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Double rules
 

Collision Advoidance Mnemonics

Collision advoidance for sailing vessels can be a difficult area of the Collision Regulations to master and some ideas are presented below.

See also my Flash movie on the subject.

Double Rules

Give Way sign.If you are on a sailing vessel, imagine that there is a "Give Way" sign stuck to the starboard cockpit seat. This will help you in deciding whether to give way or stand on. It works like this:

If you spot another vessel and it is above you in the "Give Way hierarchy", (eg. a fishing vessel or sailing whilst you are motoring, you give way whatever. If it is below you (it is powered while you are sailing, you stand on whatever. But if it has the same level, you make a decision (partially) based on this sign.

Both Motoring

If you see the vessel off your starboard side, you will also see the Give Way sign, so you give way. If you see it off to port, you will not be seeing the Give Way sign, so you stand on.

Both Sailing

If you are on port tack, you (the helmsman) will be sitting on the port side, with your back against the wind. If you see a vessel to starboard, the sign tells you to Give Way. Either the other vessel will be on starboard tack (so takes precedence), or port tack but to leeward so you again give way.

If you are on starboard tack and a vessel appears to starboard, you cannot see the Give Way sign (since you are sitting on the starboard side and it is hidden beneath your back), so you do not give way (you stand on). If it is also on starboard tack, it is to windward so you have precedence. If it is port tack, you also have precedence.

Unfortunately there is no easy rule when a vessel appears to port. The only "rule" I can come up with is:

Give way sign port

 

Port viewThis could be turned into a mnemonic by imagining a "Give Way" sign on the back of the other vessel's helmsman. If you can see it, he is on starboard tack and you would give way, either because you are on port tack or you are to windward. If you can't see it, he is on port tack so you stand to, either because you are on starboard tack or he is to windward.

 

The only problem with these signs is if either vessel is using a wheel or self-steering, or the helmsman is inconsiderately sitting with his face to the wind. In that case, imagine the second Give Way sign on the back of the vessel's sail rather than the helmsman.

 

Double Rules

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