Pedal Power or Oar Power - which is more efficient?

You could quantify the efficiency by yourself on an erg to find your power input, and have some one tow you at rowing speed and measure the force speed for power output. Efficiency would equal input/output. You would want to set up the rowing erg resistance so that you would be rowing at the same stroke rate. You could compare the results to you in the same boat with a trolling motor to how much power in watts it requires to go the same speed. I would guess that you are more efficient unless you can get a larger diameter propeller of optimal pitch and rpm.

 

I think your analysis of efficiency of prop vs. oar is right, but it is not pedal vs. oar.
Additionally, there is the detail of the efficiency of the trolling motor that must be considered. How much of the input watts is wasted heat at cruising speed?

 

@SailorDon - I'd suggest you contact Paul Gartside. He's rowed one version or another of his Flashboat thousands of miles, and designed a pedal powered boat that completed a 7,000 mile cruise. Possibly the best source for comparative info on non-racing versions.
Blue Skies trip http://www.wavelengthmagazine.com/1997/on97blueskies.html
The plans http://store.gartsideboats.com/coll...river-cruiser-pedal-boat-blue-skies-design-92

 

I like the design.

It kinda reminds me of Tlingit when looking at the outline of the canopy.

 

Incidentally, why not use a rowing machine mechanism to power a prop?

 

The Blue Skies pedal powered boat is a nice design, but not really suitable for what I consider performance cruising pedaling. It is designed for serious extended long distance cruising pedaling. He mentions that it is desirable to have 300 pounds of cargo because when empty, the design is "quite tippy".
I can achieve the reported 4.6 mph sustained with my Thames Rowing Skiff, so this would not be improved efficiency for me. I would stay with oar designs.

Another big problem is I can't go to the local boat dealer and "test drive" and buy one. It appears to be built from plans, and for someone that has never built a boat (like me) I would have to find a builder, and then what if the boat doesn't meet design performance expectations?

 

A number of boats in the Race to Alaska had pedal drives, some attached to the Hobie fins, some to props. Other boats (like ours, see photo) had oars.

There didn't seem to be any real advantage to any type, everyone moved at about 3 knots - 3.5mph for boats between 20 -38ft (I'm ignoring the small boats and Soggy Beavers). Our two rowers, on a 38ft 5000lb catamaran, overtook a Mirror 16, and rowed for over 6 miles nonstop. See here

https://www.youtube.com/watch?v=_wzBkGRgn50

But I believe the to-fro system is not as kind to the body as the cyclical system for long distances.

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

This is an interesting use of oars. I enjoyed the youTube video.
Thanks for posting.

 

http://fancy.com/things/316097287937853155/English-Channel-Pedal-Boat?list_id=46310712

This English Channel Pedal Boat set a Guinness World Record for the fastest pedal-powered crossing of the English Channel.

Possessing superior nautical qualities that enabled navigation through the Channel’s notoriously inhospitable waters, its ballasted keel provides superior stability in windy conditions for up to three passengers (for a total of 525 lbs.).

Its self-righting, durable rotomolded polyethylene hull cuts through chop for a smooth ride.

Drawing 1' 8" of water, allowing paddling into shallows, it is suitable as a tender for transportation to an offshore boat, or as a way to explore a calm bay or lake.

The boat has a quiet, smooth pedal crank that drives a 16" two-bladed propeller, providing a hull speed of 51/4 mph.

Stopping and reverse are accomplished by pedaling backward. The rudder is controlled by a hand levers located on the right side of the cockpit, providing easy and effective turning.

A protective windshield and high freeboard guard against wind, waves, and water sprays, and the form-fitting recumbent seat is adjustable and fully padded for extra comfort.

Ample storage space is located underneath the rear seat, and bungee cords in the bow hold towels, cameras, or food and beverages.

A transom platform built into the stern allows for easy re-entry after swimming.

It has a built-in manual bilge pump and a collapsible, marine-grade woven acrylic bimini top.

12' 2" L x 4' W x 54 3/4" H. (325 lbs.)

 

If this reply was in support of pedal power, it is a dismal failure.
This crossing took over 7 hours. The solo rowing record across the English Channel is 3 hrs 14 minutes. Less than 1/2 the time of pedal power.

I guess pedal power gets a big thumbs down for efficiency.

 

It was only a 12 foot boat, and 4 feet wide, and heavy. I don't think pedal power was the issue, or at least not the only issue.
I would feel so disconnected in a pedal boat. I think in a boat, especially on a long trip, you need to connect to the wind and water.

 

Here's an old reference with mention of converting rowing motion to prop, plus other interesting info:

http://www.boatdesign.net/forums/boat-design/paddle-vs-pedal-26668.html

Also mentioned: http://www.frontrower.com/bragging-rights.html

PC

 

Thanks for posting this, Porta - I remembered the material and discussion, but I was looking for it in the pedal powered boats thread.

 

I think that is a fine little pedal boat. It's speed is restricted because it has a lot of stability. That doesn't mean it is inefficient, it just means it is slow. Rowers do have a huge advantage in gaining stability with their oars. And if you only care about a boat's motions and stability at cruise, a rowboat can have less static stability than a pedal boat.

 

Main prob w/sliding seats is weight transfer fore and aft in light boat. That is a big part of the reason shells are so long and skinny. Another prob is the pulsing, which is why you might see hydrofoil/planing pedal props or paddle kayaks, but not row boats.

But the sliding seat rowing sure seems good for the body, and it looks real classy.