Monday, September 26, 2011

Budd Inlet and Lake Samish Races

I've had the boat at two Sound Rowers races since replacing the fixed strut with the steerable strut. The dipping rudders have remained in place for both races, but were used very infrequently - and then mostly as a test to see how well they performed.

At Budd I found that maneuvering around in the marina area the strut rudder performed quite well, even at very low speeds such as while docking. The dipping rudders were still next to worthless, though when I wanted to turn more quickly than the strut permitted they did help a little.

The Budd race otherwise showed that the strut rudder worked well even in 1 to nearly 2 foot chop. There were very few times when the propeller aerated with the rudder at full turn. It worked quite well to counteract weather cocking when heading into or to slightly to either side of a 15 knot headwind and the waves it produced.

My stats from the Budd Inlet race.

The Lake Samish race was quite flat with only a light breeze for cooling. Surprisingly, at this race turning the rudder to the limits caused aeration of the propeller. Perhaps the difference between salt and fresh water density made the difference. Otherwise, the only other variable I can think of is that somewhere along the course some filamentous weeds managed to wrap themselves around the propeller shaft and hub.

The dipping rudders were used only a couple of times; i.e., at each of the turn buoys. I didn't notice any difference with the changed starboard rudder angle, except that perhaps it didn't drag so much or turn as well.

Otherwise, the boat handled well at both events and was quite popular among the people present. It made the Bellingham Herald newspaper at the Lake Samish race (photo) and an interview, though the part about where the design came from didn't make it to the article. My apologies, Rick, but the press doesn't always tell the full story!

At any rate, it appears that this year's race was a personal best, and possibly a pedal boating record for the course with a time of 49:52 for 5.5 miles distance. Of course, taking some 900+ photos (edited down to 880), made the race a bit slower than otherwise one could go, and the reverse course was not as short as that traveled by the other competitors. However, this was about the same as for years when I pedaled the Cadence, taking photos as well - though with an easier to use camera.

My stats from the Lake Samish race.

As an aside, at the Bainbridge Island Marathon where I did the half marathon and completely bonked - I still ended up with a new class record with a time of 2:05:59! Hurray!

Thursday, September 08, 2011

Strut Rudder results

I am quite happy with the improvement in steering provided by the strut rudder. It seems to be far more effective than the dipping rudders in turning the boat. When both a dipping rudder and the strut rudder are used to turn in the desired direction the boat is almost able to be controlled to a reasonable extent. Of course, it is nowhere near as maneuverable as the Cadence and far from the maneuverability of the Escapade, both of which have the advantage of propeller thrust against the rudder. Still, it is an excellent improvement.

I found that the nylon tie was getting abraded by the aluminum on both the rudder and the strut bearing bracket. This was due to the fairly sharp edges on both. I have since rounded the edges of the hole in the rudder through which the nylon tie goes. The strut bearing bracket will have a second nylon tie over which the supporting nylon tie will nest. This way the inner tie can be tightly held to the aluminum bracket and provide a smoother bearing surface for the tie under tension holding the prop shaft to the rudder.

+/- 20 degrees appears to be all that is needed. In fact, turning the rudder slightly less than 20 degrees significantly reduces the aeration of the propeller.

Cruising speed seems to be either unaffected or possibly very slightly slower. However, not having to adjust course by dipping the rudder should make overall speed better.

Will I remove the dipping rudders? Right now I'm not sure. There are times when having the extra rudders for a somewhat tighter turn makes life easier. I also have to see if the nylon ties have an adequate lifespan to place all my trust in the strut rudder. Otherwise, an alternate mechanism or material will have to be used.

I still have to replace the prop shaft with one that is not bent. That project is nearly done as the tubing and rod were cut to proper length and bonded last night with fillet material and cloth. After it has set for two days I'll drill a hole through the diameter of the tubing and insert a stainless pin to make doubly certain they stay together.

I expect cruising speed to be a little higher and be able to maintain it for a longer time.

Work has begun on modifying the dipping rudders to have a 20 to 25 degree angle rather than the 40 degree angle they currently have. This involves cutting the fillet and glass securing the wood pieces to the fiberglass tubing and re-adhering them at the proper angle. This should be done in a week or three.

Meanwhile, I'll give it a try with just the strut rudder for the next race.

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Saturday, September 03, 2011

Seat cushion and new rudder

I just made and will try out in next week's race seat covers for the foam. While I was going to use garden cloth it appears that stuff isn't quite as strong as I expected. There is a mesh but a lot of the fibers are merely a mat and don't impart much strength.

The material I ended up using is a garden plastic, with push-through perforations every 1/16 inch or so. One side is somewhat slick, but the push-through side is moderately high friction. Anyway, I cut it roughly to size and welded/cut it to final size with the electric shrink wrap sealer. With the perforations pointing outward I think it will drain fairly well. It took all of 10 minutes work, cutting/sealing two sides, turning it inside out, stuffing in the foam and sealing the remaining edge.

This stuff seems to be fairly tough, and should last for quite a while.

I also purchased some "industrial strength" adhesive backed velcro to secure the cushions to the boat. The vertical orientation of the 2 inch wide seat back strips will allow some vertical adjustment to accommodate the position of the PFD. My spine was rather sore after the last two races due to a gap between the cushion and the lower edge of the PFD.

In preparation for the next race I have replaced the prop strut with a foil shaped rudder. The foil is something I found online a couple of years ago for use in making rudders for a different boat. It is aluminum, about 3/8 inch thick at the thickest point, and about 2-3/4 inches wide. Taking some scrap anodized aluminum I salvaged from some ancient office partitions years ago I cut a triangular hole near one end to accommodate the rudder and its intended range of motion port and starboard. This replaces the U-channel prop strut holder previously installed.

