Boating - July 2018

42 | BOATINGMAG.COM | JULY/AUGUST 2018

BOAT DOCTOR ///QUICK STUDY

If emails to the editor and anecdotal

information from boatbuilders and boat

dealers is any indication, a substantial number

of boaters express confusion about how to

trim their boats’ engines or drives. Certainly

this applies to getting on plane, adjusting for

load, trimming for ride comfort or to suit sea

conditions, and more. Let’s review the basic

principles of how to trim an outboard or

sterndrive boat through turns. —Kevin Falvey

1. INTO THE TURN
   While cruising along,
   you’ll approach the
   turn with your drive
   trimmed out (up).
   This allows you to
   maintain some speed
   and ensures the
   boat begins tracking
   through the turn on its
   after sections. You do
   not want to approach
   a sharp turn with the
   trim all the way in
   (down) because that
   might cause the bow
   to dig in, and the boat
   theoretically could
   spin out or even swap
   ends. Instead, begin
   the turn at cruising
   trim, and then “ride”

the trim switch down

as you approach the

apex of the turn.

2. ROUND THE
   CURVE As the boat
   reaches the apex of
   the turn, you feel it
   begin to slow down
   because you now have
   a larger portion of
   the hull length in the
   water. With the drive
   trimmed down, the
   stern is less likely to
   break out and you can
   accelerate safely, add-
   ing the rpm necessary
   to regain — or even
   maintain — speed. The
   timing of this depends
   upon the boat ( boats

with more buoyancy

in the bow might

require less trim) and

sea conditions (you’ll

be going slower with

more negative trim in

choppier water).

3. OUT OF THE
   TURN As you leave
   the apex of the turn

and accelerate onto

your new course

heading, you’ll do the

opposite of what you

did in Step No. 1. Ride

the trim switch, trim-

ming the drives out

(up) while accelerat-

ing until you fi nd your

cruising speed and

trim. Of course, now

that you are headed in

a di erent direction,

you’ll be hitting waves

and running with

respect to the wind

di erently than you

were before the turn.

Adjust as required;

there is no “perfect”

amount of trim for a

given boat speed.

QUICK TIP

Remember: If the drive is trimmed up, the bow will come up. If the drive is

trimmed down, the bow will come down.

ILLUSTRATIONS: TIM BARKER; PHOTO: COURTESY MERCURY MARINE

HOW TO

TRIM

THROUGH

TURNS

Three tips for optimizing trim, perform-

ance and handling while cornering.

This system is tough to beat — we’ve tried and

basically couldn’t trim the test boats any better

than Active Trim. It can be turned off for manual

control and is compatible with 40 to 400 hp

Mercury outboards, and all gas and diesel

MerCruiser sterndrive engines with SmartCraft.

MERCURY

MARINE

ACTIVE

TRIM

Trimmed down

and ready to add

throttle here.

Begin trimming

down as you lean

into the turn.

Ride the trim

switch up to

re-establish

cruising.