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Pete McCrary

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Everything posted by Pete McCrary

  1. Trough DESIGN REFINEMENT: Chessie's first cruise of the season cancelled after 125 mile trailering to the ramp at Long Cove in Rock Hall, Maryland. The marine weather forecast was getting much worse -- and I decided to limit cruise to simply a launch, Honda-4 trial, and recovery. Here's photo of trailer's pre-launch position on the ramp: Wheel hub just above water level. Notice that this ramp is quite a bit steeper than the one at Leesylvania. Launch and recovery went very well, as before. After 125 mile highway trip (some rain and/or wet surfaces), inspection of the empty trailer trough revealed considerable "road debris" in the trough. Mostly gritty stuff that must of been tossed up by tires on wet road surfaces. I wiped it out with a rag and reapplied the paste wood-floor wax. Next time I'll also carry a stiff brush to clear out the trough after each launch. The load-bearing center channel seems to be holding up OK. There was noticed another design problem. When parked (and boat-on-board), the trough collects water. Although I had drilled a "drain hole" near the middle of the trough's length, it was ineffective. Probably because the keel's half oval was covering it. Also, one drain hole would be [fully] effective at only one slope of the parking surface. There should be multiple drain holes spaced at intervals. And I would drill oversized holes -- filled with neat epoxy -- and then [at each position] two off-center drain holes. Maybe the CADesign program could suggest sensible intervals considering the keel's profile.
  2. Yes, she should be a light tow. But I won't do that until I've perfected loading her into Chessie's cockpit. And because the risk of falling into the drink is higher when transferring from mother ship to dinghy -- I also want to have Chessie's reboarding ladder in good working order.
  3. Dave, installing the bumpers was a "bear" of a job. It's nearly impossible to do it solo. Annie would ordinarily help, but her hands just don't have the strength anymore. I lucked out when Silvia (former aerospace engineer from Argentina, now a part-time upholster) came to my shop (to give an estimate for recovering the antique rocker in my shop) -- and admired Catnip on the workbench ready for her bumper. I asked if I could also hire her to assist me installing the bumper. She was essential in getting the job done. We routinely (when our arms would tire stretching the bumper or holding up the heavy drill) switched jobs drilling pilot holes and screwing in the #6 truss head screws (hidden) and finish washers & screws (visible). And using her upholstering skills she covered the exposed ends (on the transom) with leather. At 3" spacing, that was just under 200 screws! It took us almost 4 hours. She wouldn't charge me -- but I insisted that she at least include an amount when she finishes the antique rocker. She probably won't. She clearly enjoyed being part of the project. Annie and I were very happy that she joined us for lunch, out treat.
  4. Over the winter Chessie has been in her part of the garage where the aft end of the cockpit sole was repaired to stop leakage into the bilge. When I originally laid down the sole I applied a meger fillet and no FG tape -- thinking that it didn't need any additional structural support. At first it didn't leak, but with time and temperature expansions & contractions -- the aft edges developed cracks. A better fillet and FG tape probably would have prevented the leaking. So, now Chessie is in the driveway with masts aboard in their "transport" positions. And, this morning, Annie and I "dry-fitted" a "nested" Catnip (a Two-Paw 7) into Chessie's cockpit just ahead of the mizzen mast. It was a "bear" to load each half. Mainly because Annie and I had to lift it up-and-over the guid-on. I'm sure I couldn't have done it solo. But they nest very nicely between the companonionway and the mizzen mast. Showing Chessie loaded with Catnip and both the mizzen and mains'ls in their covers already bent (with their reefing lines) to their respective sprit booms. Catnip's CG is just a little ahead of the trailer axle -- so its 60 lbs will contribute very little additional tongue weight. Although ordinary access to the companionway is blocked, it can still be accessed from the starboard side. With some adjustments, I think that I will be able to load and unload each half into Chessie's cockpit. Note that the 2" ID PVC pipe (guide-on) can be easily removed leaving its [steel] support inplace. The support is much longer than required -- so I'll cut it down to just below the edge of the cockpit coaming. Then I'll fabricate a horizontal support (secured to the shortened guide-on support) -- on which I will be able to lift one edge of a half-dinghy and slide it over the coaming and into the forward cockpit. The same for the second half. That should take care of one problem (for a solo sailor). However, each half is very awarkward to life and carry about. So, I need to design and rig convenient "handles" that can be temporarily attached to each Catnip half. Thirty pounds is not too heavy for this senior, but there must be some way to get good purchase on each half. This Friday Chessie and I will participate in the Spring Cruise hosted by the Shallow Water Sailors. Catnip will not participate, but I hope to have the problem solved before our next cruise scheduled for Memorial Day weekend. SUGGESTIONS WELCOME.
