Copying files to to a hard drive so you can reuse your CF cards, is slow, expensive and risky.
i would not agree too much with this statement, it may be slower, but hey your on a nice livaboard and it can be done whilst you are having some chill out time, why is it expensive? once you have the portable HD you have it, I paid £40 GBP for a 60GB freecom portable HD and £75 GBP for a 160 GB HD. and why is it risky? there are risks involved in all forms of data storage/transfer and storing for short duration i would not say that a portable HD is that much of a risk.
CF is way more durable and reliable than a hard drive.
storage for long periods of time may be, i would be interested to know how many people have had serious issues with portable HD
Especially in the harsh environment of a boat.
what kind of liveaboards do you go on. the ones i go on have nice cabins, clean and dry. Not harsh at all.
There is no way I would go back to hard drives for on-site storage.
obviously you have had A problem with a portable HD
the cheapest option for you i feel would be too take a few blank dvd's with you and get one of the guys on the boat to write them too disc for you. I have done this for people on liveaboard loads of times. i have used a portable HD for over 7000 photos and for over 50 hours of video and i have not had any issues.