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Core Sound 20 Mk 3 -- #4 "Chessie" . .

Pete McCrary

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Attention: NEWS ABOUT "Chessie" - -


For an overnight or two, extra water is needed for cooking, washing, etc.  So, with shelf-space available on the forward locker's top, I fabricated a bed (and hold-down strap) for a standard 2.5 gal water tank with its spigot conveniently over the edge of the locker.



As a solo sailor I often wish for a helmsman to steady Chessie's course into the wind while I  raise/lower sails, anchor, etc.. So, I purchased a Raymarine "Tiller Pilot."  Here's the setup:



Not shown is its stowed position which is along the side of the starboard cockpit coaming with its push-rod resting in a notch installed over the transom.  The tiller pilot is stowed (whenever not in use) by lifting the push-rod off the tiller extension, retracting the push-rod and simply rotating the assemble aft and dropping the retracted push-rod into its knotch.


Also, not shown is the "push-pull" on/off switch installed on the starboard side of the footwell.  The Tiller Pilot has its own fuze protected circuit.  So whenever the main on/off switch is on, the TP is available for use.


Chessie has a new motor: a Honda 4 long-shaft with a 6 amp charger.  The charger was considered necessary because of the considerable electrical requirements of the Tiller Pilot.  Also, the battery charging from occasional use of the motor pretty much substitutes for a solar panel.  The charging circuit is fuze-protected but "unswitched" so that whenever the motor is used -- the battery is being charged even if the main switch if "off."  For shore-side use there is a separate charging connector (on the outside of cabin bulkhead [Blk 3] and weather-protected under the port-side cockpit coaming -- also fuze-protected and unswitched.


Shown here is the happy owner on the first "sea trial" for the OBM.  Also shown is the tach-hour meter installed.  Its display is a liquid chrystal requiring very little energy.  Its input is simply a wire (the end of which is) wrapped around the spark plug lead held in place with a very small cable tie.  Switching between "hours" and "rpm" is by a "toggle" button at lower-right on the module.  Cost < $50.  The tachometer allowed me to discover that the maximum rpm was only about 3900 -- below the rated 4500.  Turns out that the dealer delivered the 4hp with the wrong prop -- a 7-7/8 d x 7-1/2 p.  We replaced that with a 7-7/8 x 5-7/8 prop.  Now she reves up to over 4500, developing a full 4 hp.  Pushes Chessie easily up to 5.5 knots.



Next is Chessie at her slip next to the Chesapeake Bay Maritime Museum.  She was attending the 35th Mid-Atlantic Small Craft Festival.  We had a very nice sail on Friday.  The last photo shows the skipper showing off (Look Ma, no hands) that Chessie balances very nicely and stears herself.


 Notice:: the tiller pilot was NOT ENGAGED.


See youall at the Messabout on Friday.

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One more essential for Chessie: a Masthead Light.  The Coast Guard requires a 135 degree forward facing white light when under way by power at night in addition to the other navigation lights (port-red, starboard-green, aft-white).  This is sometimes called a "steaming" light.  It's supposed to be mounted (something like) at least one meter above the top deck.  Recent rule changes suggested that a 360 degree light (like an anchor light) could be used as a substitute.  Chessie has such a light (removable) that is mounted on the starboard side of the cabin roof at Blk 3.  It can "telescope" to a height of almost 8' clearing well above the dodger and/or a furreled sail.


However, if Chessie motored at night, the 360 degree light would blind the helmsman looking forward.  So, I needed a "steaming" light on the mainmast.  But the only times I've cruised at night was for an early departure (or late arrival) for a crossing -- and I've only needed to do that twice in 10 years of cruising.  So I've designed and fabricated a steaming light that I can keep stowed and mount it on the mainmast only when needed:


The "claws" are 6mm marine ply, the separator & mounting bracket is 12mm marine ply.  The claws flex just enough to firmly clasp the assembly to the 3" diameter mainmast.





This last photo shows the light pushed onto the mast in its transport position.  The assembly will be kept [up and facing forward] in position by a 10-32 machine screw tapped into the aluminum mast just below the height where I'll want the light.  The power cord will be a flexable "roll-up" cord used for household vacuum cleaners.  There's a dedicated 12v power outlet in the anchor well on Blk 1.  The whole thing (light assembly with cord and plug) will be stowed in a canvas bag or cardboard box -- probably in the forward locker between Blks 1 & 2.

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  • 3 months later...

I keep thinking of jobs for "Chessie," even though she's still in the garage.  Spring fever, I guess.