I cut a two armed tiller from 1/8 inch aluminum sheet. This has a foil-shaped slot to control the turning of the rudder, and allow it to not impede the rudder from moving vertically.

The foil was cut to about 17 inches length, with a notch cut from the bottom so as to surround the tab supporting the prop strut bearing. A 1/4 inch hole was drilled just above the notch and two holes cut at 1 and two inches from the opposite end. The bottom hole had a heavy duty nylon tie wrap looped through it and the hole in the prop strut bearing tab, with a slight amount of slack enabling the rudder to twist port and starboard.

A 3/4 inch bolt was inserted through the top hole and a nylock nut used to secure it. This is used to prevent the rudder from dropping through the tiller slot.

A small hole was drilled about midway down the rudder. This is to be used when lifting and holding the propeller shaft in its upper position for shore-side transport by inserting a pin.

Another synthetic cord was tied from one tiller arm, threaded through the same dead eyes as are used for the dipping rudder shock cords, stretched to the left grab tube, and back to the other tiller arm through the other dead eye. Control of the strut rudder is by pulling the top of the cord for starboard and by pulling the bottom of the same cord for port.

Due to the width of the strut support the rudder is limited to +/- 20 degrees.

I hope to give it a try this holiday weekend.

If the rudder/strut works, I'll consider replacing it with a lighter wood/aluminum core or glass/foam/aluminum core foil. This would use the original (or equivalent) strut for the core. I might also replace the strut support with one that allows a wider range of motion, e.g., +/- 30 degrees.

If it works really well the dipping rudders will be history. This should reduce the windage steering encountered at the last two races.

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Friday, September 02, 2011

Great Cross Sound Race

Last Saturday I raced in the Great Cross Sound Race, but in the reverse direction from the other racers. The venue was far less crowded so far as larger craft were concerned, and there was not much wind (maybe 5-10 knots from the north). The tide was ebbing (heading north), and the first part of the race the water was pretty calm with maybe 1 foot waves. The waves were not all from the same direction, and from the middle of the Sound to Bainbridge it was messy again. The boat wanted to steer towards starboard, even though I had adjusted the prop strut to turn towards port based on what happened at the race the previous weekend. There were many patches of floating weed, most of which didn't protrude down more than a couple of inches. Some caught on the bows of the boat and/or stabilizers, but it mostly washed off with the next wave.

My speed to Bainbridge wasn't all that exciting, reaching above 7 mph only on rare occasions and generally in the 6 mph area. I was taking photos at the start and from time to time, so this negatively impacted performance as well.

Upon reaching the buoy at Decatur Reef the camera got into an error state requiring me to unseal its waterproof bag, remove the camera from the bag, extract the battery, reinstall the battery, put the camera back into its bag and reseal it. Of course, this happened just as I encountered the first of the oncoming boats, so I nearly stopped while doing the more critical actions, and then somewhat slowly got things back together between the gaps of racers.

In years past I didn't get quite so far along the course before encountering the fastest racers, so I guess the boat is faster in equivalent conditions.

Upon reaching the Blakely Rock I found the boat ridiculously hard to turn towards starboard. I ended up with the right rudder deployed almost the entire return leg. Also, the waves caused the prop to ventilate quite a bit, approximately every second or third wave.

I think the reason for the rudder issues is the action of the wind on the boat race number, which is a wedge shaped coroplast placard taped to the rear deck, and wind against the dipping rudders. The pressure against both surfaces was causing the boat to turn north. The adjusted prop strut just made things worse for the return leg. Regardless, some drastic work needs to be done to get the steering to work better. It is really frustrating.

The winglets, which are now permanently glassed to the floats, seemed to work well. There were only a couple of times where I am fairly certain they kept me from capsizing. This was when some 2+ foot waves were encountered, and once when something weird happened on the water. There was a moment when something (wave? seal?) sharply pushed up on one side, completely out of the ordinary mess that went on previously and afterwards.

I finished the race with a fairly slow time compared with flatwater Cadence times for the same race, 1:23 or so vs. 1:15 a couple of years ago. Weeds were definitely more of an issue in the Cadence than in this boat. My place in the standings was nothing spectacular, somewhere in the 30's out of a field of 42. Of course, I was doing a lot more than just racing! I had quite a lot of energy remaining after the event, too, but just couldn't seem to apply it during the race. The agitated water and squishiness of the drive system in those conditions just didn't make for good results.

Launching and retrieval at Alki was OK. With the ebb tide I had to paddle (with hands or feet) to get to deeper water and get under way, with the prop bouncing a bit on the sandy bottom. The modified dolly worked quite well for taking the boat off the car top, getting it to the launch site, launching it, getting the boat back on it, wheeling it back to the car and putting the boat back on the roof. The modified dolly actually works better than it did when I used it for the Cadence.

Given the performance of the hull in rougher water I think it could be possible and advantageous to lower the seat bottom by one or two inches. The gearbox and cockpit floor panels could be lowered by the same amount. This would help lower the center of gravity. The fore deck could be lowered somewhat, though I did have a couple of waves that managed to slightly wash over the top.

Strictly speaking, having the seat bottom at or below the waterline would be even better, though this would require the hull to be wider. A venturi tube or drain would be needed if the boat were changed to be a sit-inside, too, but that is a minor detail.

Here are the photos from the race.

A photographer was on Blakely Rock. He took a couple of photos of me, along with the other racers.