SJ23 Tech Tip D04 - Outboard Mounting Bracket - Reverse the Fulton to Stiffen it

SJ23 Tech Tip D04, (Updated 2024-03-16) Frank May, Bob Schimmel

Outboard Mounting Bracket - Rework the Fulton Bracket to Stiffen it.
INDEX - Saltwater Bracket, Transition Plate, Stiffen Original Fulton Bracket.

The San Juan 23 was factory equipped with a Fulton MB1410 adjustable outboard bracket. While this bracket has hung on Panache's transom since manufacture (30 years at time of this Tech Tip), I babied it for the past 10 years. In my opinion it is over rated for a 20 HP (2 stroke) or 5 HP (4 stroke) long shaft outboard. The bracket may perform OK pushing a planning hull on a mill pond, but it is under rated for a pocket cruiser operating in the heavy pitch and yaw loads imposed by steep 4' waves. You can also find these waves on a shallow lake, at a harbour entrance or where wind and current oppose each other. A steep wave can present some very significant forces. On two occasions I was unable to raise the bracket, the motion was that violent. What surprised me is how much the bracket swayed sideways. So much so, that I thought it was close to bending. 4" of sideways movement on a 14" pivot arm is far too much for my liking. Both times I was tempted to tie a line around the outboard to steady it, but judged the risk of falling overboard too great, along with the fact that I just might

need to use the outboard. The flexing gave me quite a concern, just when I needed to concentrate on boat handling. A Mercury 7.5HP equipped with electric start or a Honda 8HP each weigh about 65 pounds. The Mercury was a popular outboard in the mid 1970s and the Honda about 10 years later. To answer the obvious question of why I'm not sailing in winds that strong? Well usually I do, but sometimes an SJ23 needs some extra punch from the outboard to maintain headway in steep waves. A shoal draft keel has its limitations and adding propeller push is sometimes necessary for a flatter bottomed hull. Not so in a deep keel wine glass shaped hull. After all, it is prudent to be in a safe place prior to the storm, which may require some push from a dependable outboard mounted on a stable bracket.

The locking feature of the lifting arm was the first component to fail and I stopped using it because it would release occasionally. Since I use a 4:1 block and tackle to raise or lower the outboard, I tie the bracket in the 'up' position to prevent it from dropping. "I bloody near go through the roof when the lever lets go in the middle of the night as the outboard drops with a thunk. The sound reverberates through the entire hull, which is particularly annoying when you are in the dream state!"
The other problem with this design is that the closely spaced pivot arms have virtually no resistance to a side load as the boat pitches and yaws through the waves. To make matters worse, the hinge bolts have to be a bit loose so the pivot arms can move up and down which contributes to the overall sloppiness. I had to continually tighten the nuts, testing my confidence in it. The aging bracket shown at left finally wore out and had to be replaced. It was temporarily mounted on a (2x10)". In a nut shell, the old bracket design lacked the stability to hold an outboard steady under all the conditions that mother nature can hand out. There are enough other things to concern yourself with on the water that you don't need a "safety valve" to limit you. So it was time to do something about it.

SALT WATER BRACKET - Many current salt water rated outboard brackets are more robust and rated for a higher horse power. They are also equipped with an internal gas spring that provide lift which makes them an attractive upgrade for a silver haired sailor! Present company excepted! The OMC outboard bracket (shown below) is an example of such a unit. It is rated for up to15 HP and has an internal gas spring that makes raising or lowering a 'piece of cake.' The pivot arms are spaced far apart (sideways) to eliminate sideways movement. Unfortunately, if you don't replace like for like, the mounting bolt holes of the new wider brackets don't line up to the original holes on an SJ23. The narrow outboard mounting "pod" on the transom of an SJ23 makes upgrading to the new wider outboard bracket difficult. The SJ23 pod was sized for the narrow foot of the original style Fulton bracket. The foot print of all the current brackets are much larger.