Alan and I have exchanged a few emails and ideas about problem-rollers on our trailers and the damage they suffer from the loads they support.  Less than 3sq" of hard rubber (on three rollers) supports as much as 1,500 lbs of weight.  And much heavier loading when the trailer hits highway bumps!  Alan is considering a loading trough instead of rollers for his CS20.3.


That reminded that the trailer for Tattoo (my CLC PocketShip) used a trough -- and it worked like a charm.  Here are several pixs:



Notice how high she sits on the trailer.



Tattoo had a straight keel/CB and I worried about the load shifting on the trough -- thus the 2x3 cheeks.



When recovering,  Because the trough had to be so high (on the trailer), Tattoo's straight-stem wouldn't easily go over the end of the trough -- so I had this roller to ease the stem over the edge.


The trough was lubricated and that made launching very easy.  I kept the hook on to keep her from sliding off before the trailer was in deep enough water -- then unhooked her.  With a little backward motion and taping of the breaks -- she just slid right off.


So I've decided to replace the rollers with a trough made from a 12' x 2 x 8.  It's not PT.  The Home Depot clerk warned me that if PT it would warp as it dries out.


I stood on the middle (11 ft span).  That 197.6 lbs displaced the center down by 2.875".


Here's the design sketch of the trough x-section.  I don't plan any cheek strakes.



I think the keel will be held firmly in the center half-round (1/2" radius) cut -- which is a good fit for Chessie's 7/8" keel protector covered with a SS 3/4" half oval.



My plan is to mount the trough on blocking that will replace the existing rollers.  I'll firmly attach the ends on blocking at the heights of the replaced rollers.   And I'll install  blocking under the trough at the position of the third roller such as to LIMIT the downward deflection to just 2".


Alan provided me a profile of the keel that I used (on an exaggerated verticle scale) to determine how much the deflection should be UNDER a line pulled between the fore and aft ends of the trough.  Here's a sketch of how I did that.



We think that when loaded, the CS20.3 will easily displace the trough to closely conform it to its own keel -- distributing the load over the entire length of the trough.  Perhaps not evenly -- but certainly without any high concentrations of load.  I think the boat will have a much gentler highway ride.


And launching, and especially recovery, will be easier.  Here's a sketch of the geometry of a typical recovery.


This shows a ramp of 8 degrees of slope.  The trailer has been backed to the point where the water just comes to the hitch ball.  And the boat has been manouvered into position where its keel (just aft of the stem) is touching the trough.  Then the skipper can step from dry ramp surface onto the trailer's running boards -- walk down a "walking" plank with the winch hook and secure it on the bow-eye -- and return to the winch to crank her up the trough.  The angle of the winch cable and the still-floating stern ease the force required.  Or, so I say.  We'll see.


Notice that we souldn't need a roller at any point.  Also note that the trough need not be lubricated except on about its fward two-thirds.

I haven't started the project beyond this phase -- critical comments and suggestions are welcom.


PS -- I'll cut that half-round groove with a 50-some year-old Craftsman molding bit on a 50-year-old Cradtsman table saw.



That all folks.




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Just gotta toss my thoughts in here. Because of roller problems on plywood boats, I decided years ago to carry most of the load on the side bunks rather than keel rollers, I mount the bunks on edge and cut them to match the rocker in the hull. They span several bulkheads so the bunks can't stress or deflect the bottom. Since the hulls float on and off the trailer, there is no need for the weight to be carried on the rollers. I've done this now with several boats, both sail and power. I'm not criticizing the trough idea. It sounds like a good idea. Just offering another way to solve the problem.

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I do not care for Chick’s trailer setup. I also prefer to put the weight of the boat on the keel and use the bunks to keep the boat upright.


The last few days we have been playing musical trailers to get Alan to the EC with Southern Skimmer. I have Carlita on S S’s trailer and she is well setup except that there is too much friction on the rollers to launch and retrieve without dunking the trailer. Marissa’s trailer was about to be setup for the OB20 so we decided to use it for SS just for this trip.


Marissa’s trailer has been used and submerged occasionally for 8 or 9 years and while the frame is sound, we have had to replace about everything else but the hitch and fenders due to rust.


The key to getting the boat to roll of the trailer easily is to add more rollers to lower the load on each roller. Because there are not enough frames across trailers to have enough rollers it is hard to get enough roller on a typical trailer.


With SS sitting on Marissa’s Trailer we needed to raise the aft roller 1/2” to get her right. We did not have any more U bolts and the current roller brackets were welded on and in the way of a bolt on bracket. We started looking for a roller that we could cobble up that was 1” thicker than the standard roller and we would be good to go. We found that 3” PVC was exactly right size. We cut some 3/4” ply bushings and put it all together and it worked. Remember that it has to do 1 trip and the trailer will be converted to the OB20.