  5. Catnip is finished! Here are a few photos: Later I'll modify the fwd corners so that the rubber part of the bumper is the first to hit something. Notice the deck-plate on the aft port-side flotation tank. She has five oar locks. Two rowing positions and one on the transom. They come in pairs and one was defective. West Marine replaced the bad one (welding lumps on the inside) with A PAIR and didn't want me to return any. So, I ended up with 5 good ones for the cost of two pair. Each half weighted just about 29 lbs (without the oarlocks or removable seats). They would add about 3 more pounds and both oars (together) weight 5.5 lbs. Total all-up weight about 65 lbs (including oars). Next I'll post (on Chessie's build) the results of the "dry fit" of the nested Catnip with Chessie's cockpit.
  6. Just in time -- I'm about to finalize design/fab a reboarding ladder for Chessie (a CS20.3). The problem I see with the Plastimo ladder is common to all rope types: the boarder's CG is directly underneath the point where the ladder is attached to the boat. In order to get aboard, the "swimmer" must have some leverage to move his CG outboard while simultaneously raising his body weight. His leg-strength is mostly useless because that pushes the ladder further under the boat -- so almost the entire [reboarding] effort shifts to his arms and hands, which must have good purchase. The cartoon diagram [shown in the link to Palstimo] of the stick-figure reboarding does not show a realistic position for reboarding. Perhaps it's OK for when the swimmer first approaches the ladder, but once he begins actual reboarding, the stick figure will rotate to almost directly under the transom. Four years ago when I started building Chessie if found the following on the forum (one of Chick's postings). At that early stage (of construction) I installed blocking inside the transom to support whatever I might finally decide for a ladder. I may have posted some ideas on Chessie's build. I kinda remember a cartoon showing a stick-figure trying to reboard. Have a look at my posting on Chessie's bulld dated November 26, 2017: I think an effective reboarding ladder is an important safety issue. Especially for a solo sailor. I hope to finalize a design and fabricate one this season. I'm still open to alternate ideas.
  7. Thanks Jay, for the Liquid Roller tip. I'll try it on the trough as well as the side bunks.
  8. I think you're right. At this early stage my only concern is how well the wood trough holds up to the wear and tear of launch and recoverys. I tried to smooth over the oval-head screws (holding fast the 3/4" half-oval) -- but the job isn't perfect. If need be, I could cover the sliding surface with something like vinal siding -- carbon fiber? Only time will tell. Maybe what I have will do ok. We'll see.
  9. Yes, I had hoped that with the trough setup I'd be able to launch and recover while keeping wheel bearings just above the water. After two launch/recover sessions, I don't think that will be achieved. However, launching and recovering [solo] is definitely easier AND a softer highway ride for the boat and no more damage to rollers.
  10. Dave, a roller wouldn't help. I used to think so and installed one [at the trough end] for my CLC PocketShip. But when I sketched the ramp-trailer-boat geometry I could see that the roller didn't touch the boat's keel until it was almost fully on the trailer. Here's a side-view sketch of my CS20.3 approaching the trailer on a typical ramp. River water surface shown by the blue "wavey" line. The crank effort is not any greater than when I had three rollers. But I suspect that one or more rollers were not "rolling" because of damage. So I was probably just sliding the keel over a roller or two. Towards the end (of the recovery) the crank effort naturally increases more because the radius of the cable shaft [probably] doubles, which would reduce the winch's mechanical advantage by half. But the lower gear can offset that. And, of course, the boat displaces less water as it moves up the trough.
