Tech Tip B01,
((2023-10-13) Bob Schimmel, Paul Bailey, Mike Hancock, Mark Ludlow,
Randy Cook, Bill Ward, John Cowing, Jocelyn Chagon, Robert Hasegawa.
Centerboard, Repair & Modifications
Pivot Hole & Pin,
Raise the Boat - (Jacks/Trailer, Scaffolding, Floor Jack, Gantry Crane, Careen).
year after I
bought Panache, I noticed the centerboard would vibrate
occasionally. The noise was more annoying than it was a concern, but
the advice of several SJ23 club members who said it
could seize in any position I decided to repair it. Being new to a San Juan 23 I
heeded their advice. After my board
removal and repair I discovered that a seizure is
associated with marine growth inside the slot and/or corrosion,
not vibration, so I had quite a different problem. My
experience with a seized board is through other sailors. However,
there is commonality in mechanics. So .......
The factory centerboard is galvanized steel plate. The galvanized coating wears away over time after which the bare steel starts to corrode, swelling and flaking in the process. The oxidation will continue inside the trunk and the board will get tight as the rust associated swelling continues. This is a likely scenario for a boat ignored in a slip. For this reason timely maintenance to the centerboard and its SS lift cable are important. DO NOT let either of them deteriorate to the point of becoming a major problem, especially if you float the boat where the water tends to turn hard in the winter! This is a difficult enough repair without being forced to invent some dangerous technique in the urgency of the moment. Some people remove the centerboard annually to clean the keel slot and inspect the lift cable. This may be a good practice in salt water. My experience in fresh water is to inspect the cable for fatigue once every few years. I have experienced no corrosion. I suggest you check your assembly before it slips down to Davy Jones's locker or you can't retrieve the hull on a ramp. TOP
CENTERBOARD CONSTRUCTION - The factory centerboard is made of 3/8" thick mild steel that was hot-dip galvanized by Ace Galvanizing in South Park, Washington. The 60 lb steel board pivots on a 1/2" diameter SS pin welded to the side of the SS stirrup. The board and stirrup are housed inside a ~1/2" wide keel slot. The pivot pin extends across the keel slot, snubbing against the opposite face, thereby holding the centerboard captive within the slot. The 3/8" thick centerboard is slightly thinner than the ~1/2" keel slot, leaving about 1/16" gap on either side for minimal slop. The board is raised by a 1/8" halyard grade (7x19) SS lift cable that must be replaced on a regular basis. More on this below.
NOTE - The centerboard is fully enclosed inside the keel slot when it is raised to the top and is when it is safe to rest the shoal draft keel on the bottom without damaging the board. This is one of the reasons why I moor Panache with the board up, just in case she breaks free of her mooring. The other reason is the board potentially swinging up, puncturing the top of the keel slot. The trailing edge is sharp so this is easy to understand. I have only heard about this potential in discussions on mooring techniques in very rough water. I have never heard of it happening. However, I have seen what happens when the lift cable of a ballasted swing keel breaks. The board swings down, cracks the leading edge of the slot and the boat sinks. Its a good thing the boat in question had floatation. I wouldn't even this to happen to an SJ23!
PIN & HOLE - After removing Panache's centerboard (2002) I realized I didn't have the seizure problem others experienced but
I was surprised at the 1" diameter hole over the 1/2" OD pivot pin and
considered this to be the source of the vibration.
Hint - Just in case your yard charges by the hour, it is wise to contact an alloy welder prior to removing the board. This way he can be ready to repair/replace the pivot pin if it proves necessary. It would actually be a good idea to install a larger diameter pin. Similarly, find a retail source of bushings if you decide to use my technique to repair a worn hole.
STIRRUP - The SS stirrup has a flange that protrudes out of the keel slot and wraps around the bottom of the shoal keel, to starboard. Here two SS lag bolts (5/16 x 2.25)" with a 7/16" head, fasten the flange to the bottom of the keel. The cutaway profile at right is looking forward through the keel. The stirrup has 5 mounting holes that line up with the 2 holes in the keel. To balance the center of lateral resistance, slide the stirrup fore or aft till a new set of holes line up, then screw the bolts in. Remember which 2 flange holes are used on your boat so you can restore the balance. The factory used holes 2 & 4, counting from the front.