It should be noted that Fulton MB1820 now has a good design (shown at right) for a pocket cruising sailboat. It is quite an improvement over the early design in that it is more rigid and has all stainless steel parts. I think this is an early design of the MB1810 saltwater bracket that is rated up to 30 HP 2-stroke or 6 HP 4-stroke, max 130 lbs. The 3" wide formed pivot arms are effective at eliminating sideways play and the mounting plates line up to the mounting holes through the SJ23 transom pod. This improved design is what prompted me to stiffen Panache's bracket.

Another good stainless bracket with no sideways movement is the Garelick model 71056. However, it requires an adapter plate to mount to an SJ23.

TRANSITION PLATE to MOUNT LARGER BRACKET - Frank May.

NOTE - "I got this excellent bracket at such a good deal that I didn't want to pass it up. Therefore I designed this transition plate to mount it using the original pod holes."

CONSTRUCTION - One solution to the bolt hole alignment problem is to fabricate an external transition plate from 1/4" aluminum. Frank May did this to "Jafeica" in the Spring of 1998 when he purchased a used bracket.

"Cut the aluminum plate to size and shape and pre-drill the holes before final assembly. The edge of the plate must be ground smooth with a hand grinder. I also recommend installing the plate to the boat first, then the bracket to the plate. Use a piece of solid hard wood and large stainless steel washers against the inside of the hull. Install the bolts with the heads on the inside and the nuts on the outside. This facilitates checking the nuts for tightness in the future. I was a little afraid that the plate might look ugly, but once it's on you don't even notice it. I also replaced all the worn pins with stainless steel for the extra security. Whatever you decide to do, bolting through the hull is a real lousy job that is described in Tech Tip D03 . At left is an image of my transition plate." Frank May.

Here is Mike Forman's experience with a similar installation and a twist to the solution. "The aluminum bolts on my original outboard bracket hour glassed so I replaced them, hoping it would solve the problem. Despite this it was still a beast to lift the outboard so I replaced the outboard bracket (in 2004) with a Fulton MB1820. Like Frank I used a 1/4" thick aluminum transition plate (only $6.00) to deal with the offset holes of the smaller transom mounting pod. I would recommend this technique to anyone. However, the MB1820 is designed for a 10 HP, 4 cycle outboard and there was an overlap between it and the rudder with the bracket in the down position. The overlap prevented full blade travel. So I trimmed a bit off the back of the rudder, above the water line. I figured I best mention this because trimming a rudder with a metal head will be more difficult than trimming my all glass fixed rudder. The new bracket works excellent as my wife can raise and lower it very easily. My next option is electric start so I can really be a captain." Mike Foreman.

When I modified my Fulton MB1410 bracket as described below, I experienced the same overlap problem that Mike had. I solved it by adjusting the height of the bracket in the down position (bottom limit of down travel) and installed a taller outboard mounting block so the outboard rests about an inch higher. This is seldom possible on a retail bracket. It is difficult to determine which outboard bracket will be suitable on an SJ23 as there are many combinations of brackets and outboard sizes. One method would be to clamp the outboard on the bracket and hold it up against the mounting pod. Then swing the rudder to determine if you have clearance. Do this with the bracket in the up and down positions. Here's hoping you find some muscle bound guy to help you! This is not an easy job. Bob Schimmel

Always use a marine sealant or adhesive between the metal plate and the transom to seal the bolt holes and to prevent movement and marine growth between.

STIFFEN the ORIGINAL FULTON MB1410 BRACKET (2006) - Bob Schimmel.

NOTE - "I modified my original Fulton MB1410 bracket, shown at the top, to eliminate the side flex. It took a bit of ingenuity to design a workable modification that also looked good. I wouldn't normally go through all this work except that I wanted to use the same bolt holes on Panache's transom and I don't have access to a retail outlet of outboard brackets. I did incorporate some of the design features of other brackets I have seen."

Modifying the Fulton MB1410 adjustable outboard bracket may have been time consuming but it was pleasurable work. To justify this project I balanced the amount of work versus the cost of a replacement unit. "The fact that a beer was on the table against a successful modification had nothing to do with it but it sure tasted good!" I chose to modify my bracket since a replacement bracket that fits the transom is not available. The modified bracket had to be stronger and safer than the original design or there was no point in changing it. It should also look good and still fit to the outboard pod on the transom. When you consider how much force this bracket has to hold, without failing, all aspects of the redesign had to be considered.

