Safe Wave Height knowledge for your small boat is needed before you even consider venturing out. Every year people have close calls, or even capsize, on Port Phillip Bay in their boat. Sometimes lives are lost. Hence this Port Phillip Bay Wave Heights Safe Boating guide is offered as a heads-up before you venture out.

Note it is only a guide to safe wave heights. Nobody can know your specific boat or how it handles it. Always leave a margin of safety. Port Phillip Bay is notorious for sudden weather changes, quick squalls and some very extreme conditions.

Note it is only a guide to safe wave heights. Nobody can know your specific boat or how it handles it. Always leave a margin of safety. Port Phillip Bay is notorious for sudden weather changes, quick squalls and some very extreme conditions.

Remember to ensure you are carrying the required safety gear in working condition. You can find out more about the legal safety equipment here.


Forecasted Safe Wave Height Caution

It’s easy, as a beginner, to underestimate safe wave heights:

  • A 1-meter wave can swamp a small boat.
  • The distance between waves is critical too.
  • Also always keep in mind that forecasted winds and waves are average.
  • Winds can be 40% higher than forecasted and wave heights will increase accordingly.
  • Port Phillip Bay conditions can change suddenly, sometimes with little warning.
  • Port Phillip Bay water temperature can kill, very quickly, between March & November.
  • Limit hypothermia. Dress for possible immersion. Wear correctly rated clothing. Not wool or cotton.
  • Carry and monitor phone or radio for weather warnings.
  • Carry an EPRB or PLB.
💡 Life Jackets – They Are The Law

Note – a point that cannot be emphasised enough. Wearing a properly rated lifejacket is not optional on most small vessels. It’s the law. Only a complete fool ventures out in a small craft without a lifejacket.

Check the Victorian legal requirements to find out what your boat requires here.

Keep in mind that Port Phillip Bay, in particular, has more in common to a large shallow lake than a traditional “bay.”

This is due to the very narrow neck (Port Phillip Heads) and the fact that it is a drowned estuary. The Yarra channel ran to the heads, by some accounts less than 8000 years ago. Flooding possibly after a storm surge damaging the area where the heads are now.

This is why it is both shallow and narrow at the entrance to the Bass Strait.

These conditions make for dangerous boating at times and is why a great deal of care and attention to forecasts must be undertaken.

It is the shallowness that makes your knowledge and respect for safe wave heights absolutely essential. Western Port bay being equally capable of becoming dangerous quite quickly too.

Staying within the recommend safe wave heights for your vessel is a step towards safer boating. A step towards not becoming another recreational statistic.

Planning your trips using the weather forecast, choosing safe wave heights for your vessel and checking the forecast regularly while out boating is not optional. It’s essential.


Boats 3.5m (12 feet)

👎   Wave Height 1.0 meters & Above
Dangerous.

At this wave height, you’re going to struggle in a boat of this size. Combine this with a strong on-shore wind and getting back to the ramp is going to be extremely difficult. Water is going to come on board – a lot of water!

This is considered the maximum safe limit for a boat of this size and leaves no room for an unexpected peak wave that are common enough on Port Phillip Bay to be a concern.

This is NOT a safe wave height for this vessel.

Don’t risk it. No fish is worth your life!

👎   Waves 0.8 meters & Above
Potentially Dangerous.

Your speed will need to be reduced significantly in order to be safe. Water is going to come on board at this height. You will need to take the utmost care. Keep in mind some peak waves may be over one meter in these conditions.

This is NOT a safe wave height for this vessel.

Take winds into consideration. Especially on-shore winds as these can make returning back to the ramp more difficult.

I wouldn’t risk it. In these conditions stick to estuaries, inland lakes and streams.

👎   Waves 0.5 meters
Caution Required.

At 0.5m you are still going to have to proceed at slower speeds. You will experience some pounding on the hull.

This is MAY NOT a safe wave height for this vessel.

Keep an eye out for strong on-shore winds. These can make returning back to the boat ramp more difficult.

I still am hesitant taking a craft this size out on Port Phillip or Western Port Bay in these conditions.

👍   Waves 0.2 meters
Ideal Conditions.

Waves will gently patter upon the hull. Water should not come on board. No spray should be present.

This should present pretty comfortable conditions for a boat of this size.

This is considered to be a safe wave height for this vessel.

Keep an eye out for weather changes – and plan to be off the water before a change comes through.

Remember the golden rule. Wave heights often peak above the forecast and conditions can change rapidly. Often in minutes. A Safe Wave Height can change suddenly. Do not get complacent.

Boats 4.3m (14.1 feet)

👎   Waves 1.5 metres & Above
Dangerous.

You are going to really have to be very experienced to even consider taking a boat of this size out in these conditions.

There’s going to be a lot of water thrown aboard, much of it heavy.

This is NOT a safe wave height for this vessel.

Take it really slow.

👎   Waves 1.2 metres & Above
Dangerous.

Make sure you pull that throttle right off. Slow and steady. You’re going to get wet because there’s going to be lots of spray coming in.

This is NOT a safe wave height for this vessel.

Really scary – rightly fully so – for average boaties.

Take it really slow.

👎   Waves 1.0 metres
Caution, Dangerous.

You’re going to get water on the deck. A fair bit of spray. Keep the speed down.

Keep an eye on the onshore winds.

This is NOT a safe wave height for this vessel.

Not really suitable for newbies or weekend warrior fishos.

👎   Waves 0.8 metres
Caution.

You should keep your speed reduced.

There’s going to be some pounding on the hull.

Some spray is going to be taken aboard your boat.

This is NOT considered a safe wave height for this vessel.

