seamanship question

[powderhombre]

I'm sure most of us have watched the TV show Deadliest catch. How a 130 + foot ship is rolling and plunging in 30 foot seas. I find it amazingly scary and the captains handle the situation it seems with little concern. ( I'd be scared to death). so my question is.. if a 130 boat can handle 30 foot seas, is there a ratio that applies to all boats in general? so 130 divided by 30 equalls 4.33. or roughly 1 fourth. so.. can the maximun wave for a 20 foot boat be 5 feet? would the effects be the same? I do reallize hull type wieght and skipper abilities are all factors, just a general rule of thumb question.

 

[highN'dry]

Re: seamanship question

No, not really, the deep draft trawler with a weighted keel and self righting capability is nothing like a little fiberglass lake boat. Most small boats are rated A, B, C, D categories from small lakes to open ocean crossings. Most of the boats you see about are A category for small lakes and protected bodies of water with a max wave height less than three feet. Our 19 foot BW Outrage is rated cat B for large bays, near shore and coastal cruising with wave heights to six feet. I have been in worse, try to avoid that if possible. If I were to move up to the Outrage 22 I would jump to cat C for offshore use. Cat D indicates a boat capable of surviving the open ocean, crossing an ocean, and taking on any weather that might be dished out.

The catagory thing is really quite flawed, I have been out in 12 foot swells but they had a large frequency and it was very comfortable and safe, I have been out in sharp three foot confused chop that beat my brains out and made me wish I was on shore.

 

[rp23g7]

Re: seamanship question

After watching the show and seeing the Wizard and Northwestern and North American close up, I cant imagine what a 30 or 40 ft sea is really like in those boats.

Watching them in the show, you see the bow plunge almost to the water, then seeing how far the bow is actually from the water when its sitting there, wow thats a big wave.

Take away the wind and flying spray etc, and just put the waves in the equation a 40 ft sea in a 20 or so ft boat would be kinda fun, just like a roller coaster...... i am being silly of course.

 

[MushCreek]

Re: seamanship question

Oddly enough, a short steep chop is probably a lot more dangerous to the small boat than bigger waves (unless they are breaking). I was once out on a large commercial dive boat in 10-12 seas, and we were making pretty heavy weather of it. Waves would break over the stern, with the water coming up to our knees before draining out of the scuppers. A couple hundred yards away, there were two guys diving out of a 13' Boston Whaler. They were completely dry (other than the diving part), with the little boat riding up and down smoothly like a seagull. I reminded my wife of that day when I bought my 13' Whaler.