For those who need help getting their luggage to their accommodation, there are a couple of options. Hotels, guesthouses, pensions, and private houses, if apprised of your time of arrival, will often meet you off the boat and direct you to your accommodation. Luggage handling may or may not be included in their services, so be sure to check with your hotel or house manager. If it is not, you can always ask them to arrange for the transfer, which you will pay for (in cash) on your arrival. If you will be organizing your own luggage transfer, you have two options: mules and handcarts.
Handcarts operate in the areas of Hydra Town without stairs for a flat rate of €10 for a unlimited number of bags (as long as they all fit, of course). The fee does not include carrying the bags from the cart up any steps to the accommodation, but some operators will help you with this, though you might want to discuss this beforehand.