  11. Chessie has been launched again -- and this time the trailer was backed less deep down the ramp. The photo below shows that the keel at the transom was just into the water rather than up to the bottom of the boot. The water level was still just above the wheel bearings. I did the same launch maneuver (drift back a little, then hit the brakes) -- and the boat slid off, but not all the way. To get her all the way off I had to pull quite hard on the mooring lines. But she did slide off. Apparently the stern needs to have a floating component to assist in the launch. Next time I'll back down the ramp so that the water comes up to the bottom of the boot. Ready for the launch maneuver. Cranking her up on recovery was also a bit harder. But the trough keeps her lined up nicely -- making solo recovery much easier than the roller setup.
  12. Ditto what Steve posted. The geometric configuration of an OBM may seem simple, but it isn't. Accurate dimensional drawings are hard to come by. Get the motor and construct a "mock-up" for installation and try out various routines. You're bound to discover limitations and figure out accommodating adjustments.
  13. A few days ago I was able to recruit an onlooker at the ramp to take a video of Chessie's launch. This time I backed the trailer into the river with the water just about an inch below the the WL boot. That put the wheel bearings just under water. Here's what it looks like: This shows position of the rig just prior to the launch video. Next is the video of the actual launch. I just let the pickup and trailer coast backward about a foot, then hit the brakes! That overcame the "slip/stick" effect -- and she slipped smoothly into the river. IMG_1928.mp4 In the pickup I carry a can of Johnson's paste floor wax -- and before recovery give the trough a good swipe. This time the trailer wasn't so deep into the river [than the first time] which caused a little harder cranking on the winch. The last foot or so I shifted to the low gear. The winch hook was attached from the dock and the boat nudged onto the end of the trough. Once in the right place the tug of the winch cable kept her "lined-up." Shown here after recovery. I consider the modification a significant improvement for both launch and recovery -- AND a much gentler highway ride for the boat. Probably less trailer maintenance as well. Next time I'll see how it worke if I back only so far as to keep the wheel bearing dry.
  14. Nice work Amos. You'll find the shelving very useful. For builders who haven't installed the sheer strakes -- it's much easier to install the shelf-supporting cleats before doing the s-strakes. Same for any drawers you may want that may be stowed between Blks 4 & 5 that [for easy access] slide out over the bunks. For Chessie I'm still trying to figure out where to put hangers for shirts, hats, jackets, etc.
  15. "Skeena" really looks nice. Hope to see her in October. I like the name and history of the nice kitten. We have two cats -- half sisters from a farm. Same mother, different Toms years apart. The oldest (14 yrs & all black) is very "skitish," and a third the size of the younger (6 yrs & orange). Our 4 kids and 11 grandchildren have never seen the older one. -- but she's very affectionate with me. But the young orange one pals up even to strangers.
  16. Thanks for the suggestion Mike -- but I couldn't make it work. However Frank Hagan got into the "codes" and all is well.
  17. Yesterday, April 1, was the launch test -- abbreviated. The trough worked just fine for launch and recovery. Much better than the three rollers that I was using. Here's how it went. Hampered by a very low tide and shallow ramp caused by three days of strong winds pushing water out the Potomac. I wanted to be into the water as little as possible -- but I was worried that the sliding boat might "plow" into the concrete ramp (just about 15" where the boat would plunge into the water off of the trough). The above photos show where I wanted (but didn't) launch. The tires were in the water, but the wheel hubs just above. So, I backed down a little deeper. Later in the season, I'll try a shallower launch. Wheels under, but not the fenders. Boat not yet floating. Next I unhooked the safety chain and the bow eye, drifted back a few inches and "tapped" the brakes. Chessie just smoothly slid into the water -- pretty-as-you-please. Shown above she floating but secured by her bow eye ready for recovery. Notice the yellow stripe on the dock -- that marks the end of the concrete ramp. You can see that the trailer wheels are not far from it. Recovery was easy, single-handed. Nudging boat's keel onto the trough (above photo) -- I took the winch cable and hook onto the walking-boards and secured it to the bow eye -- then (using the "high-gear" on the two-speed winch crank) she was easily pulled full-up onto the trailer. The effort was much easier than that required to recover over the rollers, where near the end I'd have to switch to the low gear. I think the damaged rollers weren't "rolling." She's part-way up. I think this is the full-up position at recovery. At launch the mooring lines would have been cleated to the dock. She's full-up and secure. Next time I'll try launching (and maybe recovery) with the trailer backed down the ramp just so the wheel hubs are dry. So far I feel pretty sure the wooden trough approach is much superior than the rollers. And simpler! KISS.
