Drama on the Yukon
 by Skip Johnson - Houston, Texas - USA

I really should be finishing up some real work, but the “Coureur des Bayou” is leaving Carnacks at the moment and I feel compelled to start this article as the drama is playing out in the Yukon. The “Boys from the Bayou” have a slim 14 minute lead over the second place boat after 325km of hard charge racing. The balance of the lead boats are clustered around an hour and a half back, 4 boats within 26 minutes of each other.

As always, it is paddlers that win races, the boat is but a tool they use in the endeavor. This is about the design and building of such a tool, a Voyageur for the Boys from the Bayou.

The Design

When Richard Ameen approached me last year about designing a Voyageur for the Yukon River Quest, the only question was, “how many paddlers are you going to have?” Once the governing body finalized the rules, we had a choice of 3 sizes within the class.

(A) 28’ LOA, 36” minimum beam at the 6” waterline
(B) 34’ LOA, 44” minimum beam at the 6” waterline
(C) 42’ LOA, 48” minimum beam at the 6” waterline

In each case the boat had to be a minimum of 18 inches deep at the gunnels, 6 man minimum, single blade paddles.

Preliminary calculations ran out that the 28’ boat wanted a 6 man crew, the 34’ boat an 8 man crew and the 42’ boat 14 paddlers.

The biggest size was dropped from consideration, too many people involved, the other two sizes have virtually identical L/B ratios (9.33 and 9.27) so the decision was based on the number of premier paddlers Richard could recruit for the effort. Eight it is. Based on previous ruminations with Texas Water Safari boats, the paddlers equivalent to the drag racers “there’s no substitute for cubic inches” holds true but there is diminishing returns as you add paddlers past 5 or 6. Still a 34-foot long boat should be better/quicker than 28 footer. Particularly since there are no portages or really twisty narrow spots in this race.

Weight estimates and fixed dimensions in hand preliminary design is pretty straightforward. 6” by 44” midsection times about .8 gives a midsection of 1.47 square feet times a length of 34 feet with a prismatic coefficient of 0.50 equals 24.93 cubic feet or 1556 fresh water pounds. Dead on, just less than 200#/paddler which is a little conservative, since these guys don’t carry any extra weight on their persons.

To squeeze the last little bit of drag out of the boat a number of Godzilla optimization routines were run through Mitchlet to fine tune the shape below the waterline. A graph of relative drag is included for those interested in the fiddling details [see below]. The graph compared the drag versus speed for a single paddler in four different boats. The 2 man shallow water data was included just because it was handy and adds a little perspective to the forces involved. The cyan ‘base’ curve is a non optimized but generally well shaped 8 man voyageur (preliminary design) . Yellow curve is the optimized shape for the same boat. The brown curve for a paddler in a 6 man safari style boat shows the difference a little beam makes. Up to about the 24th tick on the speed scale, (about 6mph) The Voyageur has an advantage based on relatively smaller wetted surface. Then the smaller cross section of the Safari boat makes less waves and will pull away from the voyageurs if all the paddlers are putting out a constant force of 0.02 kilonewtons.

 I have included this graph of relative drag for those interested in the fiddling details - click the image at left for the PDF file.

Please take all this with a large grain of salt. The graph is a reasonable reflection of reality but doesn’t take into consideration our theoretical paddlers training, heredity or heart, which will trump any increase or decrease in area under a graph. Still its good to give these paddlers the best boat possible.

Once the underwater shape is fixed it is time to shape the topsides which is primarily adding some tumblehome to the center of the boat and flaring out a ‘sterncastle’ in the stern to get the steersman paddler as far aft as possible. In this case there is enough depth in the bow to decide that no extra bumps or flares are needed for extra volume. In this particular case I did the tumblehome section three times.

First time I rolled the sections to a parallel line on the basis that it would be the easiest for George to cut out all those patterns. George is something of a perfectionist, and thought the boat would be better if it didn’t have that ‘hard spot’ where the sections transitioned from natural to rolled. The sections were redone in that area and stripping started. Still doesn’t look quite right…. Finally I redo the sections the way they should have been done in the first place and building commences.

The Build

 George with boat - Foam is stripped over male form much like a conventional stripper.

Kevlar, carbon fiber and a touch of s-glass each side of 3/8” (9mm) 5#/cubic foot divinylcell foam. Foam is stripped over male form much like a conventional stripper. Outer skin is laid up, carbon fiber followed by s-glass and smoothed up with a layer if peel ply. A large crew required for layup operation, in the picture left to right, Richard Ameen, Wade Binion, John Hoffart, George Melder, all team members and Gary Kohut on far side of boat. Present but not in picture, John Qualls, team member and yours truly who usually shows up and mixes epoxy at these events.