My thought was to interchange the transom angle mounting brackets (left to right), add a few judiciously placed spacers between the pivot arms, plus some other clever tricks, to achieve the required sideways rigidity at very little cost. The final design would look similar to the Fulton MB1810 deep water bracket shown at left. Naturally I chose to reuse a lot of the original parts, otherwise there would be no challenge in this project! However, at some point in this conversion I realized there was no going back to the original design, so assess your conversion and work carefully.

CONSTRUCTION - All parts are stainless steel or aluminum.

DISASSEMBLY - Remove your outboard bracket from the hull in one piece.
Place the hull aluminum angle mounting brackets against a piece of (2x10)" wood and scribe their outline and the mounting bolt holes on the wood. This drawing represents the dimension and mounting holes of your transom outboard pod and will be used during the following fabrication and assembly steps to guarantee a perfect fit. Drill the same size holes through the (2x10)".
Disassemble the old outboard bracket, taking photos to remember how it goes back together! Be careful of the springs when they release. They can do nasty things to your fingers when they let go.
HULL ANGLE BRACES - Interchange the hull side aluminum angle braces left for right, and position them over the lines drawn on the (2x10)" in step 2, lining up the mounting holes to ensure the angle braces are perfectly parallel to each other. Insert 4 bolts and tighten the angle braces to the (2x10)". This simulates the bracket mounted on your outboard pod so the completed assembly will fit. Verify this against your hull to confirm a fit.
PAD ANGLE BRACES - The outboard pad angle braces must also be reversed for a wider bolt placement to the mounting block. See step 10.
PIVOT ARMS - The upper and lower pivot arms rotate on four 6" long x 1/2" SS bolts. There are also a 4" aluminum compression tube over each bolt. Sections cut from an old ski pole work just fine for this. The 4" compression tubes must fit snug between the pivot arms to keep them apart. You can see the upper tube between the pad braces in the photo at right.
A lift spring is fitted just over each aluminum compression tube between the angle braces that mount to the hull. The coil springs fits loosely over each tube but is sufficiently snug to keep the spring from being sloppy. "I reused the original springs to provide some lift. They can't lift all the weight of my 65 lb. Merc outboard, but some lift is better than none. The 2 springs also keep the unit from rattling. I could have installed a gas spring, but that would have complicated the construction too much. Besides, I use a 4x1 block and tackle to lift the outboard so the gas spring is not required. I always store the outboard with the bracket raised to relieve the strain on the spring and to prevent marine growth on the prop."
STIFFEN THE PIVOT ARMS - Install a 4" long (1x3)" rectangular aluminum tube between the left and right pivot arms to stiffen the bracket arm. Use a cut off saw to cut the tube ends perfectly square. This is extremely important as the pivot arms MUST be parallel so the hinges don't bind. Determine where along the pivot arm you will mount the rectangular tubes by operating the bracket through its full range, ensuring that no parts overlap or meet. The pivot arms must also meet flush to each other when the bracket is fully up. This is accomplished by having four equal length arms relative to the pivot points on the hull angle brackets. The tubes are bolted to the pivot arms with two 1/4" SS ready rods requiring 5/16" holes. Tighten the nuts to make the assembly square and rigid. This really stiffens the bracket and is exactly what you are after in this modification.
NOTE: If you insert a wood dowel spacer inside each (1x3)" tube and drill a 1/4" hole through each, it will prevent movement should the nuts loosen. It also keeps the tubing aligned to the pivot arms.
