Tuesday, June 28, 2011

Rat Island Regatta - Voyage 3

On Saturday I drove with my wife to Fort Worden State Park on the edge of Port Townsend, WA, for the Sound Rowers Rat Island Regatta. No other pedal boats were in attendance. The weather was overcast with temperatures in the upper 50's Fahrenheit, and a light breeze from the south at a couple of mph. Waves were maybe 6 inches or so. For the Admiralty Inlet - the entrance to Puget Sound - this was a pretty calm day.

In preparation for the race I did the following:
1. Shorten the prop strut so when vertical the tip would overlap the stern bottom by about 1.5 inches.
2. Wrap the L-shaped top of the prop strut with a bit of rubber innertube to dampen the shock if the strut moved vertically
3. Slightly bent the remaining vertical strut so as to counteract the propeller torque steering effects that turn the boat to starboard
4. Returned the rear stabilizer support to the lower position, using just the 3/8 inch thick blue foam so the short bolts could be used to secure the mount to the hull
5. Replaced the 152mm crank arms with 170mm crank arms and adjusted the cadence sensor to work with the new cranks
6. Installed a water bottle cage on the bow side of the gearbox
7. Cut 8 inch by 3 inch (approx) rectangles of Coroplast and pentagonal wedges to be taped to the front of the stabilizers for last-ditch water foils should the stabilizers submerge completely
8. Cut closed cell foam pads for the lower back rest and seat bottom

The boat felt pretty unstable at first, but this was merely getting used to how it behaved. The right steering cord kept getting caught by the Coroplast race number I duct-taped to the rear deck behind the seat back - at least until I figured out that using both cords would free it.

The slight breeze at the start coupled with my not carrying a paddle caused me to drift a bit sideways in front of some other boats as we waited for the starting signal. Sorry about that, guys!

Shortly after the start of the race I discovered that the slight tweaking of the prop strut was in fact far overkill. The boat really wanted to turn towards port, and only by deploying the right rudder fully could the boat be brought over to starboard.

This was rather a shame because when the rudders were not deployed the speed of the boat was generally in the 7.5 mph region with a heart rate of about 152 bpm and a cadence of about 68 to 70 rpm.

With the rudder deployed, the speed dropped to 6.2 to 6.3 mph with the same effort expended.

So, I zig-zagged throughout the course, with the rudder deployed about 2/3 to 3/4 of the time.

The prop strut did not seem to bounce up and down any more, or at least not so much as to be annoying. The propeller did ventilate on very minor waves, say 6 inches or so, but only for half a crank cycle or so. I wonder how much of that was augmented by the prop strut.

The bow did a great job of shedding water, and only a couple of times in rougher water did anything make it to the deflector panels below the seat. The foam pad extending beyond the seat bottom panel helped to keep most of the water away from my posterior.

The stabilizers were still a bit stern downward, which probably retarded forward movement somewhat, but at speed the boat seemed to be fairly stable. For whatever reason, the gearbox being slightly off center, the right stabilizer digging deeper into the water, or something else, I found I had to lean to the right to feel centered on the boat. This made for somewhat awkward pedaling, too.

Throughout most of the race I pedaled at 65 to 69 rpm, with a pulse in the 150's, though after rounding Rat Island it started dropping to the 140's. Except for one person in a surfski, the only other folks ahead were rowers. In addition, a person who typically paddled about the same speed as I pedal in a Cadence was some distance behind me in an OC-1.

Trying to reach the water bottle generally required slowing or stopping and leaning far forward to get it, and to return it. A Camelback or similar will need to be installed in the seat back to facilitate drinking on future outings.

At the end of the race I managed to put in a short sprint, almost catching a 4 person rowing shell. My heart rate went to the 160's in the process.

What is funny about all this is that a couple of years ago, and a couple of years before that I finished this same race in a Cadence with almost the exact same time: 1 hour 14 minutes. Considering the new boat was hobbled by counteracting the prop strut steering, this means to me that it definitely has the potential to outperform the Cadence by a significant margin.

After the race I took a wrench and pliers and tried to reduce the tweaking of the prop strut. The boat was returned to the water and yes, it now had less of a tendency to turn to port, but it still needed some course correction.