  18. The original trailer for Chessie (a Core Sound 20 Mk 3) carried her (1" yellow pine keel w/SS half-oval) on three hard-rubber rollers. The side bunks were adjusted to carry loads just enough to keep her balanced at the verticle. That arrangement concentrated her load on just three places and, over many miles at highway speeds, the stresses caused by potholes, RR Xings, unseen speed "humps," etc., -- caused the rollers to be severely damaged at their centers (the only load-bearing part). Note that there has been no noticeable damage to the keel. The chipped-away rubber pieces made the roller no longer cylindrical to the point that they often didn't "roll" at all -- causing launching and retrieval problems. I learned that Graham had similar problems and was considering a trough with many rollers. That reminded me that I had used flat platforms to carry my CLC PocketShip and a Com-Pac Eclipse (both had, respectively, wide ~2" & ~4" flat keels). So, maybe the concept would work for a CS20.3 and other boats without flat keels. So, here's what I came up with. This shows the rip-cuts made on a 16' X 2 X 8 straight piece from Home Depot. The bottom of the board was covered with two epoxy saturated and overlapping (only by an inch at the center) 4 inch X 10 ounce FG tapes over the entire length. The top and sides were covered with three coats of neat epoxy -- and the top with a final coat of neat epoxy mixed with powered graphite. For Chessie's trailer I trimmed the 16' trough down to just 14 feet. The "rough cut" cross section. The sharp edge of the half-round centerline trough was rounded over with a smooth plane. The 4 coats of neat epoxy tended to collect (at bit) at the bottom of the half round -- which was desired, as it would carry the concentration of stress and sliding fiction. BTW, the half round SS screws (thru the keel's SS half oval) were "smoothed" over. I measured the height of each roller (above) their wooden mounts and planned to mount the trough such that it's bottom would duplicate the position of the [three] rollers being replaced. Alan provided me with offsets (from the waterline) of the keel at the three points where the rollers were mounted on the trailer. From this I determined that the mid support (under the trough) should be ~ 1 and 15/32" lower than a straight line from the forward mount to the aft mount. Trough lined up on the trailer centerline. Forward support with spacers. Notice X-beam doubler (new wood) under. View from port side slightly aft. Middle support. Trough is not loaded. Now the trough is artificially loaded with clamps. When the boat was lowered onto the trough, there was ~1/2" space -- into which was placed a spacer. Aft support. Shallow-V guides to help guide the keel into the trough. Note that the CB catcher is raised so that the CB won't hang up on the X-beam. The centerline of the trough was further lubricated with paste floor wax. Next I'll report the proof-of-concept trial launch and recovery.
  19. Well Chessie's dinghy, "Catnip" (a Two Paw 7), is finished (except for painting her interior a "battleship" gray). So I'm finishing the conversion of Chessie's trailer from 3-rollers to one 16' trough. Today applied the last coat of epoxy with one tablespoon of powered graphite. Here's a photo: Once the cure was at the "thin-film set" stage -- can you believe that I was allowed to move the sixteen foot epoxied 2x4 board into our living room to cure in 70 degree comfort? Now that's a wife you can live with for 60 years (come July)! I'll smooth out that groove with 400 grit aluminum oxid paper. Once installed, I'll help it be nice and slippery with some paste wood-floor wax. The loading will be reduced from ~500 lbs/roller to just ~100 lbs/foot, or only about 8 lbs/inch! I think the keel will be much relieved and the boat will have an easier highway transport. Chessie is in a lift at Backyard Boats in Woodbridge so that I can have the trailer at home for the modifications. Too much sunshine! Better pix later. Forward roller (aft to right). Middle roller. Note "walking board" going forward (to left). Very useful (recovering) for attaching winch hook to bow-eye and keeping dry. Aft roller. The board at the bottom of pix is the CB catcher. This keeps the CB from ever dragging on the highway -- and also never hanging up on the aft cross member when launching. Once the new trough proves itself in a trial launch -- I'll discard the rollers.
