Outboard Hydraulics


Proven in more than a decade of demanding commercial service, the Outboard Hydraulics system bolts onto and draws its power directly from an outboard motor. It provides the small-boat fisherman with access to established, efficient hydraulic haulers for gear such as lobster and crab pots, gillnets, and long-lines. The Outboard Hydraulics package has also proven itself highly effective in powering hoists and winches in other applications as diverse as mooring removal, salmon-pen maintenance, and oil-spill recovery work.

The Outboard Hydraulics system has been successfully fitted to electric-start Mercury/Mariner, Evinrude/Johnson, and Yamaha outboards of 50-235 horsepower. Installation is simple and can be performed by any of our qualified dealers: A keyed hub that bolts to the flywheel accepts the shaft of the kit’s hydraulic pump. The pump itself is attached to a torque arm that bears against the system’s cast-aluminum mounting plate, preventing the pump body from rotating. Because the hub is free floating and centered over the crankshaft, the pump automatically aligns itself as pressure is generated during the hauling operation.


Because of its simple design, the Outboard Hydraulics package is extremely rugged. And, when properly installed, it will not cause any extra wear-and-tear on the outboard and will not interfere with normal maintenance of the engine. At the same time, the unit can be quickly detached to allow for major repair of the outboard or for transfer to another engine.

The line speed capability of the Outboard Hydraulics system has consistently met the demands of small-boat fishermen in the United States, Canada, and abroad. Figure A demonstrates the no-load line speed generated by a typical unit when linked to three different haulers. (Note that performance varies, depending on the model of Char-Lynn hydraulic motor used with the system.) Figure B shows the lifting
capacity of these same units.


The Outboard Hydraulics assembly has been bench and field tested under a wide variety of conditions. Pump output has been measured from 2 to 10 gallons per minute (g.p.m.) at pressures varying from 10 to 2,000 pounds per square inch (p.s.i.). At 1,500 p.s.i. and 3 g.p.m., the hydraulic motor in a typical setup is working well within its design capacity for torque (line pull) and speed.

Figure C shows how pump output varies with engine r.p.m.. Figure D demonstrates how hydraulic-motor output changes with outboard speed for each of the three Char-Lynn units commonly used with the Outboard Hydraulics system. Note in Figure C that the line labeled “recommended engine speed” is used to indicate maximum working efficiency under normal conditions. Up to 5 h.p. can be taken from the unit under the proper circumstances and with compatible components.


We strongly prefer to sell our hydraulics package through established outboard-motor dealers who can handle everything from installation to repairs. However, in cases where there is no dealer nearby, or when a local dealer chooses not to handle our system, we will sell directly to individual commercial fishermen, aquaculture-lease holders, boatyard operators, government agencies, and other qualified customers.

In addition to manufacturing each package at our shop in Waldoboro, Maine, we offer an extraordinary level of support to those who purchase the Outboard Hydraulics kit. Contact us for product ordering and technical assistance, and–when needed–we can talk a buyer through installation procedures and problem repairs.


1. How will installing the Outboard Hydraulics system affect the performance of my outboard motor?
This equipment was specifically engineered to create little additional strain on an outboard. The increase in fuel consumption is minimal (far less than the extra gasoline that would be burned if a Briggs & Stratton-type auxiliary engine were used to drive your boat’s hydraulics). A typical piece of gear, like a trap hauler, draws only 1.5-3 h.p.- a small percentage of a large outboard’s output, even at idle. Furthermore, this minimal horsepower loss occurs only when the gear (in this case, a trap hauler) is engaged.

2. Can the Outboard Hydraulics system be installed on outboards of less than 50 h.p.?

At idle, there just isn’t enough available horsepower/torque in the smaller engines, except for the lightest of applications. The outboard has to be run at high r.p.m. to generate the amount of power required for serious hauling operations, and that sort of usage can appreciably shorten the life of the engine.

3. How much hydraulic flow and hydraulic pressure does the system generate?

Both pressure and flow vary with engine r.p.m. In a typical installation, there is a flow of 3 gallons per minute (g.p.m.) at 1,200 pounds per square inch (p.s.i.) when the outboard is turning at 1,150 r.p.m. As engine speed increases, so do the rate of flow and the level of pressure.

4. How much weight can the system lift?

The capacity of any hydraulic system is a function of the flow and pressure it can generate. The Outboard Hydraulics equipment has the power to lift in excess of two tons, but because of the relatively low flow involved, the rate of lift would be quite slow. Your dealer can help you select the hydraulic motor that will meet the line-speed and lifting requirements of your particular hauling operation.

5. Can a specific Outboard Hydraulics package be transferred from one outboard to another? What if the second engine differs from the first in horsepower and/or brand name.

The important variables are the top-cover casting, the pump cover, and the coupling. The casting is made of aluminum and can often be filed to fit the cowling of the new engine. The molded-fiberglass pump cover is a different matter: The original holes for the inlet and outlet hoses may not be in the right place once the pump has been transferred to the second outboard. But, new top covers are readily available through your dealer.

The coupling usually varies from one brand and size of engine to the next, meaning that this component may not be transferable. Here, too, new couplings of the proper dimension may be purchased through your dealer. All the other components of the system should work with your new motor.

6. If I use additional lengths of hose, can I locate the hydraulic-fluid tank more than 10′ from my outboard?

The farther the pump from the reservoir, the greater the strain on the pump. In other words, the shorter the distance between the outboard and the fluid tank, the longer the life of the pump. We don’t recommend using additional lengths of hose, but if it’s required because of a particular boat’s layout, call us. You will need to use hoses of a larger inside diameter than originally called for, and we can specify the right sizes for your layout.

7. Is a pressure-relief valve furnished with the Outboard Hydraulics system?

Yes. Pressure relief is built right into the valve. If you use a valve other than the one that’s part of our system, it must be a unit of this type.

8. Why aren’t there quick-disconnect couplings at the outboard [pump] end of the system?

Because of their design, quick-disconnect fittings would restrict flow in the hydraulic lines and unbalance the system’s self-centering hub. As a result, the lifting capacity and/or speed of the Outboard Hydraulics package would be compromised.

9. Is the hydraulic-fluid tank large enough to provide the level of cooling required on hot summer days? Can the system handle tropical climates?

In general, the reservoir has enough capacity to handle hot weather. However, like all on-board systems, the Outboard Hydraulics equipment should be checked regularly. If the hoses or tank are too hot to touch, the system is overheating and should not be used in hauling operations.

10. If I need to use the system to power a particular piece of hauling gear, how do I ensure compatibility?

Check the hydraulic motor that normally powers the equipment you’ve chosen, and determines its requirements for flow (in gallons per minute) and pressure (in pounds per square inch). If these specifications match the output of your Outboard Hydraulics package, then the accessory will probably perform as required; if not, you should consult with the equipment’s manufacturer about alternative hydraulic motors.


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