Boat travel from New Orleans or Miami to DR?

[Mistere]

Hello,

As I'm sure this subject has already been covered I tried using the search function in this forum but it seems to not to be working right now.

I would like to take a boat to DR in late February preferably from New Orleans. I have done some Google searches but have not found any confidence inspiring information that way.
I'm a budget traveler and am therefore not looking for anything like a luxury cruise ship. I would be just as happy, in fact I would probably prefer, hitching a ride on a cargo vessel or crewing on a private boat.

I am about to purchase the Rough Guide to the DR. Does anyone know if this guide book covers the possibility of taking a boat from the US to the DR?

Maybe this idea is not worth my trouble and I am better off just taking a flight from Miami but I would like to hear some input from others before writing off the boat idea first. I usually prefer to take the less traveled route in my journeys which have sometimes proven to be the most rewarding.

For some background on why I am making this trip, I am considering teaching English in the DR for a while to decide if it is a place that I may want to spend more time than a few weeks of vacation time at. Currently I have more time than money to explore my options.

Thank you in advance for any information!