Ignoring the panic-struck woman on the bank, he flashed past her and galloped, body-deep, into the water; toward the swaying canoe.
Here he paused.

For Lad was anything but a fool.

And, like other wise collies, he had sense enough to realize that a swimming dog is one of the most helpless creatures in the universe; when it comes to self-defense.
Ashore, or in water shallow enough to maneuver his powerful body, Lad could give excellent account of himself against any normal foe.

But, beyond his depth, he would fall easy victim to the first well-aimed paddle-stroke.

And he knew it.