 Outer skin is laid up - left to right, Richard Ameen, Wade Binion, John Hoffart, George Melder, all team members and Gary Kohut on far side of boat.
 Once the outer skin has cured, the boat is taken off the form and prepped for the inside laminate

Once the outer skin has cured, the boat is taken off the form and prepped for the inside laminate. Then the inside laminate is applied, kevlar, and a blend of carbon/s-glass. If anything, applying the inside laminate is a little more frenzied process than applying the outer, witness no one took any good pictures but I believe there were 8 of us. The interior laminate is vacuum bagged which entails adding a couple of lavers of bleeder cloth and absorption material over laminate and then wrapping the whole boat in a nylon bag and applying a vacuum (5-7 psi) to consolidate the laminate and remove any excess resin.

 Then inside laminate applied, kevlar, and a blend of carbon/s-glass.

At this point the hull is done except for some trim work, gunnel reinforcing and the like. I was of the opinion that the boat needed to have a couple of bulkheads in the middle of the boat (like the plans showed) to stiffen the hull and keep the gunnels from panting (moving in and out). Turned out that with the seat braces in place, no matter how hard you pushed and pulled, the gunnels just stayed in place. Amazing stiffness with all that carbon fiber.

Rigging

In many respects a voyageur is simpler than a safari boat, light requirements are minimal, it is after all going to race in the land of the midnight sun. Gear requirements are different but there is an enormous amount of room available, particularly compared to a safari boat. The big question regarding rigging was the seating setup. All the crew had read an outstanding article by one of last years top voyageur finishers and the description of switching from side to side on bench seats was a matter of some concern. These guys hate to miss a single stroke and the thought of missing several strokes while clambering around every 50 or so strokes was the stuff of nightmares. George asked me if I thought that there was room to have everybody in a line and after a quick check, the answer was yes, actually there was plenty of room. Then George had a brilliant idea, make the center seats slide from side to side, so its quicker and easier to swap sides, and by the way not miss a stroke….ever. The lateral sliding seats used in the center 4 positions were elegantly executed using hardware for an exercise rowing machine.

 Then George had a brilliant idea, make the center seats slide from side to side, so its quicker and easier to swap sides, and by the way not miss a stroke….ever.

Since this was a new innovation, the boys asked me to hold off writing anything about the boat until they actually raced it. A reasonable request, actually they paddle faster than I write and now have won the 2007 Yukon River Quest in a record time 41hrs 15 min unofficially, one hour one minute ahead of the second place boat. The lateral sliding seats may have helped, but they won with teamwork and heart.

Interestingly initial trials brought to light one aspect of the lateral sliding seats no one had considered beforehand. If you miss hearing the call to hut (switch), the boat will heel to your side when there are suddenly 3 people on one side and only one on the other. Then is a long way uphill to slide to get to the proper side. Apparently every one learns this quickly and it is not a problem. Do note though that the one time this designer was in the boat, I’m in one of the fixed seats [TRIAL TWO].

 If you miss hearing the call to hut (switch), the boat will heel to your side when there are suddenly 3 people on one side and only one on the other...
 Apparently every one learns this quickly and it is not a problem. Do note though that the one time this designer was in the boat, I’m in one of the fixed seats - second from the front.

Last Practice

Susie had allowed that she hadn’t seen the new boat and would like to see it in the water before it left for points north. We went up to Lake Conroe and watched the last practice, which included all the Texas team members plus a couple of good local paddlers to fill in for the two team members from the Northwest

Pictures and captions

 That’s a full size pickup
 Half the crew can easily move the boat
 About 3 boat lengths and they are up to speed; probably exceeding the marina speed limit but not leaving a wake.
 Note that everyone except Grady has changed position and was surely done without slowing down.
 Off to the Yukon

Postscript

A new voyageur record, the first time a voyageur had won first place, beating two local favorites that expected to win the race, heady accomplishments for a team that hadn’t been there before.

Kudos to:
Richard Ameen, who put it all together
George Melder, builder extraordinary
The two Johns, Qualls and Hoffart
Pete and Wade Binion, father and son
(Pete did a paddlers trifecta this year, 1st masters-Ruta Maya, 1ST TWS, 1st YRQ)
Edoh Amiran, navigator extraordinary
Liam Price, steersman

I’m honored to have helped in a small way.

 The winners - courtesy of Yukonriverquest.com

Other articles by Skip Johnson:

 SAILS PLANS EPOXY HARDWARE CANOE/KAYAK SAILMAKING MATERIALS MEDIA TOOLS GEAR
 Navigation Lights Rubber Pole Clips Bimini Hardware