Once you remove the lag bolts, the entire assembly is free to drop out
of the keel slot and the centerboard will separate from the stirrup. The board
weighs 60 pounds
so it is not that difficult to support. If the board or stirrup doesn't release from
the keel slot, you may have to pass a sharp hacksaw blade (or use a
Sawzall with a round tip blade) through whatever
crud there is in the slot. After that, give
the support plate a sharp rap (fore or aft)
with a five pound sledge hammer and a length of flat bar or a flat ended
punch. Be careful when "budging" it with a pry bar as this may
crack the gel coat. A combination of these techniques should break
the grip. To protect against that unexpected drop, leave about 3"
of slack in the lift cable to keep the board from falling on your lap. Things go easier and quicker if you have an
assistant inside the boat controlling the lift cable for you.
REMOVE STIRRUP in WATER - It may be possible to remove the stirrup and centerboard while the boat is floating if the 2.25" lag bolts 'bottom out' in solid material. That being the case it shouldn't spring a leak, but I can't guarantee that. The lag bolt drill hole was measured at 2.5" deep and was solid at the bottom on one SJ23. I never made this measurement on Panache so can't confirm this. But even then, depending on the vintage of the hull, the ballast is poured (early) or placed (later).
There may be all kinds of reasons why you would want to remove the stirrup in the water, none of which I will list here! The major problem is how to hold on to the board and stirrup once they come loose. For this reason I suggest you do this in clear shallow water with a sandy bottom so you have a fighting chance to find the parts. Once removed, I suggest you immediately plug each hole with a tapered rubber plug or flat neoprene and stainless steel washer pressed against the gel coat using the original lag bolt. Don't cross thread the bolt. Either technique allows for a means to seal it underwater or slow water ingress.
Installing the stirrup underwater is NOT recommended because water is the bane of all adhesives. Only mussels and barnacles have solved the problem and nobody yet knows how they do it. Sikaflex cannot stick to a wet surface. A Sikkens technical rep confirmed that to me. Butyl rubber won't stick either. However Tremco Gutter Seal can stick under water as is used to seal an eavestrough. Just hold the tip of the caulking gun against the gel coat and squeeze the trigger to force it to stick. It can be applied to circle seal a bolt hole with a temporary flat plate on top or it can be injected directly into the hole for sealing by a lag bolt. Be careful with this stuff, it can be messy. It will stick to your skin and everywhere you touch it, even under water. Keep some rags handy under water for cleaning. If you can't find Tremco Gutter Seal, you could temporarily fill the void between the plate and keel with a 1/8" thick layer of closed celled neoprene (wet suit material). Scrub the fibreglass nappy clean with a Scotch bright pad before installing the plate. Each lag bolt head could be sealed with flat neoprene washer backed up with a large flat stainless steel washer. (Some of the neoprene should stick out past the washer). The neoprene washer would have to fit very snug around the shank of the 5/16" bolt in order to seal the hole. I suggest smearing a high quality goop over the washer and shank before you take it underwater to fasten the plate. This could give you a fighting chance to seal the hole. If the bolt is a bit loose in the fibreglass (take note of this when removing the bolt) wrap it with several turns of Teflon tape. This temporary fix can be made permanent after the boat is back on dry land when the fibreglass is clean and dry! If you try this technique please let me know if it is successful.
CONCLUSIONS - After installing a bushing on my centerboard, it swings freely and no longer vibrates against the sides of the keel slot. Since 1998, I've experienced no binding and the board is still quiet.
The most difficult part of removing the centerboard is to raise the boat off the trailer, especially on your own. It would require three 6 ton floor jacks, stable enough to raise the trailer and boat about 6".
Each of these options require a lot of preparation but if you don't have access to a crane or a pit then you have to be creative. I researched long and hard till I found a safe method to raise Panache on her EZ Loader trailer since she was already stored in the bush for the winter and moving was impossible due to deep snow around the boat. The steps below list the process I developed to raise the boat using the trailer to "rock" the boat up, one end at a time. The trailer had single axle back then. After all, the trailer frame is strong and the bunk boards provide perfect support, so why not use them. Of course the method had to be foolproof, without fear of toppling Panache on her side and crushing me in the process. The ground was frozen at the time so little fear of a collapse.
