The Day Tripper…

I have just finished the shakedown period for my second strip boat, and the first that I have designed and built. The design was completed on kayakfoundry, and thanks to Ross for the program.

The design and build for this boat came out of an inability to get plans for the craft I was after. The closest commercially available boat I saw was the “Duet”, a multisports boat from NZ, and the closest stripper was the Nomad2 from Thomasson design. The criteria were:

1. To be just big enough for the design intent, and no more, which in this case is for a 78kg and a 55 kg paddler, with day gear, or two 78kg paddlers in a bare boat. All other designs were pitched at much bigger people, and normally with capacity for gear. Its design displacement is no more than some of the bigger singles that are available.
2. To weigh about 25 kgs, and no longer than about 6.7 metres.
3. To be stable enough for bays in windy weather, or the open ocean on a “good day”. By a good day I mean typical Sydney summertime conditionals when we get a north easterly sea breeze that builds though the day to about 12-20 knots, and stronger at times, with rideable wind waves typically of 1-2 metres. It is not intended for our more demanding “southerly” conditions, particularly in winter. It is not a surf boat, but needs to be able to punch through waves for a surf exit and land reasonably well. I also wanted to use it on flat water and rivers.
4. To be fast enough for my partner and I to maintain 5 knots on flat water without undue effort, and ideally be quick enough to catch the wind waves created by the sea breeze.
5. To spear through rather than ride over the chop, more like an ocean racing ski than a traditional kayak. For this boat I had in mind the bow of a Fenn Mako ski, rather than a flared, angled sea kayak bow.

I have now done about 300 kms in the boat, mainly on flat water but also in a fast flowing river and most recently in a big bay and the open ocean.

To compare it to the above:

The design displacement is 172kg, and is 6.7 m long and 57 cm wide, 53.5 at the waterline. The waterline lentgh/ width ratio is about 12:1. It weighs 26kgs, fully fitted.

It is OK on the ocean on a good day, but needs concentration. I would not be keen take it in the open ocean in winds over about 25 knots, or in heavy breaking or severe rebound waves. You have to watch the sea state, approaching waves and so on, and use a “predictive” paddling style rather than sit and forget what you are doing.

It is fine in a bay in strong wind. It tracks well but turns like a battleship unless you lean it right over. The rudder is an absolute necessity.

We have done a couple of upstream then down paddles on a narrow, fast flowing river. It went well but on the downstream run care needs to be taken with the wide turning circle. Compared to my other double the reward is an easier ascent and a swift and involving descent.

We have not yet done a serious surf landing, but soon will.

It is really quick. Donna and I are not strong paddlers, but we do have endurance and sound technique. We recently paddled 31 km in 2hrs 45min, a sustained speed of about 11.3 kph (over 6 knots). Maintaining 5 knots is a breeze. Donna and I were about the same speed as our paddling partners (both paddling Mirages), but in this one in the flat or the open ocean we left them far behind. They are now buying a faster boat

What would I change?

If I could, I’d try to build in more stability for the same or a fraction less speed, but it would be a difficult balancing act. I spent forever doing a speed/ stability trade-off with the original design, and it would be hard for me to do much better. I’d certainly redesign the front deck to be straighter in section, rather than the upswept curve that I ended up with. This would give me a bit more water shedding ability and nose lift. I may also make the whole front third of the boat slightly fuller (a higher waterplane coefficient) for the same reason, although I would not like to lose the boats ability to cut though the chop. It could do with maybe a centimetre more rocker to help turning and lift. I can now really see why boat designers build a version ½ and so on before they let it loose on the world.

Other than that, I’m pretty happy. It’s not as forgiving as the Mirage, but is fun to paddle, very quick and was all in all a good project.