamentation of an object, not it’s functional aspects or construction. Validity of a patent is only established through litigation. After 14 years the contents of a design patent are public domain.

Vessel Hull Design Protection Act 10 years. Registration must be applied for and approved . Designs which are covered by a design patent are not eligible for VHDPA registration. Covers the shape and the hull and deck if they are sufficiently unique. “Protection is afforded only to vessel hull designs embodied in actual vessel hulls that are publicly exhibited, publicly distributed, or offered for sale or sold to the public on or after October 28, 1998.” Application for registration has to be made within two years of the first public showing of the hull. Once the 10 year term expires the design is in the public domain.

Copyright Term varies depending on when the work was created, and for works created before 1978 if and when the copyright was registered. For more information see "Duration of Copyright https://www.copyright.gov/circs/circ15a.pdf Works created after 1977 do not require registration or notice. Terms for works which qualify for copyright are very long. In general copyright applies to “original works of authorship”. Artwork is covered by copyright to the extent it is non-functional. Functional objects are not covered by copyright. Boat plans which are original may be covered by copyright and can’t be reproduced without the permission of the copyright owner (other than within the fair use exemption). However the knowledge in the plans isn’t covered so boats can be built from copyright plans without infringing on the copyright. The "First sale doctrine" allows someone who has purchased a copy of a item subject to copyright to sell that copy of the item, but not to create additional copies of the item for sale.

Trademark Indefinite. “A trademark is a word, phrase, symbol or design, or a combination of words, phrases, symbols or designs, that identifies and distinguishes the source of the goods of one party from those of others.” The name of a boat design such as “Laser” or “Sunfish”, or of a manufacturer such as “Benateau” may be a trademark and if so can only be used by the trademark owner. However, a trademark is not a design so ownership of a trademark does not confer any rights to a particular design.

Trade Dress Indefinite. Trade dress are the unique, visual, generally non-functional elements of a product (or its packaging which is unlikely to apply to a boat) which are identified with its source. Once rights to a trade dress are established they can last indefinitely. Registration is not required though there are advantages to registering a trade dress. I assume that similar to a trademark, trade dress has to be defended or rights to it may be lost. Trade dress appears to have been the primary basis of Hinckley’s claims concerning its “picnic boat” designs. Only certain elements of a boat’s design could constitute trade dress.

License Agreements and Contracts Term depends on the agreement. Private agreements only enforceable by one of the parties which entered into the agreement. An example would be a license agreement between a designer and a builder under which the designer agrees to furnish the builder with plans for a boat and the builder agrees to pay a fee, build only one boat from the plans, and not allow anyone else to build a boat from the plans. Presumably this type of agreement is what is meant by statements such as “buying a set of plans only allows one boat to be built”. A license agreement can also include a requirement that the plans cannot be transferred to another party without their agreement to the license terms. Someone who is not a party to the license agreement or contract cannot be forced to abide by its terms, nor can they require the parties to the agreement to behave in a certain manner. Museums and others who own plans can require agreement to a license agreement which may restrict building of boats to the plans as a condition of purchasing copies of the plans. However owner of plans cannot restrict the building of boats of the designs by parties who did not agree to the license conditions.

David Cockey

Rockport, Maine

7 December 2010

Revised 31 March 2011

Revised 10 September 2018

Revised 28 January 2019

 

I fastened a 1x12 along the middle line of longitude and squared off that for the center line of station molds. All the molds had the same curvature in my case.

Never built, was just curious, went sailing instead and I already have a canoe.

 

Just close enough for me at this point.
Nothing done right until it's done twice on a boat.
Down and dirty spreadsheet below.




When crossing the river in a canoe with a current if one lean into the current face slightly upstream the hull becomes a foil and will have upstream momentum.

 

Hahaha - yeah, sure. Never had THAT happen

 

rwatson,
This is canoeing 101 stuff. So go find someone else to get in a spitting contest with.

 

As I said in other places
"Well, you do the math. 4 knots relative water speed, exaggerated non functional foil shape say 12ft long, 6" chord, non constant power input.
I await you calculations"

Please feel free to link any formal studies you can find, or even conversations from experienced paddlers.

 

rwatson,
4 knots is on the low end of Class II rapids. Water suitable for younger children (ages 4+)
Please feel free to share your calculations. Or are you shifting the burden of proof while cheery picking your data?

 

kenfyoozed,

Here's how the Herreshoff generated Offset Tables And Lines Drawings. You might find some way to adapt their method in a larger scale.