Environmental Guidance for Cruising Yachtsmen


One long standing objective in the Cruising Association’s Articles of Association is 'To promote the preservation and protection of harbours, navigational facilities, estuaries, coasts and their environs'.

Over the last half-century, there have been significant developments in reducing the environmental impact of cruising. Many boats are fitted with holding tanks; engines are more efficient with lower emissions; and we are more conscious of how our actions affect both our immediate surroundings and the wider oceans.

The CA’s approach is to communicate and encourage best practice and keep members informed of national and international legislation and initiatives.

This document is offered as a guide to current best practice. It was prepared with the help of our Regulatory & Technical Services Group (RATS) and other volunteers and will be updated as necessary.


One attraction of recreational cruising is involvement with maritime and coastal ecosystems. It is in our interest to protect and enhance them. We should:

  • Avoid disturbance of all marine species.
  • Avoid approaching bird colonies.
  • Avoid disturbance of the seabed by inconsiderate anchoring. Use fixed moorings if available and if they are suitable for the vessel.
  • Marine Protection Areas are increasingly common around the UK, and more are planned. Other maritime states have equivalents or are planning them. Such areas may not always be marked on charts. We should make sure we are aware of and comply with them.
  • Avoid introducing or spreading invasive species.
  • Avoid discharging water- or air-borne pollution into the marine environment.


We should minimise use of hydrocarbons and consider how we can reduce our carbon footprint. This helps slow climate change and encourages the development of cleaner technologies.


Sailing Boats

  • Sailing rather than motoring, wherever safe and feasible, reduces pollution and expense. The manufacture of sails uses artificial fibres which in many cases involve hydrocarbons, so consideration must be given to disposal and recycling of end of life sails.

Engines (auxiliary power on sailing boats and primary power on motorboats)

  • Most cruising boats are powered by diesel engines. Most would be difficult and expensive to convert to cleaner power. There is significant development taking place on alternative power sources but scrapping diesel engines within their useful life is not sustainable.
  • The aim should be to make diesel engines as efficient as possible. Correct maintenance, correct propellors and clean hulls increase fuel efficiency.
  • Reducing revs and speed can reduce fuel consumption and pollution. Every engine has an optimum combination of revs/speed for maximum fuel efficiency.
  • Boatbuilders are increasingly offering electric motors for new boats but this is not a realistic choice for cruising, other than day sailing from a marina with shore power for battery charging.
  • Battery capacity is the biggest issue against electric power. Batteries are big and relatively heavy, reducing sailing efficiency.
  • Hybrid power, which marries diesel power for battery charging with electric drive, could provide the autonomy needed for cruising.


The best choice is an electric outboard motor. The electric option avoids the risk of carrying petrol, and of spillage during refuelling. We should use hydrocarbon outboard motors as little as possible. Rowing is, of course, the best environmental option and provides good exercise where safe and feasible.

Electric Power Generation

  • Running the main engine to charge batteries creates carbon emissions, noise and odour. It may also reduce engine life and necessitate more frequent servicing. It should be avoided if possible. Dedicated diesel generators are more efficient and less polluting than using the main engine.
  • Solar panels, fuel cells, wind or water generators offer sustainable power generation.
  • We should recharge batteries from shore power when possible. Shore power generated from hydrocarbons produces about one-third the greenhouse gases created by onboard diesel generation. Shore power is also, increasingly, generated sustainably.
  • For normal electrical needs solar panels are economic and easily managed. They are rugged and capable of long life in the marine environment. Wind generators are well proven and sustainable. Water generators are mature technology and are popular for longer distance cruising.
  • We can reduce consumption in a number of ways such as fitting LED bulbs, increasing insulation of fridges and powering-off equipment like radar and depth sounders when it is not needed. An energy audit can determine what is using power, and how much it is consuming.