SAFETY FIRST - Choose a work location where the GROUND IS DRY, FIRM AND LEVEL TO PREVENT THE WOOD CRIBS FROM SLIDING OR SINKING. You will have to work under a 3000 lb. hull resting on a 1000 lb. trailer. Snug up the trailer winch line at the bow to prevent the boat from sliding backwards off the trailer. Snug up the web straps around the trailer and hull to steady the hull on the trailer. Test the load for steadiness before you crawl under it. This load can easily kill you.
made four 2' high (2x4)" wood cribs to support the jacked up trailer frame. You can
see a wood crib
under the front of the trailer in
Tip A01. Each crib is 1.5' square and fastened at
the corners with 3" spikes. It takes a surprising amount of lumber and spikes to
make one crib. While it is OK to use old (2x4)s, make sure the wood is
structurally sound and the joints tight. Secure a line or metal band around each crib (top to bottom) to hold the
This is a photo from Robert lifting Wild Tangent in 2023 using the steps 1-9 above. I didn't take photos when I jacked up Panache so I'm grateful for this one.
"Ever since I bought Wild Tangent (previously named Aerial), I fretted about the condition of the centerboard, stirrup, and cable. Every time I raised or lowered the center board, I pictured the eye strap breaking or pulling out and being SOL.
To remove the board I put my EZ Loader trailer up on 5 blocks, removed the wheels, and dropped the axle by removing the front pin of the leaf springs. I also had to remove the cross bar that supports the keel in front of the axle.
Because of the maintenance I did on the trailer last year there were no seized nuts. The entire lift process took about 40 minutes. Wild Tangent is now rock solid and safe to work under as you can see in the photo at right. The axle hubs were removed as well since I'm replacing them. The centerboard dropped out no problem. I'm going to leave the boat there for winter, lowering one pair of bunks at a time to repaint with an ablative bottom paint.
Anyway, what made me think of this was the comment in this Tech Tip that you only need about 6" to remove the board. So once again, the web site saved me from a bunch of hassles trying to lift the boat off the trailer." Robert Hasegawa
very secure method of raising the boat is to build an overhead hoist as Paul
Bailey did in 2000 for Mellow Yellow.
1 below). He used scaffolding to support two overhead
(4x4)" beams to lift the hull off the trailer with four Come-a-Longs. This
is an excellent alternative to a crane or overhead hoist. It is
inexpensive, strong, very stable and you have unobstructed access to most
any part of the hull. Compression bars are not required but you must tie
the tops of the scaffolding together to solidify the structure. It
should be noted that Paul took all the necessary safety precautions by
working on hard, level ground and maintained some tension on the belly
slings while the hull was on the blocks. This helps to prevent a collapse.
No sense getting a "headache" while you're working under her. By the
way, each Come-a-Long has
to hold about 850 pounds, less if you empty the boat. Below is the
sequence of his repair work.
| WOOD CROSS BEAMS - John used an automotive floor jack to lift the trailer and boat approximately 8-16", one end at a time, then placed cinder blocks under the trailer for support. Jack up the rear first, placing two blocks on each side and blocking the trailer wheels so it cannot roll. Then jack up the front and place two blocks under the trailer. Then back to the rear and front till the boat is high enough to slip the stands under. Lastly he lowered the trailer away from the hull, leaving the boat supported as you see at right. John prebuilt his wood frames wide enough to roll the trailer out once the hull is supported. You should add padding to the forms
to distribute the load and
prevent the hull from sliding or rolling. Removing the trailer allows clear access to the center board.
If you are going to support the hull on the wood beams for any length of time it is a good idea to support the keel to take the keel strain off the hull. That's what the three cinder blocks in the photo do.
John's support frames at right have (2x6s)" for horizontal beams and (4x4)" posts in compression. All wood is glued and screwed together. You can't be too careful when constructing these. John Cowing
This suggestion comes from a friend who bought a portable gantry crane from Wallace Cranes. The portable Tri-Adjustable Aluminum crane that Jocelyn has can lift up to 3 tons. Lift up one end of the hull and block it. Then lift the other end and block it as well. It might be wise to leave the crane in place. All made in the USA of top quality material.
Confirm the crane dimensions so it fits and SJ23.
