Rats and mice on board ships are an age-old dilemma. When I first went to sea most ships had cats on board to handle the problem – with varying degrees of success. Now, with strict international quarantine laws, cats are no longer a realistic option. In the past commercial ships had to obtain and carry a de-ratting exemption certificate, renewable every six months to show there were no pesky rodents on board. This certificate was replaced in 2007 by the Ship Sanitation Control Exemption Certificate/Ship Sanitation Control Certificate – much more PC.
I know from experience how difficult it can be to get rats off a ship. One beautiful ocean liner I sailed on had a persistent rat problem that took months of warfare to eradicate, each generation of rats becoming more devious, cunning and evasive than the last. Rats have a wonderful sense of smell and an extraordinary ability to navigate complex spaces in the dark. Don’t underestimate them.
Firstly, the obvious fact is that prevention is better than cure. Making the boat less attractive than your neighbours boat and difficult to access is the first step. Keep the boat away from the dock, rig ratguards on mooring lines and shut hatches etc where possible. For yachts ratguards can be purchased online or simply fashioned in a number of ways quite cheaply. A large plastic water bottle with the bottom chopped off threaded onto the mooring line, a frisbee with a centre hole and a slit on the mooring line, a length of greased plastic pipe on the mooing lines etc. These simple measures will stop mice and rats climbing on board on the mooring lines. Dorades can be fitted with wire screens to allow ventilation but stop pests. But remember, given time rats and mice will chew through almost anything to get access to food.
If you have mice or rats on board, let us call them rodents, the first indication is usually small holes in food packets. Further investigation will quickly turn up droppings. This is the time to take things very seriously. Hard and fast action is needed to eradicate the problem and win the war. Without action one rodent will multiply to many and some serious damage can be inflicted on the boats interior and systems.
Immediately remove all food sources and secure them in rodent proof containers or if possible, get all food off the boat and store ashore. Dispose of any food packets that have been broached. Next clean all cupboards, shelves, lockers, spaces, drawers and wash with bleach solution. Keep all drawers and lockers open if possible. The aim here is to implement a scorched earth policy, denial of anything that may be of use tyo the enemy. A foodless, clean and disinfected environment is not attractive to rodents. I have used tumble dryer pads or scented dryer sheets in cupboards, drawers and shelves to good effect. For some reason rodents can’t stand them and they give the accommodation an unusually fragrant smell. Mothballs are another common nasty smelling deterrent.
Next step is to get the rodents off the boat – dead or alive! If, after the removal of all food, cleaning and sanitation measures the rodents depart of their own accord all the better, for everyone. With this in mind, it must be easy for the little monsters to get ashore. So, remove ratguards and keep the boat close to the dock so the guests can easily go ashore and visit elsewhere. In the likely event that your guests do not take the hint to depart traps must to be set. Standard old-fashioned rat and mouse traps work well, bait with a bit of fatty bacon or peanut butter. Do not use poison, believe me, the smell of rotting dead rat is truly horrific. Handle any dead rodents and their droppings carefully, good personal sanitation is needed.
Taking these simple measures early will hopefully get rid of the rodent problem and make your boat unattractive to future visitors. By taking strong decisive early action the rodents will not have the opportunity to breed extensively or inflict damage to the boat or its systems. It is however a good idea to check all cables, wires, pipes for damage once the rodents have departed.