Chris-Craft Launch 22 Owner's Manual download pdf (Page 90)

3–28 Chris-Craft

Systems

Theory of Operation

Trim tabs are used to modify the running angle of the boat. The Chris-Craft is designed to plane at a partic-

ular speed and weight distribution. As weight increases and/or speed decreases, the stern settles creating an

inefficient, untrimmed condition. In this bow-high position, visibility is limited, fuel economy is poor and

wake is large. Additionally the hull bottom may be pounded by waves. Trim tabs allows the vessel to plane

at heavier loads and slower speeds than the designed planing speed.

Increased trim may improve the ride in a head sea by allowing the bow to cleave the waves, rather than

pound over them. In a following sea, the tabs should be fully retracted for maximum steering response. A

listing condition may be corrected by applying more trim on one side. Too much trim will increase the drag

and cause the bow to “dig in” allowing wave action to veer the boat.

As the owner/operator, it is you responsibility to understand how trim tabs affect the characteristics of the

boat. The Trim Tab Owner’s Manual that accompanies this vessel provides additional operating and safety

instructions, which is not repeated here. However at a minimum:

• Use trim tabs only at cruising speeds.

• Do not use more tab than is actually needed for good performance.

• Do not reduce the running angle less than 2°.

• Do not use the trim tabs when backing or running an inlet. Damage to the cylinders and tabs my result.

• Fully retract the trim tabs when trailering the boat or if leaving the boat to sit in the water for any extended length

of time.

• Spend time getting familiar with how the trim tabs affect the vessel.

• Improper use of the trim tabs can cause an accident and/or injury.

Trim Tab Hydraulic System

The trim tab hydraulic system is comprised of the following components:

•Hydraulic Pump

• Reservoir

• Hydraulic Cylinders

Trim Tab Hydraulic Pump

The trim tab hydraulic pump is a 12VDC electric-driven pump. When activated, the electric motor pumps

hydraulic fluid to the hydraulic cylinder located on each tab. The high-pressure oil drives the piston down-

wards and pivots the aft section of the trim tab down below the bottom of the boat.

Trim Tab Reservoir

A hydraulic reservoir is built into the base of the pump. Fluid is drawn from the reservoir when the tabs are

driven downward and returned to the reservoir when the tabs retract.

Verify fluid level in the hydraulic pump reservoir on a regular basis. With the trim tabs completely

retracted the fluid level should be about two (2) inches from the bottom of the reservoir. To refill, remove

lexan cover and filler plug located at the front left hand corner of the reservoir. Fill with any type of Auto-

matic Transmission Fluid (ATF) only. Brands of ATF can be mixed.

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Chris-Craft Launch 22 Owner's Manual Page 90