CAREENING - Lastly there is one other method. Careen the hull in a slip
sufficiently far enough to expose the top of the keel stub to the water line. Pull the
hull over using the halyards looped around the mast where the shrouds are attached. Also, tie some lines at the bow and
stern to keep the boat from turning in the slip. Then place a ladder on the lake bottom, leaning against the dock finger. Now you can climb down to the keel with tools in hand to replace the lift cable or remove the centerboard. Be real careful with this technique and careen the
hull with no other boats around. If your halyards let go, the mast
will swing well past vertical and smash into the adjacent rigging. In
addition, the hull could pin you against the dock as it rolls. There goes a perfectly good pair of swim trunks! You
wouldn't want that! On the other hand, this is a quick, slick way of getting the job done. TOP
board is hot-dip galvanized steel coated with a black shiny finish. I
don't know what the black coating was but it seems pretty good at repelling marine
growth. If you wish to
restore the finish to something similar, sandblast it, etch it with acid,
then coat it with WEST
system epoxy thickened with carbon graphite powder. The carbon graphite makes the
durable and slippery. It does not scratch over granite
rocks for instance and it just might be too slippery for marine
growth, especially if you retract the board inside the dark keel slot when
the boat is in her slip. Panache's rudder blade is coated with this
'chemical cocktail' and it does wonders for smooth flow. Some people
have suggested adding some foil shape to the board to improve the hydrodynamic
flow. But it can't exceed 1/2" thickness which is the with of
the keel slot! It is doubtful that foil shape within these dimensions will improve performance.
This effort will likely boost your ego more than improve
the performance of the board since the flow over a flat board is all screwed
Making this board slippery is probably the best thing you can do for hull
reassemble the centerboard support plate, circle seal the lag
bolt holes with Sikaflex or butyl rubber and smear a thin coat between the mounting flange of the support plate and the
keel. Circle seal the under side of the bolt heads and tighten them to just snug, leaving some squish room
for the sealant when it has cured. Fight the urge to over tighten them or
you will strip the thread in the fibreglass. Then you will have to
do a fibreglass repair job as well. The hardened sealant will keep the water out and lock the bolts in place. Have faith, they won't drop to the bottom of the
Sometimes a centerboard is so pitted from salt water corrosion that it must be replaced. Several people have wondered about fabricating their own board from 304 or 316 stainless steel. The thought being that a SJ23 centerboard will occasionally scrape on a reef, sand bar or beach, and the extra cost of stainless steel may be rewarded by near indestructibility. Mark Ludlow has sailed his SJ23, "la Loca", with a 1/2" thick stainless board since 2005. While he didn't take any photos, the board looked like new when he hauled the boat in 2015. He sailed at the mouth of the Columbia River. What follows are his and my thoughts to answer questions from various sailors. Mark works as a chemical process and design engineer, dealing with corrosion all the time. I was tier 3 technical support for the local telephone company where I was often confronted with galvanic corrosion to solve a communication problem.
"So, all in all, I stand by my recommendation demonstrated by years of successful operation under difficult corrosive conditions of using 300-Series stainless steel for a centerboard. This being said, I wish to re-emphasize the need to smoothly chamfer the edge-drilled hole where the cable leaves the centerboard. I re-rigged the standing rigging on my boat with 5/32" cable so I used it here as well. But as I mentioned, I have always sailed with the centerboard all the way down, (although I suspect that's why "la Loca" has so much weather helm). If the board were hauled back to 700, there would be a constant strain on the cable and a smooth chamfer would be required to prevent wear. It's easy to chamfer the hole with a grinding stone or a carbide burr in a grinder (electric drill at a slower pace).
"I replaced my factory original steel centerboard with ½” stainless steel that I fabricated around 2005. To attach the lift cable I cross-drilled a hole near the up-haul edge and then drilled an intersecting hole (slot in picture) from the edge into the cross hole. All surfaces were ground smooth, including chamfering the edge of the drilled intersecting hole that is most likely to abrade the cable. For the lift cable I used flexible 5/32” stainless steel halyard cable and crimped a “ball” on the end that fits comfortably in the cross hole. This method of attaching the lift cable is similar to a brake cable on a mountain bike. A barrel would create better support than a ball but it would be difficult to fit into the hole.
Initially I tried poly line with a single loop through the centerboard hole but the keel slot is quite narrow and anything that is much wider than the centerboard causes interference in the motion of the centerboard. The solution I used works flawlessly and the whole project, with stainless steel at 2005 prices, cost under $150. This is less costly than just the galvanized centerboard in the SJ23 parts list." Mark Ludlow
CONCLUSION - The best material for a centerboard is 300 series stainless steel. The next best is to coat a mild steel board with epoxy and carbon graphite powder, pivoting it over a bronze bushing. The latter is about as optimum as you can get, considering cost and corrosion free operation. By the way, the extra thickness will make the boat a tad stiffer which is always nice.