This success got us brainstorming and we agreed that maybe we could make up a wood U channel and put a lot of PVC rollers that were positioned to fit the keel rollers. If we need more rollers we can just drill some more holes and add as many rollers as we need to roll smoothly. I based the width on 6” x 3/8” SS bolts and the wood rails are 5/4 - 1” thick actual size. Carlita has the metal strip under the keel which should be fine sitting on PVC rollers.


Here is my first attempt to try out.

PVC rollers 5.jpg

PVC rollers 4.jpg

PVC rollers 3.jpg

PVC rollers 2.jpg

PVC rollers.jpg

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Wow!  That's beautiful.  If Chessie's 2x8 trough has too much friction, I just might have go the multiple-roller route.  The last photo looks like you have the roller heights matching a keel profile -- is that right?


Wouldn't you need to be careful to always have a safety chain or winch hook on the bow eye right up to the point of launch?  The trough on "Tattoo's" trailer had a backward slope of 2 or 3 degrees -- which when added to ramp slope -- made her very easy to slide right off.  I was careful to keep the winch hook on until we were in deep enough water.  The extra slope also made cranking her back up harder -- but I managed it OK.  For Chessie, recovery should be easier because the winch crank has two speeds.

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The idea is to not put the trailer in the water past the tires so the boat has to run free. It is easy to undo the winch after you back the boat down the ramp. If the friction is low it will be easy to winch the boat back up again without dunking the trailer.


Yes the rollers are set to follow the keel rocker. It will be a bit fiddly to get it right but one advantage is that if one or two rollers are at the wrong height, you can just redrill the bolt hole at the correct height an inch from the old hole and you will be good to go.


I intend to install side bunks to guide me when retrieving and to help keeping the boat on the trailer.

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As soon as I finish Catnip I'll rip that 2x8 so it will have the trough x-section that I want.  I'll also put a 60 degree slope on the aft end and (over the last 8" or so) deepen the [trough] sides so as to guide the keel's  3/4" half-oval into the groove (1/2" radius) at the bottom of the trough.  And I'll try launching and recovering Chessie with the trailer backed only down the ramp so that the end of the trough is about 6" under water.  That just might keep the trailer wheel bearings out of the water.  Better yet, (looking at my diagram [posted on 2/16/2019]), I think I'll return the 12 foot 2x8 for a 16 footer -- and make it as long as it can be (and still clear the dip at the end of my driveway).  Maybe I'll even be able to meet Graham's goal of keeping the trailer wheels dry!


I'm considering covering the bottom of the trough with two overlapping (at the centerline -- knitted edges outboard) 10 oz 4" FG tape over the entire length.  And treating the rest of the surface with some kind of penetrating oil.  Maybe something like Tung Oil -- to resist moisture penetration and add a bit of lubrication.  Maybe that'll be enough protection considering that it will be under the boat most of the time and in a garage off-season.  And the surface could be easily retreated from time to time.  Comments, anyone?

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Jay asked about my "Walking Planks."  Chessie is on her trailer in the garage -- so these were about the best pixs that I could get.  The main planks are 2x12 (1.5" x 11.125").  They add some weight to the trailer, mainly on the tongue.  But I find them very useful.  The one on the starboard side is shorter so that the hinged tongue can fold all the way back against the side of the hull.  You can see from the  next photo that the planks don't add any width beyond the fenders.





The planks are high enough so that (while standing on the plank I can reach high enough on the mast to slip the mains'l slides into the sail track.  I can also reach to the bottom of the anchor well.  Also, the forward ends provide a nice place to lay out either sail onto its open "sail bag," sit to change wet socks, or just a place to rest out-of-the sun (unless at high noon pointing south).



Looking aft, this shows the walking plank that runs diagonally from the port-side of forward roller cross-beam back to the midship roller.  When recovering and the boat's bow is near the center roller, I use this plank to walk back with the winch hook and secure it to the bow-eye.  The plank you see to-port is the CB catcher.  When trailering, I ease off the CB pennant so that the CB just touches the plank.  I'm thinking that by doing that I've extended the useful life of the pennant.  If the CB is "bounced" up by a highway jolt, it be stopped with a rubber cushion placed at the top inside the CB housing.



This shows the forward end of that diagonal plank where it is secured to the cross-timber supporting the forward roller.  The lumber is from Home Depot -- but not PT.  And not their Douglas Fir (which is their best quality).  Their clerks are usually helpful in helping me find nice straight pieces.


