Seastates

[ccriders]

I've never sailed in the ocean or gulf, only bays and rivers. So how do I interpret the weather report that says seas 4 to 5 feet, six second period? I understand how to measure wave heights and periods, but what combination is comfortable for a 28 foot sailboat? And what is dangerous?
John

[JohnRPollard]

John,

It depends on a lot of variables. One of the biggest factors is the design of the boat, even more so than length. So while you may have a "28 foot" boat, some boats of that length are built to cross oceans and weather high wind and sea states, while others are intended strictly for light-duty coastal and protected waters.

If your boat is the latter variety, then you will need to experiment to see what kind of conditions it can handle comfortably. I wouldn't suggest experiment in severe weather, but rather work up into moderate conditions and see how it handles them. Also, speak with other owners and get their advice.

In general, 4-5 foot seas should be manageable, but if they are tightly spaced (as is often the case at the beginning of a blow, especially in shallower waters), even seas of this size can be a challenge.

[Bump]

I guess it depends a lot on the boat and the skill of the captain. I have a nice 28' Mariner but I am only sailing for 3-4 years. I tend to stay within my comfort zone of no more than 15-20 knots of wind. Higher seas like more than 4-5' gets a little uncomfortable for me as I am 62 and not as athletic as I used to be and usually sail alone or with non-sailors. Hey, if you want to go hell bent for leather go for it but I like to not have to change underwear every time I go out. MY ideal day 10-15 knots of wind, seas 2-3 feet and all during a weekday so I can play hookie from work. Have fun

[knothead]

Originally Posted by ccriders

I've never sailed in the ocean or gulf, only bays and rivers. So how do I interpret the weather report that says seas 4 to 5 feet, six second period? I understand how to measure wave heights and periods, but what combination is comfortable for a 28 foot sailboat? And what is dangerous?
John

Take little steps.
Note the reported conditions and then go out there and see what they feel like. If you don't like how it feels then duck right back in.

Or reef a little deeper and try it again.

[GeorgeB]

The old rule of thumb (at least for me) is a comfortable sea state is when the wave period (in seconds) is greater than the wave height (in feet). Note that this is for the predominant swell and not for any wind driven waves (which most likely be running at the same time but perhaps from a different direction). Five foot swells @ six seconds are definitely doable in a 28 footer. If you are sitting in the cockpit (assuming that you have a tiller), your eye height is probably between four and five feet above water line so you will probably loose sight of the horizon momentarily when in the wave trough. Another rule of thumb is wave heights taller than your boat’s beam starts increasing the risk of rolling over in a broach. The classic example of this is the (famous) photo sequence of Yachtsea being rolled under the Golden Gate Bridge. However, even “tall” waves can be benign if the wave period is long enough. On waves greater than five feet in a small boat you may start to lose wind in the lower part of the sails while in the troughs and your boat may not have the mass and momentum to carry you over the next crest. Breaking waves will compound your misery. There will be days when it will be more fun swapping lies and stories at the bar than it is sailing out there and breaking all sorts of equipment!

[camaraderie]

Good advice above. Your profile indicates a Pearson 28 which is a sturdy boat but not a Cape Dory etc. so I would first limit myself to 3-4 foot seas and 20 knots of breeze and then just work my way up from there to more challenging conditions. In the gulf...short period waves make a 5 foot wave there quite uncomfortable and harder to take than in the open ocean. You best guide is to avoid the gulf when the coast guard puts out a small craft advisory until you feel very comfortable with your boat and your skills.

[Valiente]

It also depends quite a bit on whether you are running or close-hauled. The latter will usually be more wet and dramatic, while the former will be "rolly" with only the occasional wave overtaking the stern and splashing over the transom.

I agree that you should experiment with a young crew or two and the correct harnesses, teathers and jacklines. Start in 20 knots and three foot seas, and chuck life rings and hats in and see how well and quickly you can "save" the hat. Then try it with a live human if the water is warm and otherwise safe.

I find that a few practice COB drills at the beginning of the season really help me refresh my boat-handling skills in a seaway. This in turn gives me the confidence to tackle bigger waves and more wind, which, after all, makes the boat go.

An alternative tack is to crew on a bigger boat that races in heavy weather, and to gain confidence in that way.

[nolatom]

Lots of good educated and necessarily semi-subjective advice above, since conditions, depths wave shapes, and geograph vary.

But to hazard on a guess on your original question" 5-6 feet with 6 seconds between will be "lumpy", but doable but also kind of exhauting after a few hours.
A 7 or 8-foot wave period would be heaven by comparison, if you could get it.