Wave height...??

There are a lot of people who don't go out over 3 or 4' measured top to bottom, peak to valley, distance above mean to distance below. We find we go out regularly in conditions that others don't.

Yeah, but you don't go far in the waves you have usually, if you want to fish you run 5 miles.

Different story if you plan on running 200 nm a day in it and for 8-10 hours....... Also wave period and direction is huge in regards to ride quality.

I'm leaving tomorrow with a 62' motoryacht express for Nassau 160 NMs.....boat cruises 28 knots......2-3' on the way over.......Supposed to come back on Monday but calling for 4-6' seas and occassional 9' seas. I'm NOT coming back in that...The boat will take it, I'll take it....but not worth breaking a bunch of stuff on the yacht........I have the owner and his wife......SIL and daughter late 30's and 4 kids under 11 years old. Not going to happen...won't even attempt it with the kids that age....their second yacht trip and I'm not going to scar them for life......so will either wait and fly them home.....or hope the forecast (which doesn't make sense compared to the wind) changes by then.

We are heading over to Lucaya Sunday morning and then onto the Abacos, then Harbour Island, Atlantis, and the Exumas for 6 a week trip. I have been watching the weather closely in preparation and it is a bit of a strange weather system for June with a large swell coming down from activity in the North Atlantic that will push into the gulf stream Sunday night. It is the combination of local wind waves and a strong distant northern swell that will make Monday unpleasant.

I want to share a new web site access from NOAA that I am really happy with and are now using and find to be by far the best. I have always been happy with passageweather and their graphics, but now realize that I think they are getting their data from the environmental modeling center at NOAA and the NOAA Wavewatch III product viewer. The Wavewatch III gives full access to the ensemble models being used to generate the marine forecasts by NOAA. You can independently access wave heights, winds, wind waves, distant swell etc. with 7 day forecast modeling and really piece together a better understanding of the current and near future waves. It is by far the most comprehensive and in depth tool I have used. Try looking at the east coast global model.

I'd rather put 10 hours in on the ditch than 8 hours in a sea. Can walk around, grill lunch during long slow speed zones. A little more concentration, but more scenery to look at, but less wear and tear on your body. I do A LOT of miles each year on deliveries, it's tough on your body, and quite frankly have a lot of aches if it's rough......all manageable, but I'm not taking a 50' MY out in 6' seas for the day by choice..... a 50' SF sure.

Depends on the size of the boat. A 50' MY and you can run at cruise most places in the ICW . I've done Jekyll Island to New Smyrna in a short winter day and New Smyrna to Jupiter in a day in December and the boat only cruises at 21 knots. That being said the boat is range short and 170 NM MAX, and on the way to Baltimore from Key West, only days on the ICW were Southport to Wrightsville Beach (20NM) and Beaufort, NC to Norfolk by choice. We also did Fernandina to Jekyll, wife jumped on then did Hilton Head and then Charleston on the inside, she jumped off and we jumped outside again. Just got home from that 1200 NM trip last Sunday and leaving for Nassau tomorrow and back possibly Monday.

Monday is calling for occassional 9' with a 10 second period so sounds like swells we can run at least 24 knots in if 29 is too much...... I only have fuel to run 8 hours at cruise MAX in this boat, but Nassau is 5 1/2 port to port, so the speed makes for shorter days and if you do 7 hours or so at cruise at least you're getting somewhere.

Wavewatch III has been around a very long time. I used to use it a lot 10 years ago or so. Very few people know about it for whatever reason.

Wave period must be taken into account. A 4' height with an 8 second period is very different from a 4' wave with a 3-4 second period. Also keep in mind that waves are not uniform, so while the reported dominant wave height might be 4', there are going to be 6-8 footers in there as well.

I don't see any confusion. First, the definitions. Wave height is the distance between the trough and the adjacent crest. What is reported in forecasts is "significant wave height." That is a measurement of the average of the highest 1/3 of the waves over a given period of time. That's simply a method of smoothing. In the course of a 24 hour period the tallest wave may be as much as twice the significant wave height.

Every forecasting service I'm aware of uses these rules.

Now, remember these are forecasts. Actual is then reported by buoy measurement or other means after. Like any weather forecasts, there is error.

The variation between forecasts has nothing to do with the meaning of wave height, but is simply different forecasts.

As to what one personally considers too high for getting out, depends on boat, on reason for traveling, on tolerance and comfort for conditions, on experience of crew, on distance to be covered, on confidence in the forecast, on possible means of escape if conditions worsen.

It makes perfect sense that with us covering 17,000 to 20,000 miles a year and boating over 1,000 hours a year, we'll be comfortable getting out in conditions someone boating 50 hours a year would not. Commercial ships would be inclined to get out when we wouldn't as they have more experience, bigger boats, and aren't concerned with comfort of guests.

We judge height and period together. We look at wind waves and swell. We boat for pleasure so ultimately if we believe it's going to not be pleasurable, we don't go. Again, that differs for different people. I know people who consider 4' at 6 seconds to not be pleasurable. We consider it fine. Length and speed of boat factor in. They determine how many times in a minute I'm going to go up and down.

Surprisingly, I've seen those who travel at displacement speed in trawler type boats often the ones who will get out in the least. (Contrary to the small number of them who cross oceans). It sounds illogical until you understand. First, many of those do the majority of their cruising in the ICW. They have no experience in rough conditions. They haven't practiced in rough seas or developed knowledge or skills. Second, they have no ability to pick the best speed as they have one speed and one speed only. Nor can they vary direction significantly as taking a slightly different direction adds hours to their trip time and could quickly double it. Third, many of their boats lack stabilizers. Fourth, many of their boats do not handle waves from some directions well at all and can't adjust speed to do so better. Fifth, their boats are often least equipped to go out of inlets and to return into inlets. Sixth, they are going into the wave getting the greatest of it's force. They lack the ability to get on top. And they are getting every single wave as opposed to a boat on top that might go from crest to crest.

The OP is use to his area and comfortable with it and thinks nothing of it. the PNW was new to us. 10' waves sounded large at first until you realized they were 10' at 13 second swells. However, the bars/inlets were the challenge in those areas and small displacement speed boats could easily lose control to the waves through them.

Then there are personal preferences. Many prefer the ICW. Capt J likes it sometimes. We avoid it as much as possible, only using it when outside conditions force us. And then it's who is aboard. The majority of people who travel with us are seasoned boaters and experienced and use to less than ideal conditions. Were we taking first time boaters out we'd be far more selective. Were we taking children far more. Size of crew plays a role. Today we have 9 of us on board. 4 of us are licensed captains, one an engineer, 2 others have some experience handling boats and the other 2 have experience as crew on a boat. If I was the only experienced operators with 8 friends with no experience along for the first time, it would be far different.

I consider how long we'll be in less than ideal conditions and what happens if they worsen. If I'm on a 6 knot boat crossing from Nassau to Fort Lauderdale, then if it's uncomfortable it is so for a long time plus conditions can change radically in the time it takes me to cross. Plus I know the gulf stream will be worse than what I'm seeing starting out. If I'm cruising at 25 knots I'm looking at a very short window. I could also quickly change course for Bimini if conditions ahead and in the gulf stream were turning much worse very quickly. Still, if I know tomorrow is going to be much nicer, I'll choose to enjoy today at Atlantis.

One man's trash is another man's treasure