So, here are the final results:
1. Stabilizers in the rear position work quite well
2. The stabilizers need to drag their sterns less
3. The winglets might have been used, but I couldn't tell - except for some seaweed on one of them.
4. The seat cushions (back and bottom) need work before they will be as comfortable as in the Cadence or Escapade
5. The shorter strut is perhaps 1 or 2 inches too short
6. The prop strut potentially could be a better rudder than the dipping rudders

So, I am thinking of replacing the fixed prop strut with one that rotates. Yes, the current strut can move vertically and allows the shaft to swing from side to side, but if it could be twisted clockwise or counterclockwise then perhaps it could be used for steering.

The effect that a slight twist to a maybe 3/4 inch wide by maybe 16 inch long strip of aluminum had on steering implies that it could be an excellent alternative to the dipping rudders - and drop a couple of pounds from the boat in the process.

Here is a link to the photos taken at the race.

2nd Voyage

A week ago I took the boat out after dinner on Lake Sammamish. The boat is way too heavy, and even with the dolly I used previously with the Cadence it is quite cumbersome to cart from the parking lot to the beach. It probably would be as much of a problem if the gearbox and seat back didn't make the boat so top heavy.

Anyway, this particular beach at the state park had a rather soft, mucky bottom with a lot of weeds. Most of the weeds were eurasian milfoil. Using a canoe paddle to get to deeper water was pretty straightforward and effective.

The 3 inch higher position for the stabilizers (using the honeycomb spacers) in the rear was way too high. The boat was very unstable and flopped to one side or the other. I didn't bother trying to go any distance with them in that position.

After moving the stabilizers to the grab tubes things were a bit better. Unfortunately I drilled the hole for the port stabilizer a bit too far forward, causing the bow of the stabilizer to point slightly downward. When moving forward at any decent speed this acted as a dive plane if I leaned even slightly to the left. I managed to flip the boat a full 180 degrees to the port while turning to the starboard while going at maybe 6 or 7 mph because of this.

No, the seat back does not prevent the boat from flipping completely over. Part of this might have been due to my clipless pedal not releasing my left cycling sandal without a bit of a struggle. Regardless, after placing weight on one of the stabilizers it was possible to right the boat and then carefully climb back on board.

I was able to get back in the seat after the capsize, but from my memories of trying to get back in the Cadence without outriggers in 2+ foot seas and the similar (not quite as bad, but close) roll instability of the V15-6m, I think it could be problematic. Practice will be needed to do this more smoothly and quickly.

The reworked prop shaft has far less friction and operates much more smoothly than before. I was able to get it to turn without clunking for only one sprint - and then it was as smooth as butter and seemed to need very little power to get to over 7.5 mph. Every other time, however, it seemed to go clunk, clunk, clunk at all speeds, or get tangled in weeds that just wouldn't let go.

Yes, weeds wrapped around the shaft, the propeller blades and even the prop strut. Even so, it seemed the boat was able to go 5.5 to 6 mph with quite a ball of stuff on it.

I tried various methods of freeing them using the cranks, forward and/or reverse motion, stop pedaling abruptly, reverse pedaling abruptly, having the blades vertical while coasting, horizontal, at angles, etc. The milfoil manages to wrap itself so tightly that it takes manual intervention to remove.

As an aside, I managed to pick up some weeds on the vertical leading edge
of the bows of the stabilizers, too. Only by stopping would they fall off.
Newer designs with a rounded bow or an angled leading edge would help.

The shaft at the gearbox is not the source of the clunking. The joint there is rotating smoothly. The problem is definitely at the propeller end of the shaft.

My first thought was that weeds were the cause of the clunking, but this happens even with a weed-free prop and strut.

So, now I am thinking of wrapping the strut support with an inner tube in case it is due to the strut moving up and down.

As an aside, reverse seems less effective than with the longer and straighter shaft. It at least 20 or 30 rapid turns of the crank to reach 3 mph.

So, I think I'll go back to the original height of the stabilizers in the rear position. The boat seemed to be much more stable with them there, with their tails dragging slightly. In addition, I think the addition of some short wings near the bows of the stabilizers angled upward will help when moving at speed to keep the stabilizers from digging into the water when downward forces are applied to them. It was somewhat nerve wracking to get going to a nice speed (7+ mph) and then have to back off because the stabilizer was starting to dive into a really minor wave - and keep going under.

