Rolling Over

[George Lamb]

I often have take guest sailing, and as the boat begins to heal they invariably ask if it is possible to tip over. My standard answer is that the keel is heavily weighted, and the bigger the boat, the harder it is to tip. I am interested in getting more information. Has anyone here ever rolled one. Under what conditions?

 

[Jim Ferretti]

Rolling Over (Felt like it)

A couple of years ago we were motoring back in the aftermath of a storm with 4-6 waves (Lake Erie type - short peak to peak distance). A couple of rather large waves hit us broadside, the first one rolled us about 35 deg and the second about 45 deg. The second one rolled my better half out of the bunk (she was a little green around the gills). While it felt as if we were going over the boat came back up with no trouble at all. Hunter makes a good safe boat! Happy sailing.

 

[Gordon Myers]

Roll Over Possible But ....

Wave-tank testing by Southampton U. indicates that beam-on BREAKING waves with a height of 55% of hull length will over-whelm all monohull form/ballast combinations. Further all designs could be rolled past 130 degrees by BREAKING waves with wave height s of 35% of LOA.

 

[Bob E.]

Southampton U. results

Gordon, your information is fascinating. Can you elaborate further?I'd really like to know more.

 

[Don H.]

Roll over possible with large seas.

In theory, any design that Hunter builds can roll over given big enough waves, with breaking crests and surfing conditions, maybe like the Fastnet race tragedy 20 years ago. In practice, I've never heard of any Hunter rolling over. I personally had one experience with my Legend 37.5 where a gust of wind caught me coming out of a tack, just as I had sheeted the sails close hauled and just beginning to accelerate. The gust laid my boat over so far that the handrails on the top of the cabin were underwater. That got my attention. By the time I broached, the gust had passed and everything was back to 10 to 12 knots of wind. I guess it was clear air turbulence.

 

[Rich]

South U. results

That's the closest information I've seen to a quantifiable measure of what will actually roll a boat. I'd love to know more. How does the capsize screen figure into that calculation? Could breaking waves alone do it or is there a wind factor that goes with it?

 

[Gordon Myers]

MORE On Southampton U. Study.

As I understand it, the wind alone would probably never ROLL an off shore sailboat. Knock down - yes, roll - no. It takes Breaing waves to roll the boat, but you won't encounter Breaking waves, (off shore)with out very strong winds. There is a great report in "Blue Water Sailing" (July/August 1999), "A Fresh Look At Storm Procedures" discussing the Southampton study, but going much further. There are several other good reports in that issue, which was a Special Report on "Heavy Weather Saling" including "Trimming Storm Sails".