The Southern Neighbourhood Policing Team is asking for witnesses to come forward after incidents involving boats.
In the first, a boat in the Castletown harbour boat park was entered and a red marine petrol tank stolen.
Vandals also damaged a boat in Port St Mary boat park when they managed to get inside it.
Both incidents happened in the last six weeks - if you have any information you can contact police headquarters on 631212.
Framework of new Sea Services Agreement ready, says minister
Attorney General says he's stepping down
Road closures in two towns for running event this week
Six weekend ferry crossings could face disruption
President of Tynwald announces retirement
Police close Mountain road
Fuel firm says "fingers crossed" for calmer energy costs
Ring doorbells will need data protection registration - but shouldn't cost you money