Methods and systems for controlling trim rate of trimmable marine devices with respect to a marine vessel

A method of controlling tilt-trim position of a trimmable device on a marine vessel, the method comprising:

• receiving a vessel speed of the marine vessel and an engine speed and/or an engine operation state for an engine on the marine vessel;
• determining, at a controller, a trim rate based on at least one of the engine speed, the vessel speed, and the engine operation state, wherein trim rate specifies a rate of rotation of the trimmable device about a horizontal axis;
• measuring a trim position of the trimmable device;
• determining a trim rate multiplier based on the measured trim position, wherein the trim rate multiplier is a value between zero and one and wherein the trim rate multiplier decreases as the trimmable device approaches a maximum position or a minimum position;
• determining a reduced trim rate based on the trim rate multiplier;
• and
• controlling a variable speed trim actuator to rotate the trimmable device based on the reduced trim rate as the trimmable device approaches the maximum position or the minimum position.

A variable speed trim system on a marine vessel, the system comprising:

• a trimmable device;
• a variable speed trim actuator configured to rotate the trimmable device about a horizontal axis so as to adjust a trim position of the trimmable device;
• a controller configured to:
• determine a trim rate based on at least one of a vessel speed of the marine vessel and an engine speed of an engine on the marine vessel, wherein trim rate specifies a rate of rotation of the trimmable device about the horizontal axis, and wherein the trim rate is determined such that the rate of rotation is minimized at high vessel speeds and high engine speeds and the rate of rotation is maximized at low vessel speeds and low engine speeds;
• and
• control the variable speed trim actuator to rotate the trimmable device based on the trim rate so as to adjust a trim position of the trimmable device.