Small Powerboats into High Wind

[Ratty1978]

Experienced an interesting situation and continued safely based on judgment and decisions, but it makes me wonder if there is some engineering or naval architecture quantification. 22 foot center cockpit outboard, forecast for wind from shore, so no fetch for near shore waves, front passed earlier than expected on a return trip. Wind shifted from about 270 to 360 and course was also about 360. Wind was about 30, so an unusual situation of whitecaps, but only 1 foot waves. There was also a peninsula about 4 nm North. Slowed to keep boat substantially level, and returned safely. But in those powerboats, if you increase power, the bow rises and stern squats, before you plane. Any planing into 30 was not even considered. At what speed (boatspeed + windspeed is still apparent even in a powerboat) and bow "plowing" angle is stability lost? As an aside, for a Piper Cherokee 140 Vr (velocity at which you rotate the airplane's nose off ground to take off) is 60 mph, so 10 knots + 30 knots = 40 apparent in a boat is of "statistical concern".

[ranger58sb]

Can't predict an exact speed.

Too much depends on boat weight (and weight distribution), hull shape and length, sea states (wave height, period, and direction relative to travel), wind action against hull (and/or T-tops or whatever)... and whether you might be able to "surf" the boat or not. Probably 5-10 other factors.

"Slowed to keep boat substantially level, and returned safely." is pretty much a seat-of-the-pants technique.

-Chris

[CaptTom]

You did the one correct thing many planing hull operators just don't comprehend: slowed down.

the exact speed would be a function of hull speed and conditions. Personally, if I understand the conditions in this case, I'd push it to a bit above hull speed. This gets the bow up a little and maintains good steerage, without getting up on plane and trying to "fly" over the wave crests. Depending on the hull, bow-up might keep you a bit dryer, too. Just don't let it come up so high you lose visibility. That point is going to be different for each boat. If the seas were a bit confused or coming anywhere abaft of the beam, I'd retract any trim tabs, too.

[mvweebles]

Many variables. A few days ago, I was on a Parker 21 CC with a fresh Yamaha 250. Relatively deep vee hull made for ocean chop. With the 250hp, she pops-up on plane within a couple boat lengths even with the deep vee. It's an E-TIcket ride at 30-kts, and you have to keep an eye for the occasional set of bigger waves, but she does okay at pace in chop.

A day after, I was on another friend's Century 20-foot CC with a fresh Yamaha 150 SHO. More of a crossover/inland boat. Much flatter stern sections so it planed-off pretty quickly even with the smaller engine. But pounded noticeably more even in slightly less chop.

A lot of variables. But I'd say more horsepower and deeper vee hull would definitely make life easier (and more fun) in open water chop. More expensive to run though - deep vee takes more hp to plane.