Ill bet its a bit steep-I hope your fee is Darren, look out for the rain forecast firstly and of course it will be pitch black when you come off the boat==so have lighting available, I dont expect there will be much, these type of places are often a bit Spartan when it comes to getting on and off.
I would treat comments like--other DJs do it all the time no problem with a large sack of salt.
They would say that.
I think you will find Health and Safety generally poor in these locations.
Good luck with it Darren anyway--
My experience of event companies is lets say a little chequered--unless of course you know and trust them.