The International Regulations for the Prevention of Collision at Sea (or IRPCS) are rules that apply to all vessels using the sea, whether commercial, leisure, UK-flagged or otherwise. These rules are similar to the rules of the road for cars in that they help prevent collisions and ensure that everyone can coexist safely on the water.

One of the most important aspects of boating is to be aware of other vessels around you. This includes knowing who has the right of way in various situations and what to do when things don’t seem to be going how you expect.

Regardless of the rules, anyone using the water should be vigilant and keep watch. Remember, you’re not just responsible for keeping yourself and your crew safe; you’re also responsible for ensuring the safety of other vessels that might be nearby.

Big or small, power or sail, knowing the rules of the water is the best way to stay safe at sea. Photo credit: Danniel Corbit


“Stand on” vs “Give Way” (driving on the right side of the ‘road’)


If you’ve been researching the boating rules of the road, you might see mention of “Stand On” vs “Give Way” vessels. This sounds complicated, but it’s really just telling you who has the right of way when two vessels are approaching one another.

When boating, irrespective of what type of boat you’re on, the “Stand On” vessel is the one that has the right of way and should maintain its course and speed when approached by another boat. The “Give Way” vessel has responsibility for taking the appropriate action to avoid a collision.

Multiple circumstances dictate the boating right-of-way rules, which we’ll discuss in the rest of this article, but a good guideline is simply to consider who can get out of the way the fastest. For example, “power gives way to sail” is correct unless the power in question has restricted movement (perhaps due to draft or it is cumbersome to change course).

In other words, if you can more easily move out of the way (particularly if the approaching boat is the larger vessel), you should.

Port and Starboard


Before we go into too much detail about the boating rules of the road, it’s important to remember your port and starboard. When facing the bow of your boat, the port is to your left, and the starboard is to your right.

Port and starboard are important as they never change and always refer to the left- or right-hand side of the vessel, no matter which direction you or your crew are facing. Think of it like referring to the ‘passenger’ or ‘driver’ side of the car. It doesn’t matter where you’re sitting in the car; the titles for each side never change.

It may also be worth mentioning that port and starboard have their own colours, which makes it easy to stick to the correct side of a buoyed channel or figure out which side of a boat is approaching you at night. Starboard is always green, and port is red.

A wooden boat on a red and green background indicating which sides are port and starboard

No matter which way you look at it, port and starboard never change sides. Photo credit: Pippa Shaw



Check out our beginners' guide to common boat terms for more boating terminology.

Direction of travel


When operating a boat in a river or buoyed channel with vessels travelling in both directions, you should always keep to the right-hand side of the ‘road’ so that you pass oncoming traffic port to port.
In other words, always drive on the starboard side.

Overtaking


When a vessel wishes to overtake another, the overtaking boat will be the Give Way vessel and must keep clear of the boat it’s overtaking. The boat being overtaken is the Stand On vessel and should maintain its course and speed, letting the Give Way/overtaking vessel make the manoeuvre.

Boats may overtake on either side (when it is safe to do so, keeping an appropriate distance from the Stand On vessel), but where possible, the Give Way (overtaking) vessel should pass on the port. This is because the Stand On vessel should already be as far over to starboard as possible.

Approaching another boat head-on


When you’re not in any sort of channel, you would be forgiven for thinking that the rules of the water don’t apply. But just because you’ve got the whole ocean to play in, doesn’t mean you won’t end up approaching another boat head-on. In this instance, both vessels are responsible for avoiding a collision and, where possible, should alter their course to the starboard so that the ships pass port-to-port – like you would in a river!

It’s essential to make the required adjustment to your course early. You should also make it clear to the other vessel that you have done this, so an exaggerated turn to starboard may be required to ensure they’re fully aware of the action you’re taking.

Occasionally, there will be times when one of the boats approaching head-on cannot make the required course adjustment. This is where the further rules about power giving way to sail, and the ease of movement come into play.

Collision course – power meets power


When two powerboats meet on the water head-on, the above rule applies, and both vessels should alter their course to the starboard in order to pass port-to-port and avoid a collision.

When meeting at an angle, a boat coming from your starboard (right) will be the Stand On vessel, and you should move clearly to starboard and pass behind them. If the boat is approaching from your port (left), it becomes the Give Way vessel, meaning that you have the right of way, and they should make the necessary course adjustments.

If you are the Stand On vessel and the Give Way vessel doesn’t appear to be altering its course, the first thing you should do is slow down to give them more chance to spot you and move to starboard. If they are still not moving, you must turn your own vessel to the starboard to avoid the collision. Do not turn to port, as this can complicate the manoeuvre if the Give Way vessel has turned or turns late. Always keep as much distance between yourself and an approaching vessel as possible.

Collision course – sail meets sail


While the rules of giving way by turning to starboard are a good baseline, things can get a little more complicated when two sailboats meet. In these circumstances, it’s all about keeping the wind in the sails and ensuring that both vessels can continue operating safely.

Here are some guidelines for who must give way when two sailing boats meet:

  1. Port gives way to starboard: A vessel on a starboard tack has the right of way (Stand On) against an oncoming vessel on a port tack (Give Way).

  2. Windward gives way to leeward: When both boats have the wind on the same side of their boat, the windward (upwind) boat is the Give Way vessel, while the leeward (downwind) boat is the Stand On. This is because the windward vessel is the most manoeuvrable.

  3. Unsure port: If you’re sailing on a port tack and can’t determine the wind angle on an approaching vessel, you should assume the other boat is the Stand On vessel and give way accordingly.

