Here's another version, different from the above only in minor details. I have no idea which version is closer to the original. Copied from http://lyricsplayground.com/alpha/songs/m/messingaboutontheriver.html

MESSING ABOUT ON THE RIVER
(Tony Hatch / Les Reed)
Josh MacRae - 1962
Danny Kyle - 1998

When the weather is fine, you know it's the time
For messin' about on the river.
If you take my advice, there's nothing so nice
As messin' about on the river.
There's big boats and wee boats and all kinds of craft,
Puffers and keel boats and some with no raft.
With the wind in your face, there's no finer place
Than messin' about on the river.

There are boats made from kits that'll reach you in bits
For messin' about on the river.
And you might want to skull in a glass-fibred hull.
Go messin' about on the river.
Anchors and tillers and rudders and cleets,
Ropes that are sometimes referred to as sheets.
With the wind in your face there's no finer place,
Than messin' about on the river.

Skippers and mates and rowing club eights
All messin' about on the river.
Capstans and quays where you tie up with ease,
All messin' about on the river.
Outboards and inboards and dinghies you sail.
The first thing you learn is the right way to bail.
In a one-man canoe you're both skipper and crew,
Messin' about on the river.

Moorings and docks, tailors and locks,
All messin' about on the river.
Whirlpools and weirs that you must not go near,
Messin' about on the river.
Backwater places all hidden from view,
Mysterious wee islands just waiting for you.
So I'll leave you right now, go cast off your bow,
Go messing about on the river.