However, if you've stubbed your toes on that sheet of 1/2" thick stainless steel
laying in the garage,
you should definitely
try it. Judging by Mark's experience you have nothing to loose and
everything to gain. But if you don't want to lay out your beer money for
a new stainless steel board I would seriously consider coating the existing
steel board with epoxy and carbon graphite powder. The slipperier
the better. For an aging sailor who doesn't have that many years
left, it would be a cost effective solution! Elbow grease has its rewards!
The factory centerboard lift system consists of a heavy duty eye strap screwed to the cabin floor at the base of the table pedestal, a 3x1 block and tackle shackled between the floor eye strap and the 48" long 1/8" SS lift cable that goes over a sheave at the top of the table pedestal. It then goes down the pedestal to an eye strap screwed to the aft edge of the centerboard. At no time does the cable rub on fibreglass inside the pedestal.
The 1/8" lift cable is made from (7X7) flexible halyard grade SS cable to survive the flex and stress over the sheave. An eye with thimble is swaged to each end of the cable (best to use a copper swage instead of aluminum). You could make it easier on yourself by swaging the board end first, then pulling the line over the top sheave to swage it to length at the block & tackle on the cabin sole.
The lift cable eye is fitted directly to the eye strap screwed to the aft edge of the board by two 10x24 3/4" SS machine screws spaced 1.5" apart. While a #2 Roberts screw (red handle screwdriver) is factory standard, the screws on Panache were slot drive, so be prepared for anything! If the thread stays clean they will be replaced with Roberts screws next time since they are the easiest to twist underwater without stripping the head.
The majority of lift cables break by being stressed over a misaligned sheave at the top of the pedestal. The first symptom to show is a meat hook on the cable so be wary of this. I've also heard of a thimble that broke in the middle where it rubbed against the inside of the eye strap on the board. The pull on the lift cable is approximately 100-150 pounds with the 60 pound board pulled up inside the keel slot.
Assemble the replacement cable exactly the same way as the factory cable. The cable eye installs directly through the centerboard eye strap. Therefore the eye rests across the keel slot. Since the keel slot is just a smidgen over 1/2" wide, you MUST swage the 1/8" cable over a 1/2" thimble (factory size) so it can fit inside the slot with the board fully retracted as required for the trailer.
The factory specification calls for the SS cable to be 48" long, measured from the end of one loop to the end of the other, using a single Nicopress sleeve at each end. If you want to double swage the cable cut it 50" long to allow for the extra crimp, thereby maintaining 48" overall. Failure to do so will prevent the board from being lowered to the designed operating angle. You could make the cable 51" long, making it possible for the board to hang vertical, but don't make it longer than 51" as you will not be able to pull the board up fully with the block and tackle. The board must be fully retracted inside the keel slot and locked there for trailer launching. The normal sailing angle for the board is about 700 (aft) but I know of several sailors who sail their boat with the board closer to vertical. If you want to lower the board to the correct sailing angle every time, tie a knot in the block and tackle line to limit the travel. I like this technique as it is "idiot proof" during times of urgency or for commands given to a green horn!
NOTE: The centerboard eye is exposed about 3" below the keel stub when the board hangs vertical. Therefore, it is possible to replace the single ended cable with the boat floating! Look at the photo at right and notice the location of the eye strap exposed just below the stub keel. (Left side of board). Best to do this job with the boat in 5' deep water, over a hard or sandy bottom so you don't kick up silt to block your vision. Wear a weight belt for good footing on the bottom. At least this part of the job is convenient!
To access the centerboard you have three choices;
CAREEN A BOAT -
"The hull can be careened 400 in a slip by pulling the main and a jib
halyard from the mast head. Wrap the halyards once around the mast where the shrouds attach to transfer the strain to the mast. Stand a long aluminum ladder on the bottom, leaning against the
dock. Climb down the ladder to
get within arm length of the board. You may have to stand in waist deep
water to do this but it sure beats diving under the hull. You could also careen the hull
in 4-5' deep water in
which case you will be standing on the bottom. You determine which technique is easiest for
you." Gene Gardner.
