With the boat you are travelling in nature, there is water, food in the locker, and often the yacht lies uninhabited at the jetty. Really uninhabited? Because the conditions for uninvited guests are good: there is plenty of food and undisturbed corners. Especially in tropical areas, pests can quickly become a nuisance on board. Whether cockroaches, flies or mice, vermin always pose a risk of infection.
In general, there are two strategies against pests: prevention and control. Ideally, all measures should be taken to prevent pests from getting on board in the first place. But that doesn't always help, so it's good to be prepared. Fruit flies, moths and cockroaches should be kept away as a preventative measure through the correct bunkering and stowing of food, as well as the correct handling of food waste. Once on board, they will otherwise multiply explosively.
Mice or even rats are fortunately rarer, but the danger is particularly high in winter when the boat is uninhabited and food is still stored in the lockers. Rodents can cause substantial damage when building nests and with their droppings. It helps to block access points and remove food.
Mosquitoes are most common and annoying in summer. In tropical areas they are also disease carriers, but on the North and Baltic Seas they are usually just annoying. Nets and special sprays are the best way to deal with them. Spiders are actually considered useful, but the nets are a nuisance if they block the clicker, for example. We have compiled some tips against pests below.
Cockroaches
These little crawlers are almost superheroes: They can fly, hide in the smallest crevices and are so well armoured that they are almost indestructible. But nobody wants them on board. That's why special precautions should be taken when bunkering fresh food. Cardboard packaging is not allowed on board. Cockroaches like to lay their eggs in boxes of fruit. And even if there is nothing suspicious to be seen, the little ones hatch and become a nuisance on board. So clear out all boxes on the jetty and stow food on board without packaging.
But cockroaches can also fly. That's why an anchorage too close to shore can be fatal. Once they are on board, it is difficult to catch them. Special traps can help. A trap can also be improvised on board using sugar and rum: Put sugar and a little high-proof rum in the glass and leave it open. The cockroach will want to eat the sugar and remain lying there, anaesthetised by the alcohol. It can then be thrown overboard.
Fruit flies and moths
Food moths or fruit flies can destroy food supplies and also simply cause a nuisance due to their abundant presence. An infestation of these pests is usually a home-grown problem if food sources such as flour, cereals, fruit and even rubbish are easily accessible. All food should be stored in sealable containers or in a cupboard. If fruit spoils, dispose of it quickly and also store rubbish in sealed containers.
If it is already buzzing on board, traps can also help here. These can be purchased from specialised retailers or online. There are also ways to improvise with on-board products. Vinegar or sweet drinks attract fruit flies. A drop of washing-up liquid reduces the surface tension of the liquid so that the fly sinks into it when drinking. On board, it is important that the trap is secured, otherwise it will spread its contents all over the boat.
Mice and rats
Mice and rats are not normally an issue on board during the season. Only the choice of berth can cause nasty surprises. If you moor next to a restaurant and there are rubbish containers with food waste right next to the berth, then rodents can also find their way on board. Although this is unlikely, the accessories trade offers so-called rat trays. These round deflectors are pulled over the mooring line and block the way on board.
Mice and rats can become more of a problem in the winter months when the boat is uninhabited for longer periods. But there are two effective measures here: clear all food off the boat, including packaged items such as pasta or chocolate bars. Also, don't leave any mooring lines hanging on the floor. This would be a welcome route for the rodents. Once they have settled on board, they will also destroy cushions (material for nest building). Therefore, remove food sources and access points. If mice have made it on board, only traps will help. There are different variants here.
Mosquitoes and wasps
Especially in light winds and close to the shore, the bloodsuckers can bring the most beautiful evening to an abrupt end. Escaping below deck can help, but with the bulkheads and hatches closed, it quickly becomes unbearably warm in summer - a horror. In most cases, the annoyance of the unpleasant evening doesn't stop there; the itchy bites can still bother you the next day. The first thing that comes to mind as an antidote is sprays such as Autan and the like. They are not only effective against mosquitoes, but also other biting insects and even ticks. Sprayed onto the skin, a special fragrance repels the bloodsuckers and the protection lasts for several hours. The so-called repellents often contain Icaridin (Autan) or DEET (Anti Brumm). The latter has a reputation for being more effective, but DEET (diethyltoluamide) can cause skin irritation. It is therefore recommended for tropical regions.
- Read our special article here "How to protect yourself from mosquitoes in summer".
In the Mediterranean or the Caribbean, there are mosquitoes that can transmit malaria or dengue fever. Therefore, the benefits clearly outweigh the possible side effects. In the North and Baltic Sea region, there have been no known transmissions of dangerous viral diseases through mosquito bites. However, this issue may become more important in Northern Europe in the future as a result of climate change. There are also essential oils, for example from the tea tree, which are said to have an insect repellent effect. Like other repellents, they also target the mosquitoes' sense of smell. They are particularly attracted by the carbon dioxide in the exhaled air and decomposition products from body sweat. If these odours are masked by flavours that mosquitoes don't like, this can mean the difference between a pleasant sundowner in the cockpit or completely stung legs. Experts therefore recommend a shower to wash off the sweat.
In general, sun protection should not be forgotten when using mosquito sprays. The correct order: first apply the sun cream; after this has been absorbed, apply the mosquito spray.
Nets for the companionway and hatches are very effective. Large mosquito nets can also be used to create a mosquito-free zone in the cockpit. Nets also help against wasps.
Spiders
Spiders are not pests, on the contrary, pests such as mosquitoes and flies are their prey. Nevertheless, spiders are usually not welcome. Their webs are particularly annoying and can block the clicker, for example. Owners of dinghies or daysailers who protect their boat with a full tarpaulin are particularly affected. This provides ideal conditions for spiders, which crawl out in large numbers every time the tarpaulin is removed. Below deck on yachts there are usually no problems if all hatches are closed while the boat is unoccupied in the harbour. To prevent spiders in the rigging or under a tarpaulin, there are sprays designed to keep spiders away.
- Click here for our special article "What to do about spiders on board? Test anti-spider spray, spider traps"