  20. My DN iceboat (sail #2141) could definitely make way downwind faster than the wind -- but not directly downwind. To do that we had to tac (jibe?) -- during which we had the [apparent wind in our faces]. Here's a link to a wind-powered machine that goes much faster directly downwind than the wind: https://www.google.com/search?q=going+downwind+faster+than+the+wind&oq=going+downwind+fas&aqs=chrome.1.69i57j33l3.38470j0j4&client=ms-android-verizon&sourceid=chrome-mobile&ie=UTF-8#imgrc=_ An iceboat sail performs just like a propeller blade with a very large radius. The skipper of an ice boat is always pulling hard on the sheet (usually with x6 purchase) on any heading mainly to flatten the sail which improves its L/D ratio.
  21. The "polar plot" shown previously is not for a "water" boat, but for an idealized iceboat (steel on ice friction & windage, both) = zero). The plot is with respect to a wind-speed of unity. A water Catamaran would have a polar plot looking something like this: And it would look different for various wind and wave conditions. Years ago I had an Auqua Cat with an A-frame rig holding up a lanteen loose-footed sail. On smooth water in a good wind it made better progress downwind by tacking as opposed to going directly downwind.
  22. Reacher: What you need is a polar plot of your boat's performance on all points. For a boat with zero friction at the "interface" (which an iceboat approaches because steel on ice friction is very very low) -- the polar plot approximates a circle. It looks like this: The vector W is the wind velocity and V is the boat velocity (showing speed and direction with respect to the wind vector -- which is straight up the page). The circles represent the boat's performance expressed as a function of its heading and the L/D (lift to drag) ratio of its sail (ignoring the boat's windage). So, an iceboat with a sail having an L/D of 3 (typical) or 5 (high performance) can, on a broad reach make V = 3 X W (typical) or V = 5 X W (high performance). Note that directly downwind the polar plot shows that V = W no matter what the L/D is. The horozontal L/D of a keel-less boat is quite poor, but is vastly improved by a centerboard, especially one with a hydrofoil with high aspect ratio (length to width). For steel on very smooth ice, the "L/D" is probably close to the inverse of its coefficient of friction. The velocity polar plot is affected by these performance figures (in each medium) for the vehicle traveling in this "ancient" interface -- water/air for boats, hard sand or Tarmac for land yachts, Gravity/air for airplanes, air/string/anchor or surfboard (gravity) for kites. Note that iceboats always sail "close hauled" even when on a broad reach -- and, because they are going much faster than the wind, the sail luffs and a gibe is quite tame. The polar plot shown above was in an article that I wrote back in 1974: I don't know the link, but the article is available on the Internet If you had a compass, a good GPS plotter, a steady wind, and a lake with no tide or current, you could easily create your own polar plot and determine the best point to sail in order to fetch any destination in minimum time.
  23. Green also goes nicely with buff tan -- remember the Jaguar sports car with a buff tan canvas top and British racing green body?
  24. Green bottom. Next the white topsides, then gray interior. Maybe I'll make the aft seat green too. A pair of oars ordered today. Getting there -- six more days of painting.
  25. And when I started my law practice in 1977 my secretary and I had to use an IBM typewriter and carbon paper because I couldn't afford a Xerox copier for the office. It was like the dark ages. On the other hand, I wonder how historians (a hundred years from now) will be able to root out true history? Where will they find and authenticate uncorrupted ones & zeros (recorded as invisible electrons, micro magnets, photons, etc). Won't the number of ones & zeros approach or exceed the total of all protons, electrons, neutrons, etc in the universe? I'm glad I won't be my problem.
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