Assuming you will replace the SS lift cable with the boat floating, remove the table to open the top of the pedestal and lower the board to vertical. Attach a light line to the top end of the new cable (so you don't loose it) and lower the new cable down the pedestal till it exits the keel slot at the bottom. From this point you can choose to dive under the boat or careen the hull and reach into the water to replace the cable. Feel for the eye strap just below the keel. Remove one screw of the eye strap and slightly loosen the other. Be prepared to really torque on each screw as they will likely be corroded. You might have to use Vice-grips in conjunction with the screw driver. Rotate the eye strap to the side a bit, remove the old SS cable and slip the eye of the new SS cable under it. Realign the eye strap to the screw hole, and drive the screws home. It seems prudent to apply some water proof anti-seize thread compound to each screw before you tighten them. After all, why not make life easier for the next time. Pull out the old cable and test the operation by raising and lowering the board several times.
KEEP THE LIFT CABLE OVER
THE SHEAVE - In 2004 I mindlessly drifted
over a sand bar that stopped Panache dead when the centerboard slid over the
bottom, pushing the
slack lift cable up off the sheave. This wasn't a big deal since all I needed to do was lift the board and
keep going, or so I thought. Back in deep water I had a bigger problem when I
discovered the lift cable had jumped off the metal sheave to lay over the bolt
the sheave turns on. It was now jammed solidly between the sheave
and the fibreglass pedestal. Why didn't Clark install a
keeper over this block to contain the cable? On the other hand, why
didn't I watch where I was going? Anyway, I tied a line
around the hull to lift the board after which it took a lot of
picking to pry that cable out. I wasn't about to repeat that
fiasco so fabricated an aluminum keeper over the sheave as shown here.
It also nicely centered the block to keep it from rubbing against the
fibreglass. The cable was replaced 2 years later as it was damaged in the process.
The following are the main reasons why some sailors have switched to 1/4" Dacron or Dyneema line:
SINGLE ENDED POLYESTER LIFT LINE - Attaching a single ended line to the centerboard is easy and neat if you splice a 2" loop in the end and "choke" it off to the eye strap. Stuff the loop half way through the eye, pull the free end of the line through the loop, pull the line tight around the eye and pull the free end up the pedestal with a fish tape or push it up with a stick and you are done.
Another way to attach a single ended line is to tie a bowline and whip the butt end to itself to eliminate a potential snag. If you don't have waxed lacing twine for whipping then dental floss works pretty well. The mint stuff tastes good! Keep in mind that the completed knot MUST be narrower than the 1/2" wide keel slot it has to slide into.
You could make it easier on yourself by attaching the board end first and then pulling the line over the sheave to tie it to length at the block & tackle on the cabin sole.
This line should be inspected annually and replaced about every other season since the bottom 1.5' is always under water inside the pedestal. Replacing the line more often than the SS cable is probably the biggest disadvantage, but it is easy and cheaper to do. Use the old line to pull a new one up the pedestal, provided you had the forethought to replace the old line before it broke! For all the other excuses, you can push a fish tape down the pedestal to pull the new line up! However, you still have to go under the hull to attach the line, hence the double ended lift line.
DOUBLE ENDED POLYESTER LIFT LINE - Here are two great ideas to improve the single ended SS cable system with a double ended polyester or Dyneema lift line. It is dead simple to replace the line using one of the following techniques without lifting or careening the hull.
PS: If this is the first time to replace the steel cable, you still have to dive under the boat to open the eye strap and remove the steel cable. Sorry! Now you just have to decide which of the two techniques above is best suited to you.
Just so you know, the eye strap is positioned low enough on the aft edge of the board for sufficient mechanical advantage to raise it and high enough for minimal drag through the water. See Tech Tip B32. However, since the cable protrudes ~3" outside the keel slot when the board is vertical, it could still snag weeds if you turn the boat sharply through the weeds. I don't trust the line to stay weed free so I raise the centerboard fully before moving through a weedy area. If I discover the boat has floated into a "salad bowl," I leave the board down as I'm likely to stuff the "salad" inside the slot which is a real miserable job to clear. It happened to me once and it took 2 weeks for weed to rot and drop out, saving me a dive under the boat. In addition, I leave the weed bed in a straight line to improve my odds of keeping the board and lift line clear.