On my last run I made sure there were no weeds on the propeller and shaft, trying to pedal in circles and still it clunked. It could be the shaft not finding a good fixed position in the stuffing box. If so, then adding a Delrin plain bearing might just do the trick.

So, if the stabilizer wings and Delrin bearings don't work, I'd have to say that I wouldn't trust taking this boat on any but the tamest waters, and certainly not on anything lengthy. No photography from the boat, either - at least not until I get a purpose-built waterproof camera. Right now I wouldn't trust this boat and the Ewa Marine waterproof case enclosed camera.

Steering is not much different from the first trial. I'll try Rick's suggestion of tweaking the angle of the prop strut to apply a constant course correction to the port.

Saturday, June 11, 2011

Maiden Voyage!

In preparation for the maiden voyage I decided to make some higher spacers to test with the outriggers. Searching my garage for some likely materials, I found a couple of 2x4s, including some pressure treated lumber, but thought that this stuff was pretty heavy. Going over to a box of would-be firewood, the pieces in there were too thin or the wrong shape. What to do?

All of a sudden I had an idea: The big hunk of phenolic honeycomb I had picked up years ago from a friend would be perfect!

This was a 5 foot by 2 foot by 4 inch thick piece that had a taper cut off the one corner of the long dimension, but was otherwise perfectly rectangular in shape. It was also just small enough to fit in my bandsaw to cut a chunk that could then be sized to fit as a sandwich between the deck and the outrigger support.

It was a little tougher to cut than I thought. The material tended to bind the bandsaw blade and the blade came come off the wheels a couple times. Eventually I figured out that I needed to cut the material at an angle rather than through one cell at a time.

The results were pretty good. Positioning and drilling the holes was a little strange as you can't really mark the center of a hole to be drilled when it is in air, though upon reflection it could be done using a sacrificial sheet of paper. Anyway, holes were drilled and things fit quite nicely. Unfortunately, none of the 1/4-20 bolts I had available were long enough to reach. A trip to the hardware store was necessary - but that wasn't going to happen until *after* the trip to the water. Oh, well.

The boat fit quite well on top of the Toyota Matrix with the Thule racks, with the stabilizer floats lashed to the second set of saddles. The propeller dangled several feet beyond the stern, but a safety flag was added to make sure it was legal.

After driving to Idylwood Park my wife and I carried the boat and the rest of the stuff to the shore in two trips, resting the boat on a picnic table by the beach. Assembly of the outriggers went quickly. The foam for the lower seat back was a bit of an issue. I ended up folding some closed cell foam and duct taping it to the seat back so it wouldn't come apart, fall off or get in the way of the steering cords or the grab tubes.

A safety canoe paddle was duct taped to the side of the seat for insurance.

After setting up the camcorder on its tripod and giving my wife last minute instructions for the camera, we carried the boat into the water.

Even though we have not had much warm weather this year, the temperature of the water was not too cold. With the propeller just above the bottom of the lake the bow was a couple of feet from the shore. I was able to lift myself up onto the seat cushion and then put my bike shoes on the Speedplay Frog pedals.

The boat was slightly lower in the water than called for in the original plan, with the stabilizers both touching the water at their tails up to about the midpoint of their length. The honeycomb spacers should be just about perfect to keep them above the water.

Gently pedaling in reverse I backed away from the shore. Clunk, clunk, clunk went the propeller and shaft.

After getting about 50 feet from shore I tried pedaling forward, with the port rudder fully deployed. The boat headed almost straight back to shore. Uh-oh - this was not good!

I reversed direction. At first there was a moderately significant effort to pedal, but suddenly it shifted into an easier mode. Did something break or fall off?

No, but it is possible that the propeller blades swung into fully deployed mode. I was soon going in reverse at 3.5 mph.

I tried steering while going in reverse. That was nearly worthless, too. Going forward again, the boat slowly turned before reaching shore.

One more time and I was finally parallel to the shore, and ready to start the speed trials.

By this time I realized that the seat back cushion was a bit too thick, and that the cranks were too close to the seat back. My legs were not having proper leg extension. I'd have to make adjustments when I returned to shore where the wrenches had been left.