SPRING STOPPERS - The springs must push against something in order to function. Fulton incorporates external springs but you don't need them if you intend to reuse the existing springs, as shown above. However, you have to get creative by mounting two 3/8" SS threaded rods (see parts list below) across a set of pivot arms, just inside the end of each spring. See photo above. Cut the threaded rod to length so the ends are flush with the outside of the left and right pivot arms. Cover the rod between the pivot arms with a nylon sleeve (I used a double barbed hose fitting) so the springs can push against a smooth surface instead of the sharp thread. See photo above. Lock the rods in place with a nylock nut at each end, against the inside of a pivot arm. Don't push the pivot arm out as it will cause binding. For extra security you could spread some sealant between the nut and the ready rod. This will prevent the nuts from turning.
LOCKING BAR - Since you can't reuse the original internal locking bar, you'll have to fabricate 2 new external bars from flat bar stock and a wood handle as shown above. Cutting the slots and key stops is the most difficult part. I leave this part to your ingenuity as I borrowed a vertical milling tool. Nice to have friends with tools like this! You could also drill two end holes and cut out the middle with a metal jig saw. Its brutal but it can work. Just make sure that the slots and the stops are identical in both bars otherwise you will experience binding. You'll have to experiment with the position of the key slot as this is what determines how low the prop is in the water and also how high the propeller clears the water.
For the handle drill a 3/8" hole through a 1" hardwood dowel. I prefer wood over metal because it is cleaner, warmer and provides better grip for the hands. Use 3/8" SS ready rod through the dowel and nylock nuts on the outside to bolt it in place. Make sure the dowel can't roll in your hand as a fixed handle makes the lift much easier than one that rolls. Coat the dowel with Sikkens Cetol Marine on all four sides.
NOTE: In the photo above it shows only one key notch to hold the outboard up. I have never seen the need for adding other notches for shallow water drive but you may do so if you think in necessary.
OUTBOARD MOUNTING PAD - Fabricate a new wider outboard mounting pad to span the wider bolt placement of the upper angle brackets. A wider pad allows you to position the outboard left/right so it can't touch the rudder. This pad MUST be exceptionally strong to support a ~65 pound outboard. If it breaks, the outboard is going to the bottom. Yikes. (Be wary of a brittle acyclic pad rather than a flexible polyethylene pad). To offset this, I tie the 4:1 lift cable to the outboard. I epoxied two layers of 3/4" plywood together since laminated wood is stronger than solid wood. For additional strength, soak the plywood in epoxy. Remember to saturate the insides of the bolt mounting holes. Apply four of coats of Sikkens Cetol Marine over the epoxy to protect it from UV.
2007 - I got tired of maintaining the Cetol that my outboard chewed up so as an experiment I replaced the mounting pad with recycled plastic board to make it maintenance free. I have no idea what the correct name for this stuff is as it was given to me. This stuff is battleship grey, is impervious to UV and is far less expensive that Starboard. It is manufactured in 3/4" thick sheets so I glued three layers together using contact cement. It is the only adhesive that worked. I used lots of C clamps to apply uniform pressure to squeeze the assembly together for at least 30 minutes. Pounding does not work. Different huh? Once cured I trimmed the edges with a table saw and drilled the mounting holes 1/32" undersize. Then I used SS carriage bolts and large washers to fasten the pad to the bracket.
2015 - The contact cement held fine for 7 years till water crept into the joint. This time I repaired it with G/Flex epoxy, which is what is holding the laminates in this photo. I let it cure at room temperature for about 4 days, scraped off the squeezed out epoxy with a sharp chisel and sanded each face smooth. But winter was coming and I had to install it on the boat. I'm happy to report that at the time of this photo the pad froze four times and still shows no deterioration. The laminate is now more rigid than the contact cement I originally used and has supported the outboard just fine since.
2018 - I accidentally stood on the mounting pad with my full body weight to lubricate the masthead sheaves and much to my surprise found it to be rock solid.

