Trailers and marine · TM-03

Boat Trailer Inspection Checklist

A free printable boat trailer inspection checklist — bearings, immersion and corrosion, rollers and bunks, winch strap and the lighting board.

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2 pages. Choose your paper size — both versions are laid out identically, so neither one gets shrunk to fit.

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A4 58 kB US Letter 58 kB

Fill it in type and save

A4 97 kB US Letter 97 kB

The fillable versions have real form fields — open them in any PDF reader, type into them and save. Printing help.

What this sheet is for

Inspect the things that only go wrong on a trailer that gets driven into the water — wet bearings, corrosion from the inside, and a winch strap nobody has unrolled in years.

Who it is for

Boat owners who launch from a trailer, especially anyone using slipways in salt water.

How to use it

Check the hubs are cool before the trailer goes in — heat is what draws water in.
Unroll the winch strap to its full length and look at all of it.
Rinse the frame, not just the wheels, and make sure the drain holes are clear.
Record what you found each time so bearing problems show up as a pattern.

What is on the sheet

2 pages, in this order:

Page 1

Printed under the title: An inspection for a trailer that gets driven into the water. Immersion, and salt water above all, does things to a trailer that no road trailer ever has to survive.

Heat, water and salt. A hot hub dunked in cold water draws water in past the seal as it cools, and salt left inside a box section works from the inside out where nobody looks. Let the hubs cool before launching, and rinse the whole frame with fresh water afterwards — including the inside, through the drain holes.

Write-on lines: Trailer make & model · ID / registration · Date · Boat & weight · Usual water · Checked by

Bearings, hubs and immersion

Bearing protectors seated, turning and holding grease
Hubs cool to the hand before the trailer goes in the water
Grease inspected — milky means water has got past a seal
Play checked at the top and bottom of each wheel
Seals, dust caps and hub nut retention sound

Corrosion

Whole frame rinsed with fresh water after every salt launch
Drain holes clear so box sections empty instead of holding brine
Galvanising or paint intact; no bubbling or flaking at the welds
Spring hangers, U-bolts, shackles and axle checked for section loss
Brakes, where fitted, flushed and freed off after immersion

Page 2

Rollers, bunks and supports

Rollers turn freely and have no flat spots
Bunk carpet sound, with no exposed staples or bolt heads
Keel rollers aligned and carrying weight where the hull is strong
Boat sitting square, hard against the bow stop

Winch and securing

Winch strap or wire run out full length and inspected end to end
Winch hook, safety catch, ratchet and brake pawl all working
Separate bow safety chain fitted as well as the winch strap
Transom or stern straps tight, and re-checked after a few miles
Outboard supported, and mast, fuel and loose gear secured

Lighting board and electrics

Lighting board removed or unplugged before the trailer enters the water
Board mounted high, clear of the water, and secure
All lamps, plug, socket and cable checked with someone watching

Signature strip: Signed · Print name · Date

Ruled lines: Notes and anything specific to yours

Questions

Why do boat trailer bearings fail so much sooner than road trailer bearings?

Because they get hot on the drive to the slipway and are then put into cold water. As the hub cools the air inside contracts and draws water past the seal, and the water sits in the grease. That is what bearing protectors are trying to prevent, and why letting the hubs cool first matters.

Does the lighting board really have to come off?

Immersing road lights is what kills them and their wiring, which is why removable boards exist. What you must display, and when, is set where you are — the sheet records that the board was dealt with and that everything worked afterwards.