Meanwhile, I pushed on. The pedaling action was quite stiff, but soon things seemed to smooth somewhat. According to the Garmin 305 GPS watch the boat reached 7.5 mph ridiculously quickly. At that point the speed seemed to bounce all over the place. It dropped to 7, went up to 8 and back down to 7.5 mph. It was pretty strange, so I decided to ignore it and concentrate on steering and other boat handling aspects.

The lake was pretty calm, though once in a while a ski boat zoomed by off in the distance. So, in general, the lake was flat and the breeze was perhaps a couple of mph from the north.

I tried turning to port, pedaling somewhere around 7 mph, and fully deploying the rudder. The boat was very slow to respond, so I tried leaning over to the side to see if that helped. If it helped I couldn't detect much of a difference.

Eventually the boat managed to make a complete circle and I headed back to shore. It was actually quite a bit of effort, and there was a definite bow wave produced.

At the beach I got off and reported my findings to my wife and a young couple that had been curious about the boat. I offered a ride to them and the man agreed to go. He took off his shoes, put on the PFD, and pedaled away from shore.

He made a semicircle trying to head back, leaned too far and found himself in the water! Oh, no!

It didn't take him too long to swim with the boat back to shore where we had a towel waiting for him.

I prepared the boat to go out again, found that I needed another wrench to adjust the gearbox position (rats!), and cleared the ball of milfoil he had collected from the propeller. This was going to be the last run of the day and I wanted to go a mile or so around the north end of the lake.

After paddling in reverse with my hands away from shore I turned the boat around and headed north. I then headed northeast through the 1.5 foot wake generated by a passing ski boat. The sharp hull and deck sliced through the water like a knife, and there was enough lift generated that the hull was raised enough to slap down on the surface beyond the waves. This was not too bad.

The action of the rear positioned stabilizers will take some getting used to, however. Not seeing the source of the lifting action against the floats and having the boat jostle one way or the other was a little unnerving.

Anyway, I turned around and aimed back toward the park. Going in reverse to try to ensure no weeds were on the prop and then forward I quickly got up to speed. Again, the top speed was about 7.5 mph, though the stabilizers were dragging somewhat. My cadence was about 76 RPM, which is a little slower than I would like for the level of effort being expended. My heart rate was in the upper 130's to low 140's, so this was a pretty significant improvement over the performance in a Cadence pedal boat.

There was a light breeze on my face as the boat seemed to race through the cottonwood seeds floating on the water. This boat could move pretty well!

With no rudder deployment the boat tended to turn towards starboard. Leaning to port had little effect. The port rudder had to be used quite frequently to maintain a proper heading.

I soon reached the park - just in time for a set of ski boat waves to hit the beach. No problem - I back off a little and waited for it to settle before enlisting my wife in getting the boat from the water.

1. This boat is not as stable as a Cadence with outriggers
2. It seems to be about 1 to 1.5 mph faster than a Cadence with outriggers
3. The draft is significantly deeper than that of a Cadence
4. The deck is far, far better in sloughing off waves
5. The steering is far, far worse than almost any other boat I've been in
6. I need to figure out ways to launch it, load it on the car and take it off by myself
7. I need to sand it in broad daylight rather than in the garage. I was amazed to see the number and distribution of resin drips, etc., that I missed sanding.
8. The steering deployment using cords and stretch cord return worked flawlessly, as did the prop strut.
9. The prop shaft needs to be redone completely. I think there was excess friction in the stuffing box, and the flopping shaft robbed energy that could go into propulsion.

Sunday, June 05, 2011

All But the Final Clearcoat

Bits and pieces were completed during the week. With the successful testing of the T-nut I decided to use them to hold the prop strut bracket. However, due to the narrow taper of the stern, I bent the flange of one slightly so it wouldn't stick out when filleted in place close to the stern. The fillet material also refused to form a nice, smooth surface, so I figured that it would just get sanded with the Moto-tool once it hardened.

Additional sanding was done on the rudders, amas, stern deck and aka support areas. I removed the drips in the resin from the fore deck, too. Holes were drilled in the rudder control arms for the stretch and non-stretch cords. Afterwards, I applied a thin coat of resin to the recently glassed areas, and then thinned the remaining resin with lacquer thinner per the instructions of Vern Heikkala as well as the folks at System 3. The thinned resin had the viscosity of water, and was applied to all the sanded areas to give it one last glossy coating.