TESTING - Test the assembled bracket by operating it through it's entire range, twisting it and pushing it sideways. There should be no stiffness or binding with minimal to no play. Nice and stiff huh? In my case the improvement between the old and the modified bracket was night and day. In fact, a few years later I accidentally stood on the bracket to lubricate the masthead sheaves and much to my surprise found it to be rock solid. I thought I was standing on the transom. Oops. The redesign was never intended to hold a person. You might have some initial binding or stiffness in the hinges which could be due to over eager tightening of the nuts or bearing holes. Use your discretion in adjusting them but a drop of oil in the joints wouldn't hurt. Finally, clamp the assembled bracket on a workbench vice, still mounted on the (2x10)". Then hang your outboard on it to test the outboard bracket under load, raising and lowering it through its full range. Better to find the faults now than to discover it doesn't work on the transom!

PAINTING - If you decide to paint the aluminum components, wash them first with a mild acid to remove any grease, then sanitize with acetone and finally prime the surface with a coat of zinc chromate. Zinc chromate is nasty stuff to breathe so paint outside in a mild wind (nobody downwind) and wear a mask. Flat black paint matches the toe rails but the aluminum will get very hot in the sun. I abandoned this idea, thinking that the paint will likely bung up the hinges. Anodizing them in black would have looked nice but I wanted to go sailing. The aluminum has since acquired a very acceptable patina from exposure to the lake water and it blocks further oxidation.

MOUNTING - Once you are satisfied that the bracket works, mount it on the transom using Sikaflex or butyl rubber between the hull and the angle mounting plates to seal the holes and prevent marine growth. Use nylon lock nuts inside the hull backed up with large SS washers against a sealed hardwood block. If you measured correctly, your modified bracket will fit perfectly over the old mounting holes.

Parts List

HINGE BOLTS - Four (6x1/2)" stainless bolts equipped with nylon lock nuts and 4" aluminum spacer tubes.

MINIMIZE FRICTION - 10 thin fiber washers to minimize friction between the arms.

STIFFENERS - Two (1x3)" rectangular aluminum tubes and 1/4" ready rod equipped with nylon lock nuts.

SPRINGS - 3/8" ready rod each equipped with nylon lock nuts and nylon spacers.

HANDLE - (1 x 1/4)" aluminum flat bar, 3/8" ready rod equipped with nylon lock nuts and a 1" dowel.

PAD - Four (5/16 x 2)" elevator bolts, 3/4" thick plywood, WEST epoxy for strengthening the plywood, Sikkens Cetol Marine for coating wood, if you choose recycled plastic board as an alternative to plywood you can dispense with the epoxy and Cetol Marine.

Sikkens Sikaflex for bedding and sealing.

Ready rod is a trade name for continuous threaded rod. It usually comes 36" long in various sizes and metal.

FIELD EXPERIENCE

My first observation of the modified bracket is how rock solid it is. The robust convenient front mounted handle makes lifting and locking the outboard much easier. Now it is much easier to raise or lower the outboard, something I'm looking forward to. The outboard also operates significantly quieter. The rattles I heard never came from the outboard! This is great news because I seriously considered overhauling it.
The pivoting action of the arms was a bit tight when first put into use and the locking bar was really stiff to operate. Both have since smoothed out with use and operate just fine. The new locking bars have never released, also great news. However, I still tie the block and tackle lift line for security.
One thing I hadn't taken into consideration in this modification was the protruding T handle clamping screws of my Merc outboard. The large T handles, while easy to turn, prevented the motor from resting fully down on the mounting pad. So I cut the T handles off and flattened the screw ends so they can be tightening with a wrench. Good theft prevention! Nothing like a bit of field experience to iron out the last few bugs.
If you find the bracket lowers too far, install a stopper bolt across the bottom. This is actually easier on the assembly than shortening the lift line.

HINT - Here is a tip to ease outboard installation on the bracket, assuming you are on the launching ramp with the boat on the trailer. You aren't getting any younger and don't let your ego get in the way to wreck your back! Tie a ~10' long line in a loop secured to the bottom of the bracket and pull the bracket down to the bottom of its travel. Place your foot on the loop of line to hold the bracket down. Now lift the outboard up onto the bracket (keep your back straight) and tighten the locking handles. This is much easier than fighting the lift springs. You're not going to win that battle. Holding the bracket down prevents the springs from following the outboard when you lift it up! Clever huh? Reverse the procedure to remove the outboard.

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