👍   0.5 metres Waves
Good Conditions.

Spray shouldn’t be there to bother you, just a gentle patter of water on your hull.

Spray shouldn’t be there to bother you, just a gentle patter of water on your hull.

This is good, reasonably comfortable conditions for a vessel this size.

This is considered a safe wave height for this vessel.

As always, keep an eye on the weather bulletins and updates.

👍   Waves 0.2 metres
Ideal Conditions.

Spray shouldn’t be there to bother you, just a gentle patter of water on your hull.

Pretty close to perfect conditions. Great to be out on your boat!

Great to be out on your boat!

This is considered a safe wave height for this vessel.

Keep an eye on the weather updates, make sure no changes are expected.

Boats 5 metres (16.4 feet)

👎   Waves 1.8 metres
Dangerous.

This is the limit considered safe to operate a vessel this size with passenger comfort.

Really scary – rightly fully so – for average boaties.

This is NOT a safe wave height for this vessel.

Experienced master advised. Keep in mind wave swells on Port Phillip Bay can be higher than the forecast average.

👎   Waves 1.5 metres
Potentially Dangerous.

Tackle each wave individually while steering, using throttle at all times is best.

Expect lots of spray and some waves can be expected to break over the deck.

This is NOT a safe wave height for this vessel.

An active eye on forecast bulletins is advised.

👎   Waves 1.2 metres
Caution.

Keep your speed down to slow speeds.

Expect a lot of spray on board with waves breaking over decks.

This is NOT an ideal wave height for this vessel.

👎   Waves 1.0 metres
Caution.

Keep at or below half-speed.

Expect some spray and green seas to come aboard.

This is NOT an ideal wave height for this vessel.

Keep alert and aware of forecast bulletins.

👍   Waves 0.8 metres
Fair Conditions.

Keep the speed down is best.

You will experience some moderate pounding on the hull.

This is Considered to be the MAXIUM IDEAL safe wave height for this vessel.

Possibly some spray.

👍   Waves 0.5 metres
Good Conditions.

Set throttle for cruising.

There’ll be some slight bumps.

This is Considered to be a safe wave height for this vessel.

Most of the spray will be thrown clear

👍   Waves 0.2 metres
Excellent Conditions.

Like sitting in an armchair.

Next to perfect conditions.

This is Considered to be a safe wave height for this vessel.

As always keep an eye on forecast broadcasts.

Otherwise, enjoy smooth sailing!

Boats 6 metres (19 Feet)

👎   Waves 2.0 metres & Above
Dangerous.

Keep it slow and steady.

Recommended for experienced boaties only.

This is NOT a safe wave height for this vessel.

You’re going to get some water breaking onto the decks at times.

👎   Waves 1.8 metres
Caution.

Keep the speed down.

Tackle waves individually.

You are going to cop a lot of spray.

There’s going to be water over your foredeck.

This is NOT considered a Safe Wave Height for this sized vessel.

👎   Waves 1.5 metres
Caution.

Keep the speed down.

Tackle waves individually.

Lots of Spray.

Water on your foredeck.

This is NOT considered a Safe Wave Height for this sized vessel.

👎   Waves 1.2 metres
Caution.

Keep speed to half.

You’re going to get a fair bit of spray.

Some water on your foredeck.

This is NOT considered to be a Safe Wave Height for this sized vessel.

👍   Waves 1.0 metres
Fair Conditions.

Slightly reduce your speed.

This is Considered to be a safe wave height for this vessel.

As always keep an eye on forecast broadcasts.

👍   Waves 0.8 metres
Fair Conditions.

Keep speeds down.

Some pounding on your hull is going to be experienced.

This is Considered to be a safe wave height for this vessel.

As always keep an eye on forecast broadcasts.

👍   Waves 0.5 metres
Excellent Conditions.

Maximum cruising speed on your throttle.

You’ll probably experience some slight pounding on your hull.

This is Considered to be a safe wave height for this vessel.

As always keep an eye on forecast broadcasts.

👍   Waves 0.2 metres
Perfect Conditions.

Things feel awesome.

Smooth ride.

This is Considered to be a safe wave height for this vessel.

Almost “glass” conditions.

The Wind Direction Plays A Role On Our Bays

The wind direction plays a role on Port Phillip and Western Port Bays, too.

For example, when the wind is blowing “onshore” from the west at places like Geelong, Werribee etc the wave height can be reduced significantly from the average. Whereas on the opposite side of the bay at Mordialloc, Frankston or Dromana it can be very choppy at the same time.

This is because the direction of the wind goes against (lower chop) and with (higher chop) respectively in the example.

As always – don’t use this as the single determining factor. Conditions should always be checked in advance – and monitored at all times!!

Download Wave Height Guide

Download Wave Height Guide

Download Safety Fact Sheet

Download Safety Fact Sheet

Lifejacket Videos

Safe Boat Wave Height Table

Wave Height In MetersBoats 3.5m (12 Feet)Boats 4.3m (14.1 feet)Boats 5m (16.4 feet)Boats 6m (19 feet)
2 MetersNEVERNEVERNEVERDANGEROUS
1.8 MetersNEVERNEVERNEVERCAUTION
1.5 MetersNEVERDANGEROUSDANGEROUSCAUTION
1.2 MetersNEVERDANGEROUSCAUTIONCAUTION
1 MetersDANGEROUSCAUTIONCAUTIONSAFE
0.8 MetersDANGEROUSCAUTIONSAFESAFE
0.5 MetersCAUTIONSAFESAFESAFE
0.2 MetersSAFESAFESAFESAFE

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