I can’t believe that after more than 3 years of planning this project, I depart for Hawaii in a little more than 4 months from now!! One of my goals during the recent Vancouver Island inside passage sea trials was to learn more about how my human powered boat WiTHiN handles various wind and sea conditions so I can start planning a route from Tofino, BC to Hawaii. As you know, for safety reasons, I am doing the crossing with a safety boat piloted by my good friend Clive McGowan. Clive and I have been discussing various route options and here are our latest ideas.
PedalTheOcea.com safety boat "Theodora". Skipper: Clive McGowan
It may seem like the fastest way to get to Hawaii from Vancouver Island is how an airliner would fly it – a straight line (or also called a “great circle route”). As the bird flies, 2458 nautical miles is the shortest distance, but this route does not take best advantage of prevailing winds and currents. There is a sail boat race every year from Victoria, BC to Maui and the route they take is south from Victoria, along the coast to California, then west with the tradewinds to Hawaii. This route is 2504 nautical miles, but obviously, the sailing yachts need the wind.
To compare these two options, I ran some simulations using a computer application from PedalTheOcean.com sponsor Visual Passage Planner. VPP uses pilot chart data for every month of the year to calculate average wind speed and current direction, wave height, and % chance of gails for any point on any of the oceans.
I spent some time developing a speed profile for WiTHiN using estimated assistance from wind from what I observed during the inside passage sea trials. The VPP program is pretty powerful in that it will consider the speed of my boat in various wind angles, wind speeds, and currents – all from a specific month, then optimize a route based on a custom weighted speed vs wave height specification.
There was a time on the Johnstone Strait where I was drifting and I was measuring 1 to 1.5 knots of speed in the right direction. I told you before that I didn’t know if it was from current, or wind, but I realized today that I could find out using tide tables for the area, and time data from the Spidertracks map showing our track: http://adventuresofgreg.com/blog/about-2/
Vancouver Island inside passage sea trials route
To see if my speed was from tidal currents, I looked at the area where we got held back due to the tide current and figured out that it would have been about 4:00 pm. Then I looked at the time later on that night when I drifted at 1 to 1.5 knots. I wanted to see how much of that would have been due to current, and how much due to wind. It happened at 2:00 am, so a current would have been running AGAINST me. I looked at some current numbers for this area and they aren’t a lot anyhow – but for sure, my 1.5 knots was not due to current. It would have been due to wind. The forecast for the night was 15 to 20 knot winds from the SE.
We were caught in the currents at 4:00 pm
I drifted at 1.5 knots at 2:00 am
When creating my power profile in VPP, I used the “power boat” setting, and I decided to be conservative and use 3 knots average speed over 14 hours per day. I had to enter an overall cruising speed (from power – not wind or current) of 1.75 knots because there is no way in the program to indicate that I can go 3 knots for 14 hours per day. It assumes I am in a power boat and will run the engine 24 hours per day. So, I figured that 3 knots for 14 hours is exactly the same as 1.75 knots for 24 hours.
Then I created 3 possible routes: a route that was a straight line / great circle from Tofino to Hawaii, a route that was fully optimized from Tofino to Hawaii and a route that got me far away from the coast immediately with a perpendicular line (to get away from the dangers of land, and out of the shipping channel), then optimized the rest of the way to Hawaii. Here are the results:
Great circle route
Great circle direct route:
estimate trip duration: 46.8 days
ave boat speed: 2.2 knots
average wind: 12.7 knots
average current drift: .4 knots
average wave height: 4.3 ft
Optimized route
Fully optimized route:
estimate trip duration: 34 days
ave boat speed: 3.1 knots
average wind: 13.9 knots
average current drift: .5 knots
average wave height: 4.5 ft
Escape route
Escape from the coast, then optimized:
estimate trip duration: 35.1 days
ave boat speed: 3 knots
average wind: 14.1 knots
average current drift: .5 knots
average wave height: 4.4 ft
So, contrary to what we were previously thinking, it looks like we might be better off going with a route that takes advantage of the tradewinds and currents. It’s more distance, but potentially 30% faster.
Ray Girard on February 25, 2010
You are absolutely correct to allow for current and trades as they have been the downfall of many fairly recent crossing attempts around the world.
Russell Moore on February 25, 2010
Greg, it would seem that a large proportion of the distance covered by rowers/paddlers crossing oceans comes from favourable currents and winds, so why not take advantage of them.
RoninVancouver on February 25, 2010
Hi Greg,
Another point in favor of taking the longer – Escape – route is that you will only touch the outer edge of the Pacific Gyre. There’s a lot of plastic gunk floating around in that area – bags, bottles, ropes, nets, etc – and would add considerable time to your endeavor just cleaning the prop every few hours.
You might get a small taste of that in the next trial if you peddle 50-60nm due west or slightly wnw from the coast of VanIsle. Again, it will depend on wind and current at the time of the test, but still experience is the best teacher.
Right there with you,
Ron
Peter on February 26, 2010
Greg:
I’ve been thinking about this for some time when it comes to human powered ocean crossings and have to ask: What’s your take on the fact that the wind seems to be able to make such a significant contribution to the average speed of such boats?
I personally can’t help but feel that this reduces the “purity” of the attempt in a significant way since it removes it from the ideal of only using human power. Unfortunatly I can’t really see a way to remove the large influence of the wind apart from trying to make the crossing in a human powered submarine. 🙂
For a more concrete example of how this could be a problem in practice: Imagine that you’ve managed to complete the journey and have the record. Later someone else manage to better your time but only because his boat was much less aerodynamic than yours and hence got a greater contribution from the wind. Would that still count as a human powered record or would it be “cheating” and regardless of which, is it even possible to draw a line somewhere between human and wind powered boats that isn’t completely arbitrary?
greg on February 26, 2010
Good point Peter. I know that in the Woodvale race, they all have to use the same ocean row boat design, and they are not allowed to hang up laundry, or use hatches that open upwards or anything that could be thought of as a sail. However, they also have an open category of boat design. See Charlie Pitchers row boat: http://www.transatlanticsolo.com/blog/index.php?id=153 It catches the wind with the low bow and large flat cabin. He is making fantastic time as well.
Murray on February 26, 2010
I suppose the other consideration is the potential negative effect of more wind and the potential damage and subsequent delay that could cause.
David Tangye on February 27, 2010
re “I personally can’t help but feel that this reduces the “purity” of the attempt in a significant way since it removes it from the ideal of only using human power.”
When you get out there you will understand. You will basically be a tiny insignificant spec at the mercy of the sea, currents and winds. The best you will be able to do is plot a course that lets you take advantage of them. That should be your strategy. Anything else is doomed to total failure, unless you are not only the fastest human alive but also the luckiest :-).
Whether you like the “purity” of it on not, you are basically going to be blown and carried to where you want to go. Seamen understand the power of nature out there and work with it. Ignore it at your peril.
Peter on March 3, 2010
David:
You missed my point. I’m in full agreement with you and it’s just that fact that you can’t avoid being significantly affected by the wind, no matter how you design your boat, that i find makes it impossible to make a clear distinction between what should count as human powered versus a wind powered ocean crossing.