DOUBLE ENDED DYNEEMA LIFT LINE (2022) - Panache's factory SS lift cable was 25 years old when it was replaced in 2002 by diving under the hull. In 2022 it was due for replacement since there were too many broken strands where it connected to the block & tackle. The threat of it breaking during an inopportune moment is not something I looked forward to; been there, done that, no need to repeat it! I have access to only one crane here to hoist the boat and it is available for maybe 30 minutes twice a year. Problem is, they don't allow a person in the boat while it is hanging from the hook and there are no suitable boat stands. Not good enough. So instead of a single ended SS cable I installed Mike Hancock's double ended lift line described above. After waiting 7 years for a hoist to lift Panache, I chose to dive under the boat in mid summer. Replacing this cable is a 2 man job, best done over a sandy bottom to retain visibility. I am looking forward to this being my last dive on the centerboard and easy maintenance of the lift line after that. I couldn't be more pleased with the dead quiet smooth operation of the board and the improved sailing performance with a more vertical board.
SEIZED IN THE UP POSITION - The only good thing you can say about a board seized in the up position is that the boat can still be retrieved on the trailer. Seized in the up position is the most difficult one to release. Some people have been able to push it down with a rod through the table pedestal. The rod has to be 41" long and no more than 7/16" thick so it can't jam inside the 1/2" wide slot. Once the rod is inside the pedestal, gently prod around till you feel the stick on the back of the centerboard. If the end of the rod is notched it can stay centered on the board. You will have about 7" of rod sticking up from the top of the pedestal, leaving enough swing room to tap or pound on it. Leave about 3" of slack on the lift cable so the board doesn't slam down when it comes free. 60 pounds of free swinging steel plate could damage the front end of the slot! Position the rod as far aft as possible and tap on it with a small sledge hammer. Light taps first until you get the feel of it or the board starts to move. The board will hopefully drop the 3" so you can release another 3" of slack and repeat the process till you run out of rod. Stop pounding when the top of the rod is close to the top of the pedestal. Not a lot of point in driving the rod out of sight down the pedestal! This technique worked for Panache's board jammed by weeds and for several other boards seized by fresh marine growth. Not sure if it will work for a heavily jammed or corroded board.
Another time Panache's board was jammed about 300 down due to the SS lift cable that slipped between the board and the inside of the slot. This happened when the boat slid over a shallow sand bank that pushed the centerboard up. Pounding with a rod didn't release the board so I dove under the boat but couldn't push the blade down with my back braced against the bottom of the keel. (What a weird feeling that is under the boat). In desperation I used a three foot long (4x4)" as a lever to pry the board down against the bottom of the keel. It took three attempts, moving the (4x4)" forward a bit each time, till it sprung free. Obviously the leverage of the (4x4)" can push a lot harder than a direct push using my body. Pry small angles at a time to prevent bending the board.
ON LAND - However, if the board is stuck hard (calcium) you might be wiser to repair the job on land so as not to damage the hull. Once on land try removing the marine growth with one of the following ideas, wearing goggles and or gloves:
ON WATER - The problem with freeing the board in the water is that it might stick in the down position, preventing you from retrieving the boat with your trailer. Keep this in mind. But honestly, you should be able to swing the board fore aft to free up the gunk around the pivot point.
When trying any of the above suggestions be very careful with the thin gel coat inside the keel slot. After the centerboard trunk is clean you could apply a liberal coating of antifouling paint with a long soft round brush or a rag on a stick. I'm told that it is amazing how much marine growth can accumulate there in warm water, salt or fresh. In cold, fresh northern waters the slot stays clean. If there has to be a benefit to living with a cold climate, this is it!
NOTE 2: If two hard metals rub together, one of them will wear. If a hard and a soft metal rub together, the wear is minimal. I'm not sure which principle of physics is at work here but I think it has to do with the softer metal acting like a lubricant.
the pivot pin wears badly, I expect it will do so at the top, probably in a
downward slope towards the end of the pin. I've also heard of a pin
that broke off due to corrosion, leaving an angled stub. In
either case the centerboard
will slide down the slope of the pin or stub, where it will wear against the keel trunk and the end of the
pin. As the end of the pin wears thinner, the board will eventually drop to wedge between
what is left of the pin and the opposite side of the trunk,
resulting in a seizure. I've heard of
two boards that
did this so that's
my theory and I'm sticking to it, for now anyway! I sure would
appreciate it if someone else would confirm this. Please email me.