Hope this helps you visualize the details of the "walking boards>"




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It seems like there are two schools of thought here:  Back the end of the trailer into the water and roll the boat off, or back most of the trailer into the water and float the boat off.  I guess I have defaulted into the second, but maybe I want to be into the first.  I'll have to give it some thought.  I see that others have taken the roll-on/roll-off approach.  Pete, your walking plank seems like a good idea for either approach; thanks for the idea.  I'd missed it before.

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Thanks Pete,  that is one of the “farlkles” I plan for the new trailer.  We usually launch at Keesler AFB and the ramp we use doesn’t have a pier to wrangle the boat from.  Pete Planks should help.


As a side benefit, might help keeping mud and such from being slung on the hull.



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On February 16 I posted some ideas on how possibly to ease loading stress on hard keel-line rubber rollers used to transport, launch, and recover our trailer-sailor boats.  Having good experience with "keel-troughs" for two boats (a CLC PocketShip and a Com-Pac Eclipse), I decided to replace the 3 rollers on "(Chessie's trailer) with a wooden trough milled out of a sixteen foot 2x8.


Today Annie and I rigged up my 50 yr-old Craftsman 10" table saw, a step ladder, and an adjustable support -- and then sprayed dry silicon lub on all sliding surfaces [saw table, ripping guide, step ladder, and remote support].  Five cuts later we had the trough roughed out.  And we both still had all 10 fingers.  Here's what it looks like:


This shows almost the entire 16 feet.  It will be mounted on the trailer with blocking on three cross members -- with the fore & aft supports just 11' apart.  The excess overhang will be trimmed to avoid dragging at the dip at the end of my driveway.



A better view of the centerline one-third-circle trough.



That sharp edge will be softened to reduce loading stress.  Also the surface will be sanded smooth.



This more clearly shows the trough X-section.  I feel fairly confident that the shallow "V" will keep the keel well centered.  To guard against the wood splitting, I will coat the bottom with two (partially overlapping) layers of 4" epoxied FG tape.


I'm open to suggestions as to treatment of the top surface to make it slippery.  But not too much.

I'm saving the rollers just-in-case ??  I'll post the results.



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  • 4 weeks later...

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.



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  • 1 month later...

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.




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  • 2 weeks later...

Although Chessie's maiden voyage was almost two years ago -- she hasn't been sailed much because of OBM problems that were just solved last September with the purchase of a 2019 Honda 4 long shaft.  Now that the OBM is working just fine, I'm looking forward to much more sailing this season.


So, I decided to fine tune the reefing system.  From the sail plans I measured the distances between the cringles (tac to 1st reefing and 1st reefing to 2nd reefing).  Using those distances, I marked the halyard with colored plastic tape.  For each reefing position, the halyard was set first to the measured point -- then the other lines trimmed and positions marked.  With sail's head full-up (no reefs tucked) and other lines trimmed -- I marked each line (just ahead of its cleat) with BLUE plastic tape.  That included the reefing lines with slack taken up and the topping lifts.  I chose BLUE as a reminder that fair sailing is like the "sky's-the-limit."  GREEN for the 1st reefing points and RED for the 2nd reefing.



On the starboard side (left to right): Downhaul (tac cringle), snotter, and halyard.  Trimmed positions for the 2nd reefing.



Port side (left to right): 2nd reefing downhaul (cleated), 1st reefing downhaul (not cleated, and topping lift.  Trimmed positions for the 2nd reefing.  Notice that the 1st reefing line position is the same for both reefing positions.  Also, the topping lift shows BLUE because its trim position is the same for all.



Keeping the lines off the deck.



I changed the cleats on the sprits from the "jam" type, to small "horned" type.  The horns provide purchase for attaching the excess lines when sailing reefed.  They also help keep the reefing lines where they belong when the sail (with the sprit) is stowed in its sail bag.



The red  line (white with red marks) is for the 2nd reefing position marked with RED tape.  The reefing line for the 1st position (white with green marks) is marked with both RED & GREEN tapes because it's the same for both.



Set up with both reefs tucked in.  This is the position for my take-down after recovery on the ramp.  The sails are kept bent to their sprit booms with the leech reefing lines in place.  The sail bags are made to hold both and they are transported in the cockpit.  So, when the sails are bent to their masts -- both reefs are already tucked in.  If it's fair sailing, it's easy to shake out one or both reefs.  And if a reef is called for, it's already tucked in.  I think it will work out ok.

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