  4. Restricted vessels: Any sailboat, regardless of tack, must give way to vessels that are not under command, are restricted by ability to manoeuvre or draught, vessels that are fishing, or mine sweepers.


Under bridges


When cruising under bridges, there may be reduced space, and it may not be possible for oncoming vessels to pass port-to-port or even stick to the starboard. Therefore, irrespective of the direction of travel, the boat closest to the bridge will always have the right of way and be the Stand On vessel. The boat furthest away should Give Way and keep to the starboard, allowing space for the other boat to pass safely.

Once the Stand On vessel has passed, the Give Way vessel may travel under the bridge.

A yellow canal boat is viewed through the arches of a bridge

When approaching to pass under a bridge, the boat closest to the bridge has the right of way. The Give Way vessel should wait to the starboard for the Stand On boat to pass safely before proceeding. Photo credit: Bradley Hebdon


On rivers


Generally, vessels operating on UK rivers should always travel on the starboard side and pass oncoming traffic port-to-port. However, where this is not possible, the boat travelling downstream will have the right of way.

“Power gives way to sail”


There is an adage that sailors often learn early and quote regularly… “power gives way to sail,”- implying that sailboats have the right of way in most circumstances. And while there’s an element of truth in this matter, boats under sail mustn’t get complacent and expect all other traffic to move out of the way, as there are some circumstances where the wind in your sails does not mean that you automatically become the Stand On vessel.

So, before you take your sailboat (or any other vessel) on the water, it’s important to learn the give-way hierarchy of boating:

  1. Power boats give way to sailing boats

  2. Sailing boats give way to vessels engaged in fishing

  3. Boats engaged in fishing give way to vessels with restricted ability to manoeuvre

  4. Vessels with restricted movement give way to vessels not under command.


It’s also important to remember that a sailboat with its engine on – even if it’s motor sailing – does not have priority over a power boat and should give way according to the boating rules of the road.

The four give way rules illustrated by different boat graphics

The adage “power gives way to sail” is really only the start of the story. In truth, sailboats are relatively low on the pecking order of boating priorities.


When things go wrong


I remember being told a story once of a sailor cruising along the sea when a large power boat became visible on the horizon. It became quickly evident that the two vessels were on a collision course, and one would need to move. As the boats drew closer, the sailboat's skipper radioed the larger ship, shouting, “Power gives way to sail, power gives way to sail!”. It took some time to receive a response, but when it came, it was an ominous warning: “No. Plastic gives way to steel.”

There are various reasons why the sailor was wrong in thinking they had the right of way in this instance (for one, calling it a ‘power boat’ is considerably downplaying the size of the approaching ship). Still, it also serves as an important reminder that even when you have the right of way, you can’t always assume that the Give Way vessel will, in fact, give way. And you should know what to do when others don’t follow the give-way hierarchy.

If you believe you are the Stand On vessel and the Give Way boat isn’t altering its course, you should immediately slow down and prepare to stop the boat if possible to give the Give Way vessel time to react. Then, you may alter your own course towards your starboard. You should make this move clearly so the other boat can see what you’re doing.

You can also radio the oncoming vessel to ask what their intentions are. Sometimes, the Give Way vessel may not be moving because it’s coming into a harbour or heading to a mooring buoy. Or, if it’s a larger vessel and you’re on a small boat, there may be a possibility that they haven’t seen you.

As with all evasive manoeuvres, it’s a good idea to attempt to make contact early and clearly to avoid misunderstandings. Most ships in UK waterways maintain a listening watch on channel 16, so you should be able to make contact here and then move to another channel to discuss the required manoeuvres.
If you don’t currently have a radio on board or would like a refresher on VHF radios, take a look at our VHF Radio Guide.

Whether you’re the Give Way or Stand On vessel, you should always try to avoid a collision by turning to starboard, never port.

Making waves


If your boat makes a wake/wave when moving, it’s essential to consider how this can affect other vessels, wildlife, and water users around you.

Therefore, if your boat makes a wake, it’s good boating etiquette to be aware of this and how it might affect other boats, swimmers, anglers, or shoreline owners around you.

Not only can a large, obtrusive wave cause considerable discomfort to others trying to enjoy the water, but they can even be dangerous to those unable to tolerate excessive wake. It can also disrupt local wildlife and can be a particular problem in conservation areas.

So, if your boat throws out a lot of waves, slow down and stay at least 200 feet away from the shoreline and other boaters.

Similarly, take note of whether the body of water you’re operating on has a speed limit or no-wake restriction. If it does, respect these rules and slow down.

(On the other hand, there are moments when those big wakes can be a lot of fun! Check out this video of an orca playing in the wake of a powerboat!)

Say hello


The final “rule” of boating is always acknowledge another boat. No matter the size, shape, sail or no-sail; anyone enjoying the water is part of the boating community. Keep it friendly, and always wave hello. You never know who you might befriend at your next port!

No matter what, the boaty wave is the height of boating etiquette to be disregarded at your own risk!

For more tips on safe sailing, read our article on avoiding hazardous waters and find out whether you need a boat licence for your vessel.

Written by: Pippa Shaw
Pippa is a freelance copy and content writer living on her 28-ft sailing yacht with her partner and boat cat, Opie. As a full-time liveaboard and digital nomad since 2019, Pippa’s got plenty of nautical miles and boat renovations under her belt and is currently completing a UK circumnavigation before setting her sights on warmer waters.
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