|SJ23 Tech Tip D04, (Updated 2008-12-05) Frank May, Bob Schimmel|
Outboard Mounting Bracket - Rework the Fulton Bracket to Stiffen it.
|The San Juan23 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 the wrong design for a pocket cruiser operating
in the heavy pitch and yaw loads imposed by 4' steep waves.
You can also find these types of waves on a shallow lake or at a harbour entrance or where wind
and current oppose each other. This type
of wave can present some very significant forces. For example, 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 in the heavy weather. So
much so, that I thought it was close to
bending. 4" of sideways movement on a 14" arm is far too much leverage for my
liking. A couple of 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 start
the outboard. The bracket never
failed but the bend 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 I need the 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.
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 lever was the first component to fail and I stopped using it because it would release occasionally. Since I use a 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 arms have virtually no resistance to a side load as the boat pitches and yaws through steep 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. The aging bracket finally wore out and had to be replaced. It is shown at left, 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 to a pocket cruiser. There are enough other things to concern yourself out on the water that you don't need a "safety valve" to limit you. So it was time to do something about the problem.
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. This 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) designed especially 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. A great improvement from Fulton's early designs and the style of bracket I suggest is appropriate for an SJ23. This design is what prompted me to stiffen my bracket.
Another good stainless bracket with no sideways movement is the Garelick model 71056. It does require an adapter plate to mount to an SJ23.
EXTERNAL TRANSITION PLATE - 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 and grind the aluminum plate to size and shape and pre-drill all 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 dock washers against the inside of the hull and 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 frankly 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 1820. 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 1820 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.
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 underneath.
REVERSE the ORIGINAL FULTON MB1410 BRACKET to STIFFEN it - Bob Schimmel.
NOTE - "I modified my original Fulton MB1410 bracket, shown at the top, to eliminate the side movement. 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 these brackets. I incorporated some of the design features of other units I have seen. There was also a beer on the table, stating that it couldn't be done. Sure tasted good!"
MB1410 adjustable outboard bracket may have been time consuming but it was pleasurable
work. To justify this project you have to balance the amount of work versus the cost of a replacement
unit. The fact that a beer was on the line against a successful modification
had nothing to do with it! I chose to modify my
a replacement bracket that fits the transom is not available.
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 that to
interchange the transom angle
(left to right) and add a few judiciously placed
spacers between them, plus some other clever tricks, it should achieve the sideways rigidity
I require at very little cost. The final design will 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 there may be no going back to the original design if it doesn't
work. So assess your conversion and work carefully.
CONSTRUCTION - All parts are stainless steel or aluminum.
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 lethal stuff 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.
you are satisfied that the bracket works, mount it on the transom using Sikaflex 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 stainless washers. If you measured
correctly, your modified bracket will fit perfectly
over the old mounting holes.
- Here is a tip to ease outboard installation and removal from the high 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. To remove the outboard, tie the line to the
hold the bracket down with your foot and lift the outboard up from the
bracket. 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?
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