A Sailing Cargo Ferry

03 June 2018     Editor    5 Comments.

Harryproa has an interesting cargo proa concept: an inter-island ferry/cargo vessel for East Timor. The brief calls for 10 tons of cargo and capacity for 25 passengers, primarily (but not only) wind propelled, a crew of 2, shallow draft and beach-able, built and repaired by local semi/unskilled labor with minimal equipment and easily obtained materials, and a large tender.

Naturally, Harryproa has determined that a harryproa is the best platform with which to achieve the above goals.

The loads on the structure do not alter appreciably regardless of whether the long hull is loaded or not. The boat will sail faster when empty, but the loads on the beams and rig are unchanged, saving structural weight.

A point I agree with, see The Case for the Cargo Proa. The solutions presented here are creative and thought-provoking, what do you think?

Harryproa: Sailing Cargo Ferry

Much thanks to Paul C. for the submission.

 

 proas / new designs 

5 Comments

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11 Jun - 17:07

rob denney

Micheal, Thanks for publishing it. Since we drew it, the response has been huge, there is definitely a big demand for this type of transport all over the Pacific. We have made some serious weight and cost savings as we went down the design spiral and some big improvements on cargo handling after talking to the end users. Next steps are survey approval and operating logistics with the short term goal of a setting up a harryproa shipping company. regards, Rob Denney http://www.harryproa.com

14 Jun - 17:12

Halsted Morris

Why have the "outrigger" so short (LOA) if you want to carry so much cargo?

08 Jul - 10:50

Joel

These articles answer a lot of questions I had about cargo hauling on a multihull. Curious about long distance hauling of only cargo, anticipated speeds upwind, downwind, reaching and size / drive type for the auxiliary.

08 Jul - 17:09

rob denney

Halstead, The cargo is carried on the long hull. Making the short hull longer adds weight, cost, windage, torque to the beams and corkscrewing to the motion upwind. Joel, For long distance freight, the crew will need accommodation, but otherwise, there is not much that would change. Anticipated speed upwind with a full load will be good, but not spectacular. It should tack through 90 degrees, with ~10 knots boat speed, in flat water, less in waves. Route selection and weather routing will be important, as will optimising the load weight for the route. Downwind, it will be a trade off between vmg sailing and ddw, depending on the weight of the cargo. Reaching, it should do wind speed or better between 5 and 20 knots, the same as the cruising harrys. Empty, it should perform as well as any of the big racing multis. The auxillary is mounted on the tender. It will be either a diesel outboard with a big slow revving prop, which, fully loaded should push it at 8 knots in flat water. Or, solar powered electric drive, which, on a sunny day should make 6 knots. Depending on the route, there is a decision to be made about batteries, gen set or only pv panels.

09 Jul - 13:41

Joel

Thank you, good luck, & congratulations!