Not really a 'bum boat' as such. It's one of the mooring boats ships carry through the canal should the vessel need to moor during the transit. The two man 'crew' would certainly set up shop somewhere selling the usual Suez stuff. 'Bum boats' were the unofficial boats that tended to swarm around ships at either end of the canal, but particularly at the Port Said end when tied up to the buoys. The 'crew' of these boats would come onboard to sell just about anything or 'lift' anything not bolted down securely. A subtle difference, but an important one!