X-Boat Trials

or what to do with your old sprint K-2

Spring and Summer 2003 Diary

2004 Diary

2006 Diary

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I modified my old K-2 so I could paddle it solo.  Since I also like paddling canoe, I also modified it so I can paddle it as a canoe.  Just out of curiosity, what would happen if I put a sliding seat in the boat so I could use my legs on each canoe stroke?  I rigged the boat so I could do all three and be able to change without getting out of the boat.


My K-2 sprint kayak was purchased used in 1976.  It had been gathering dust and deck stain as it was stored under our backyard deck.  I had decided my downriver kayak (Prijon87) lacked the roominess that I needed for recreational fitness paddling so I converted the K-2 into a roomy K-1 that could carry gear.  Since the hull was designed to carry two people it should be able to carry me and some gear. 

April 20, 2003 - Paddle the X Boat as kayak without stabilizers and with downriver seat.  Max 7.5 mph.

April 23, 2003 - Stabilizers arrive from http://www.canoegear.com/ so I go to the lake to try X Boat under chilly, windy conditions.  In order to sit high enough for single blade the stabilizers keep the boat from being to tippy.  Try it single blade with fixed seat and with sliding seat.  I think this is going to work.  Back to the shop for adjustments.

April 27, 2003 - Took the X Boat to the lake and paddled some short trial runs as kayak and canoe.  After a few adjustments I tried a couple of short sprints with GPS on board to measure max speed.   Here is a video of that trial: X-Boat Trial No.1 (video 7 MB download)  Windows Media Player compatible

April 29, 2003 - Paddled X Boat five miles single blade with sliding seat. I had to spend the first couple miles adjusting my foot straps and the height of the floats.  Once I got that straightened out I cruised comfortably at about 5.0 mph.  Floats were set at one inch below the stabilizer bar.   I need to raise the stabilizer bar and build some steamlined floats.

April 30, 2003 - Windy, chilly conditions. Paddled K-1 five miles. Max 7.4 Avg 5.5 with a few stops. Whew! I'm not in kayak paddling shape!

Need to get the downriver seat mounted. Just screw it to the redwood 2x2s that sit in the channels? My seat got pretty tired at about one hour on current seat.

Boat got way too much water in it. Need to deck it over. Hope it was all from the paddle and spray.

Look into getting some knee straps like they use on the sit-on-tops kayaks.

Either move the stabilzer forward and up, or mount stabilizer on kayak risers on rear deck. I think the risers are required no matter where the stabilizer gets mounted. Paddle the kayak without the stabilizers is certainly an option, but they are nice if I want to stop paddling and relax.  Sitting at the current height off the water is perfect, but might be too tippy in rough water without the stabilizers.

Build hydrodynamic floats.

May 1, 2003 - Started making new floats.  Did more streamlining on original floats.  Investigating possibility of easy to apply slick finish on floats.   Mounted stabilizer on rear deck.  Thinking about building a cedar strip curved deck for oversized cockpit front and rear with hatch doors.

May 2, 2003 - Paddled C-1 for 2.5 miles in 27:51.  Max 6.8 mph.  Warm, slight breeze allowing 5.8 to 6.0 with wind and 4.8 to 5.0 against the wind.  Stabilizers on rear deck.  Floats 2 inches below bar.  Too much water getting into the boat.

COURSE DESCRIPTION:  A course description is in order, because I will be continually referring to our 2.5 mile course.  The course is at Colorado River State Park - Connected Lakes on two small lakes connected by a channel.  We've been using this course over the years with a stop watch.  Last year we started using a GPS for more accuracy because the course has many turns and it is easy to cut corners to shorten the course.  Last year we started using a GPS to measure 2.5 miles each lap.   A lap consists of two figure eight laps around the lakes with reversed direction on the second lap.  All total there are about six 180 degree turns.  Every turn slows the boat down so average speeds are slower than would be on a straight course.  The X boat, in spite of being over 21 feet long, turns better than most boats I've used thanks to its rudder and bouyancy with only one paddler in this two man boat.  In the picture below you can see the two connected Lakes and the Colorado River on the right.

