We had a fantastic experience with Marine Dynamics. A presentation is given prior to boarding the boat by a Marine Biologist who explains about the projects they are running to help protect the environment and look after the sharks.
We took our 8 month old baby and 5 year old son along, They were fine, the baby slept through most of the trip and our older child had a fantastic experience and was able to actually see (from the boat) the beautiful animals that we have spent many hours watching on the discovery/NatGeo channels. Prior to booking the trip we went to speak at length with the Captain Henny about whether this would be suitalbe for the children, Henney checked the weather reports and explained what would happen on the trip and that if we didnt like it or didnt feel comfortable they would send another boat out to collect us (at a cost of R400, approx £36).
We choose a good day weather wise to make our trip, not much wind and pretty much a flat calm. Nobody was sea sick at all. We had visibility of about 5 meters-perfect for seeing plenty of Great whites and also the seals along shark alley.
Safety was also of paramount importance, you are told exactly what to expect and life jackets fitted by the team prior to getting on the boat. The boat is only about a month old and very nice. We were given a light lunch and then also some soup and sandwiches when arriving back whilst they play a dvd of our trip (which you can buy if you like).
All Staff were extremely professional, Henney, Alison and Nick were absolutely fantastic and extremely knowledgeable and helpful.