Video report by ITV reporter Richard Slee
The police are investigating 9 incidents where lasers have been shone into the eyes of ship masters in the Solent.
The incidents happened earlier this month at night, causing some crew members to be temporarily blinded.
Jack Ettridge from the Marine Support Unit says the police have stepped up marine patrols and stresses this is a highly dangerous thing to do.
"Fairly obviously if you blind someone who's steering a ship and they go off course, particularly in this environment, there's quite a small channel for these larger ships as they come in and out of Southampton and it takes quite a lot of skill and navigation to get around that corner.
"They can hit small ships quite easily. There's a high risk to other boats and other vessels, not to mention the fact that they could easily hit the side of the channel and end up blocking it."
The offence of pointing a laser at a ship is included in the legislation that covers lasers being pointed at aircraft and blinding pilots.
Anyone who has information about who might be responsible for shining these lasers at ships should call the police on 101.