The most common source of energy for cooking aboard is bottled gas, a hydrocarbon. It can be replaced by electric power. This would not be sensible if the power was generated using the main engine or a diesel generator. When on shore power, one or a combination of a microwave, a radiant or induction electric hob and an electric oven produces much less greenhouse gas. Thermal cookers also reduce fuel consumption.


We have the facility to discharge sewage, grey water, bilge water and cleaning products into the aquatic environment. We must minimise the impact of such discharges.

  • Comply with or exceed international, national and local regulations about discharges afloat. Do not discharge into waters where there is poor circulation like rivers, lakes, canals, harbour basins, lagoons or otherwise environmentally sensitive areas.
  • Black water (sewage) is best kept aboard in a holding tank until pumped out at a shoreside facility for proper treatment. Where facilities are inadequate or non-existent cruisers should encourage marinas and harbour authorities to install them. If there is no suitable disposal facility, holding tanks should be discharged offshore in accordance with local regulations and by-laws.
  • Grey water (wastewater from galleys and showers) is a source of pollution due to the presence of cleaning products and waste particles. It is generally discharged straight overboard. Fitting a grey water holding tank is a solution and is already required in some countries. Be sure to use biodegradable washing and cleaning products. Where possible wash utensils and shower at shoreside facilities.
  • Bilge water can carry traces of oil, emulsions and particles including plastics and metals. There are filters which fit into bilge discharge pipes to remove these.


  • If we observe significant pollution on the water or ashore, material being discharged or dumping taking place we should report it to the appropriate authority, possibly by telephone rather than on an open radio channel.
  • When underway, we can recover floating debris for disposal ashore if it can be done so without putting ourselves or our crew in danger. Retrieving it is a good exercise in boat handling. An angler’s landing net is a useful addition to the boat’s inventory for this purpose.
  • We can also take a bag when walking the shoreline to collect any debris for proper disposal.



  • At home we are used to minimising waste and sorting recycling and we can do the same afloat, keeping separated waste aboard and disposing of it at designated shoreside facilities. Facilities vary by location: comply with local practice as far as possible.
  • Consumable stores are often robustly, even excessively, packaged. Repacking in reusable containers before taking it aboard helps leave much single-use packaging in proper facilities ashore.


  • Spillages when refuelling are not uncommon. Use absorbent spillage pads and bunds to contain spills.
  • Put absorbent material below the engine to catch leakage there and prevent contamination of bilge water. Dispose of spillage pads correctly ashore.


  • Waste generated working on boats, afloat or ashore, can be highly polluting – even toxic. We should separate different waste types and dispose of them carefully in the correct skips, or take them home for disposal if there are no suitable yard facilities. The most polluting items like waste oil, filters and batteries should be put in the correct disposal points. Some yards have separate bins/skips; others don’t. Pressure from customers can help improve yard facilities.
  • Boat maintenance uses a wide range of products. We should aim to minimise the use of high volatile organic compounds (VOC) paints, solvents, resins and cleaning products. Manufacturers increasingly provide equal or better performance from water-based products.
  • Antifouling is dangerous to the aqueous environment. Many yards have special facilities for removal of old, and application of new, antifouling. Where there are not, we should take care to capture and collect waste antifouling, old or new, as well as contaminated materials like brushes, rollers and overalls and dispose of them responsibly.

Use Recycled Materials

  • Many suppliers now use recycled materials in the manufacture of products as varied as cordage and clothing.


  • Glass reinforced plastic is not intrinsically polluting but air or waterborne fibres can be a health hazard to marine life while building and repair relies heavily on oil-based volatile organic compounds.
  • The development of alternatives to oil-based resins is moving fast. Some boat builders now use plant-based or partially plant-based resins.
  • Buying or building a new boat can be the opportunity to investigate less environmentally damaging construction materials and techniques.

The Green Blue

The Green Blue is a marine industry environmental awareness programme with a wider remit than cruising. Members can find it here: https://thegreenblue.org.uk

Version date: 09/12/2020