The prop strut bracket was made from a single U-channel of aluminum, 1 by 1 inch by 1/8 inch thickness. A slot was cut near one end to hold the strut, and holes drilled to align with the T-nuts just added to the stern deck.

I tried drilling another bushing for the coupler between the gearbox and the prop shaft, but this attempt was also unsuccessful. So, with shrink wrap plastic I tightly wrapped the end of the 0.625 inch diameter tube that was being used for the prop shaft and jammed it down the middle of a 3 inch long stainless tube that was chosen for a coupler that I had filled with fillet material. This actually worked fairly well.

A couple of days later the next steps were to sand the excess resin from the rudders and the rudder bearings, and mount the cheeks (pulleys) on either side of the stern.

After running some tests with the lightest stretch cord I decided that using a single dead eye would be enough to pull down both rudders. There was too much friction to using the dead eyes as stretch cord guides, and I didn't want to add another pair of cheeks. Running the deployment cords over the top of the rudder bearing and over the top of the aka support removed the need to use dead eyes to guide them, too. There is a little friction to consider at the top of the rudder bearings, so it is possible the cord will wear. An application of resin there would help smooth things out.

I made loops at the ends of the cords so they would hang on the grab tube. The loops are long enough so that the rudders could be deployed fully and no more by merely pulling on the loop as far as it would go. Releasing the loop would allow the stretch cord to return the rudder to the stowed position.

Since I wanted the left side to also be able to control the right rudder I added a second control line with a knot at the end to distinguish it from the left rudder. It all seems to work well in the workshop.

The gearbox was mounted and bolted into place.

The aka supports were raised about 3/8 inch to be slightly higher than the tops of the large T-nuts. The space was filled with pieces of foam - at least until I figure out an alternative spacer.

Holes were drilled through the top of the aka support tube into the two akas. This is for the two 3/8" diameter push buttons that secure the akas to the aka support tube.

The amas were then mounted on the akas. Since they were mounted closer to their bows their sterns needed to be supported so the holes for the pins used to secure the amas to the akas could be drilled. I made sure to account for preloading the amas so they wouldn't drag their sterns while on the water.

I completed the propeller, too. The blades needed a bit of grinding at the hub so they would fit properly in the hub that Rick sent me. Once that was done everything went pretty smoothly. It was good I had a nice assortment of drill bits, including a size "W" bit to enlarge the bore to fit my almost but slightly larger than 3/8 inch diameter shaft.

The propeller was then mounted to the shaft, and the shaft connected to the gearbox via the coupler. I had to use the drill press to cut the holes. The hand held drill just didn't have adequate pressure to do the job.

A prop shaft strut was cut from a larger piece of 1/8" aluminum sheet. I cut it in the shape of an "L" so that overhang could be used in place of a bolt to retain the strut in the support bracket. The other end was essentially riveted to a plastic bushing that supported the propeller shaft.

So, with the exception of the final clear coat the boat is ready to go!

I really was hoping to launch this weekend, but with various family activities and having to search for quite some time for a couple of things that apparently fell to the bottom of a trash basket took their toll. I did get some weights, however:
Amas and akas: 6 pounds each set, 12 pounds total
Main hull: 35 pounds stern, 31.5 pounds bow, 66.5 pounds total
All up weight: 78.5 pounds

Note: The propeller shaft is at least 2 feet longer than it needs to be. I am going to see how badly it vibrates in practice as the joint between the tube and the rod are definitely not concentric. The extra length of rod+tube is about a pound, possibly more.

Sigh...this is only 15 to 20 pounds lighter than the carbon fiber Cadence (with outriggers) I used to have. While it is lighter than a standard Cadence without outriggers it is nowhere near where I wanted this boat to be; i.e., in the 50 to 60 pound range.

I think that using 4mm plywood is almost certainly overkill, especially if the more highly stressed areas are glassed on both sides.

Still, the resin coated wood makes for an absolutely gorgeous finish, and the material cost is considerably less.

We'll just have to see how well it performs.