PERSONALLY.... I provide the porters $1 - $2 per bag they handle.....many will say you do not need to...some are of the belief that tipping the porters is "insurance" to be assured you luggage gets loaded onto the ship...(personally I think this is a load of crap !) then others are opposed to tipping due to the salaries the "long shoreman" (doubling as porters for extra $$) make annually. I cant recall which port has a sign stating "Gratuities not required to be paid to porters".... so there you have the basic responses you will probably get from your querry !