Skilled helmsman

[HAL]

Autopilot ,broad reach, broach.
In Youtube Vendee globe onboard videos, Roxy and Ecover for example, are on a broad reach in 35k, going 15k and surfing at 25k in heavy seas. I would think it would take a skilled helmsman to anticipate wind and wave to avoid a broach. How can an autopilot do this?

 

[sailingdog]

Autopilots don't avoid broaches.

 

[Bill Roosa]

the prudent sailor

i would recommend that you not use an auto-pilot in a situation like that. Course going 15+ knots will give you some advantage as you may be sailing at or even exceeding the local wave speeds. kinda like steering around the speed bumps in the parking lot.
A prudent sailor/team would be using the auto-pilot prior to and after the worst of the storm and have an actual helmsman at the wheel during the worst of it. Develop a rest plan so you don't get into a situation where the worst of the storm hits after your crew has been up for 24 hours.

 

[caguy]

The autopilot has nerves of steel (copper anyway). When soloing it the AP helps me hang in there where I might otherwise bail. It also allows me to manage the sheets and maintain boat balance.
Frank

 

[Todd Smith]

Skilled autopilot

Those autopilots used by the Vendee racers get input from the wind instruments for speed and direction as well as boat speed, compass heading and yaw rate. They also are programed to understand (somewhat) the response of the boat to all these inputs.

But they still broach sometimes

They have to be careful not to have too much sail up, or they would broach.

To Bill Roosa: These people are racing the Vendee Globe ! Prudence has nothing to do with it !

 

[Bill Roosa]

Prudence or not

I understand the learning of the auto-pilot using networked wind, speed, flux-gate.......
I've done this on my boat and you do get a pretty good effect when/once you get it all dialed in. Those first few minutes can get kinda hairy as Outo gets the hang of the sea state but once he gets done figuring things out you only have to worry about "rogue" stuff and simply being over canvased.
Prudence would dictate that they finish the race to win. That is what it is all about, right? Not much glory for those who get towed in upside down sans a mast now is there?

 

[Todd Smith]

...snip...
Prudence would dictate that they finish the race to win. That is what it is all about, right? Not much glory for those who get towed in upside down sans a mast now is there?

Yeah, but being too cautious would make them slow and lose. It seems to be the critical question for these skippers, push as hard as possible, but not too hard.

One of the leaders was just dis-masted. He didn't capsize, the mast just fell down. The designers have to push for lightness, sometimes they push too hard as well.

 

[Franklin]

Also would like to add that the back end of a storm is very danerous as that's the time for the confused seas which leads to occasional very big wave. I've read many stories of racers out in bad stuff and they lie to a drogue after they've reach exhausion (not the boats with 15 crew members) and they tell of getting popped on just when they thought the storm was pretty much over.

Same thing happened to that cruise ship that got hit by the rogue wave in 2005. They went into port due to a storm. When the winds died down a little, they left the port thinking it's dying down and the storm is over but got hit with a 100' wave.

So don't let your guard down just because the winds are dying down.

 

[Stu Jackson]

If you read the instructions that come with autopilots

they ALL say that sail trim and correct balance (i.e., reef when it's windy) is necessary to have the autopilot work properly, if at all. This is regardless of how interconnected the AP is. I haven't looked at the racing photos, don't know if they have separate wind vanes, but most recreational sailors doing ocean work use wind vanes, not APs, for bad weather which the AP usually (remember, we're talking recreational boats) doesn't work too well.

Our experience with our modest Autohelm ST3000 is that we learned very quickly how to balance the sailplan to reduce the need for oversteering with the AP very soon! We became better sail trimmers with using the AP. Not a bad deal, huh?