As anyone who's had a near miss with a bear will tell you, it's not just their claws you have to worry about; it's their razor-sharp teeth. Normally, a bear's powerful teeth would be something to be wary of, but the fishermen realized that they might be the key to survival here.
When the cub became too tired to hold on using its arms, it bit the boat and used its teeth to stay afloat instead. That's when the fishermen had an idea.