Yeah about 10-15 knots (roughly 28 kmh winds) is maximum in my 4.85 metre tinny..after that it's no longer FUN and I assume that is what we all want to have.
Of course if you have a 6m+ then you could probably settle for more like 20 knots?
Really its what you are willing to put up with

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I find Bom to be the most acurate but as cuddlescooper said, i look at a few sites and just get an general idea of calm, choppy or cr.p. in my 4.5 tinnie 8 to 13 is ok for fishing in open water, 10 to 15 is probably limit for open water but ok for traveling to a protected spot and ill only go 13 to 18 if I can hug the coast most or all of the way to a spot. 15 to 20 is good for the pub...

Hello Matt

A good rule of thumb is if u look at the water and have to look again to think about it, then don't go.

U're talking offshore.

Wind speed is only 1 of the factors. The other is swell.

Waves are caused by local winds.

Existing swell is caused by wind activities a long way away at times or a storm a day or 2 ago.

Swell and wave combine to give the height of the seas u will be dealing with.

A 15 knt (28 km/hr) wind will probably produce 1 - 1.2m waves if they have been blowing over open water for any distance (called fetch).

If the sea has an existing 2m swell u add the wave (when it reinforces the swell) and get 3.2m (2 metre swell with a 1.2m chop on the top). That's a worst case scenario but it happens.

Best case scenario is when the swell and the chop oppose u end up with .8 metre.

So apart from what is the wind doing, what is the swell doing too?

I wouldn't like to be out there in a 5m boat in up to 3.2 metres of trouble.

Imagine a 2m swell from 1 direction, a 15kt wind from another and a tide partially opposing both. What would the sea look like with those different directions involved.

Little numbers can add up to big trouble in small boats offshore.

Convert knots to km/hr by doubling it and take off 10%.

Swell AND wind.

Attached is a copy of the Beaufort scale with photos of waves caused by various wind speeds. Some of the stuff looks good from high on the ship's deck but in a small boat its completely different.

All boats seem to lose about a third of their size when taken off the trailer and put in the water.

[quote="ronje"]Hello Matt


Best case scenario is when the swell and the chop oppose u end up with .8 metre. (quote)


I know you have a mountain more experience than me Ron even extending to rescues etc but I have never heard of this type of thing. Is it somthing that marginally improves a very bad sea state maybe I have seen some shocking seas when you get wide enough to have a strong offshore wind on a decent swell (East Coast that is). The other factor is that it is very common that people over estimate the wind speed they are experiencing in my experiencing once it gets to 15-18 knts or so. That beuford scale with photos is a very good tool and full size veiwing of the poster should be manditory.

Hi Andy

I was referring to a wave train with certain distances between peaks (periods) and a swell train with different distances between peaks.

In retrospect, I don't think I did it very well. Perhaps I should have used the term "in sync".

For periods when the peaks are in sych, u can have a trough to peak height of 3.2 metres. For periods when they don't, you have a swell height of 2 metres and halfway between the swell peaks u have a wave peak of 1.2m giving an apparent sea height of .8m below the level of the swell peak. If the wave peak is just behind the swell peak the top of the swell will have a fairly wide "plateau" of calmer water (until the synch drifts again).

Depending on how far out of sync the wave trains are, the ride up the approaching combined front can be smooth with the ride down the back pretty scary (or even non existant)i n a small boat.

If u're travelling in the same direction as the waves and swell, u can get into some broaching situations easily if u're not careful. If the set of waves/swell u're riding are just out of snch, you can get a pretty smooth ride for a while before the sych gradually changes. Then its best to drop off the back and wait for the sych to become favourable again. Bit like surfing I guess.

Had to transfer a paramedic onto a trawler in seas a bit bigger than that and then take him and the injured party off 15 minutes minutes later. Bit scary waiting for the wave/swell sets to drift into the right sync and then bump the reinforced bows of the big cat onto the trawlers stern. For about 30 secs the boats were the same height and in the same patch of water touching each other with both people simply stepping from the trawler onto the bow of the cat.

That was what I was referring to as opposing. Wrong set of words.

Anyway, the important thing for Matt is to take notice of swell in offshore waters.

Good points all.
One thing that can catch you out is you look at the water and it’s a glass-off. So you poke out a bit further than you would normally.
The breeze pops up and you think, ‘just one more’ and the next thing you know you are pushing back into a sloppy mess that can get very scary in a little boat

Thanks Ron makes a bit more sence now.

Thanks Ron makes a bit more sence now.

Great 2 in a row.

Twice as much sense then!

Yes I guess that would be right.

One thing I watch closely is the run of the tide. If the tide is running against the wind the waves stand up. If it's running with the wind it flattens out. As one skipper said, "The size is not so much important as the shape. That goes for a lot of things in life." If you're heading to say Charles Pt where the tide rips over shallow ground on a spring tide and it's against the wind then watch out. Sometimes when it's ugly you just need to wait for the tide to slacken.

All I can say on this is Boat size and ability,ronge has hit the nail on head,,,,swell can be the scary factor as the weatherman says "winds and waves can be 40% stronger than forecast here" .Just check the Bom and orther sites ,I find the bouy weather the best for seeing whats going on outside.
At the end of the day Matt no fish is worth a swim, or a Life,,,,,,,,,

Cheers
Jeff

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