Is there a rule of thumb you use for rough seas?

[Chinookie]

First, I possess little knowledge of seamanship. Eight years ago I ventured out with my son in a Northriver Seahawk, leaving La Push in a easterly wind. Midway to a halibut spot I had never been to a Coast guard rescue craft flew by me with lights flashing. I decided to turn back, as that looked to be a bad omen. Immediately two things happened. First, we began taking green waves over the bow, and then the bilge pump chose that exact moment to die. I quickly learned, with no prior knowledge, how to throttle back so as not to stuff the bow quite so bad. I never took that boat to the ocean again, because those tiny drain ports on the bow are useless with a stuffed bow.
Now I own a Grady 228, a very different boat, but a small boat nonetheless. I would like to know if there is a simple formula I can use to keep myself alive when planning. Something like wind waves plus swell never more than X1 when period is Y1 and X2 when period is Y2. Even if you don't own a 228 I could benefit from your personal maximums.
I have begun to study some, and last nights read was on the perils of following seas, and how to stay on the wave with throttle mgmt, but I have much to learn. Especially on the matter of knowing when it's better to go out to sea to stay alive when trying to go back.

The best seamanship is to plan not to be on rough water, but sometimes nature makes new plans. If anyone knows of some good on line reference material I will be grateful.

 

[Late Again Grady]

Wave period three times wave height or more. Not familiar with the west coast but that rule should keep ya safe. Anything over three feet in height, I'd stay nearshore.

 

[Mustang65fbk]

I mean... my personal thoughts on the matter, and without any sort of mathematics into the equation, would be... "am I going to be able to fish by myself? and is this going to be fun?" As mentioned, I typically go out fishing alone, or maybe with one or two other people at the most, but if the winds are 15+ mph or more, it's going to make for some rough fishing with downriggers and trolling for salmon, etc. In which I usually look out at the water from my beach cabin and ask myself the two questions I asked above of "am I going to be able to fish by myself? and is this going to be fun?" If the answer to either of those questions is "no", then I'll typically just go back to bed for a couple of hours, wait until later on in the afternoon to see if the conditions change, as I don't want to be out in them especially if it's going to potentially get worse, etc.

 

[Chinookie]

Thanks for your reply. This is where I get confused. There can be wind waves that are typically short spaced, and then there are swells, which are also spaced, sometimes long sometimes short. I think there can be both at the same time, no? If so, how do I apply the period rule of 3 and does it apply to the waves or the swell, or both? Am I making this too hard?

 

[kirk a]

Rules of thumb are a starting point. Combine those with local experience, and you'll quickly figure it out.

For swells, I like the ratio to be at least 2-1. So for a 3'sea, I'm looking for at least a 6 second period.

Wind chop is different. I boat in a location notorious for wind against tide - Buzzards Bay MA. A NE or SW wind over 15 can be problematic or even deadly with the wrong tide. Even in a 33, fishing in 15kt wind is not fun and relaxing when the fetch is long.

 

[Ekea]

im a 1:2 crowd. if the wave height in feet is half or less than the period in seconds, its good enough. a long ground swell shouldnt bother you too much. if the swells get steep enough to break, you dont want to be out for that.