Course.bmp (330066 bytes)

  May 3, 2003 - Decided the rudder was the source of the leak.  Removed the rudder, cleaned it and reinstalled it with Bondo and Kevlar.   Also added a patch of Kevlar to plug hole in the boat where a venturi speedometer once resided long ago.  Looks like no paddling this boat this weekend.

May 9, 2003 - Paddled the X Boat C-1 with sliding seat and fixed seat in windy conditions for five miles.  No data collected.  Changed from sliding seat to fixed seat a couple of times and only missed a couple of strokes in the transition.  Sliding seat requires concentration.  Operating the rudder while sliding is tricky.  One slider stroke seems to turn the boat more than with fixed seat, possibly because of a longer stroke.   At one point while quartering a tailwind, the wind waves caught a pontoon and turned it sideways.  I was able to reach back with the paddle to straighten it.  The post twisted in the stabilizer because it wasn't tightened adequately when I started.  This boat handles very well in the wind.  It is nice to be able to transition between fixed seat and sliding seat without stopping.  It feels good to be able to use the legs with the sliding seat. Stabilizers on rear deck.  Floats 2 inches below bar.

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May 10 > May 19: Took a break from the X Boat to paddle normal boats on the river.

May 20, 2003 - Paddled the X Boat K-1.  Started with stabilizers set at 48 inches as shown in the pictures above.  Floats set 0" below bar.   Tried the downriver seat on top of the web canoe seat.  Didn't work because the seat was tipped too far back.  Removed the downriver seat and sat on the web canoe seat five inches high.  With the stabilizers at 48 and 0 the boat was too tippy, so I extended the stabilizers to maximum and left floats at 0.  This made all the difference in the world.  The extended stabilizer bar made the boat very stabile even though the floats were not in the water.  (Think "moment of inertia" like a tight rope walker using a long pole to balance himself.)  GPS registered a max of 8.1 MPH and cruised at 6.0 MPH.  This is a very nice kayak to paddle with its speed, maneuverability, and stability.  Need to build a deck for rough water conditions.

July 10, 2003: After paddling rivers during spring runoff I finally got back to the X-Boat today.  Breeze.  X-Boat C-1 max speed 7.0 MPH.  28:08 with some stops.  The boat handled well.  X-Boat K-1 using wood sprint seat.  This worked well.  Max speed 8.0 MPH.  Had to stop for rests. 28:08 same time by coincidence. 

July 12, 2003:  Paddle K-1 five miles.  Cruise at about 6 mph on straight away and 5.2 on turns.  Still getting lots of water in the boat.  Is it leaking or is it paddle splash due to no deck behind the paddler? 

October 19, 2003: Last night I dreamed about the X-Boat.  I dreamed someone mistakenly thought they were supposed to take the boat from my garage and transport it to California.  I dreamt this over and over again.  Each time I would awaken from this nightmare worried and upset that the boat would be screwed up by this guy.   Finally I awakened enough to realize it was only a dream and that the X-boat was safe in the garage.  I knew it was time to take the boat out for a paddle and continue working on it after a good summer of paddling C-2 with Marci.

I took the boat to the lake to get some video of it with the sliding seat in operation.  The boat paddled very well with the sliding seat, fixed seat, and kayak paddle.  The sliding seat configuration has real potential.  With the sliding seat it seemed easier to maintain the same speed as with the fixed seat.  I have the least experience with the sliding seat and am optimistic that it will be the most efficient way to paddle the boat in the long run. 

Need to build some streamlined floats for the stabilizers.  Back in July I poured enough water into the boat while at home and determined that the leak was under the rudder.  I filled the leak with resin and micro-balloons (Bondo putty) and this time out it appears that 90% of the leak has been stopped.

Sliding seat in action video ( 3 MB download, Windows Media Player Compatible)

Another sliding seat in action video ( 7.3 MB download, Windows Media Player Compatible)

Kayak video ( 3.4 MB download, Windows Media Player Compatible)

Fixed seat demo ( 2 MB download, Windows Media Player Compatible)

New float demo (325 KB download, Windows Media Player Compatible)

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10_19_2003 3_06 PM_0002.jpg (23209 bytes)