How "easy" -- or difficult -- is it for boats with flybridge to tip over?

bluestar · 04-01-2012, 11:47 PM

I just bought my Carver 36 Aft Cabin! Now this question: That flybridge seems mighty high... How easy is it for it to tip over? I have seen videos of Carver 32 going at 15 knots and pulling a 100-yard U-turn and it seems to do fine. So where is the limit on this boat?

Capt J · 04-02-2012, 12:17 AM

It all depends on the speed of the vessel. If the vessel is at rest, it's most vulnerable, the type of wave, and so many different factors. I'd say if you're in the middle of the ocean, drifting, beam to, 10-12' would probably be that point.

RB480 · 04-02-2012, 07:26 AM

A lot harder to do than you would think.

Marmot · 04-02-2012, 07:52 AM

Quote:

Originally Posted by bluestar

That flybridge seems mighty high... How easy is it for it to tip over?

High? It is just canvas and clear plastic. Any wind strong enough to blow the boat over will rip it off and reduce the windage pretty quick.

If the boat rolls far enough to worry about you will most likely be tossed off the monkey island and the GM would increase. While you are swimming back to the boat you will see that it did not capsize.

PropBet · 04-02-2012, 10:55 AM

Sounds like a little tuna fishing is in order. (with a beam sea, while fishing in the trough)

Will give you a whole new perspective on a boat righting itself.

Capt J · 04-02-2012, 11:22 AM

Quote:

Originally Posted by PropBet

Sounds like a little tuna fishing is in order. (with a beam sea, while fishing in the trough)

Will give you a whole new perspective on a boat righting itself.

Come on now, that tower is nothing compared to the one on "cookie too". This one will really make that pendullum swing.

bluestar · 04-02-2012, 01:21 PM

My boat has 7 seats on the flybridge. I'm just thinking with that many people on top of the flybridge, can it tip over more easily. The other factor I'm wondering about is the centrifugal force. Is a Carver designed so it won't tip over at tight turns?

In this sales ad video below, when the boat turns at higher speed, the boat leans toward the inside a bit. Does this happen naturally or is there some special maneuver?

Carver 30 Santego For Sale By South Mountain Yachts, (949) 842-2344 - YouTube

Capt J · 04-02-2012, 02:00 PM

A 46' Bertram with a tuna tower rolled over inside of Hillsboro Inlet many years back while it was sitting in relatively calm water (no more than 1 or 2 foot rollers). The cause was determined to be the 7 or so people standing in the top of the tuna tower which upsetted the stability too much.

Seafarer · 04-02-2012, 04:18 PM

Quote:

Originally Posted by bluestar

The other factor I'm wondering about is the centrifugal force.

Without intending to be pedantic, why worry about something fictional?

Marmot · 04-02-2012, 04:28 PM

If you really really want to know if the worry is ficitonal or not but don't want to spring for a real inclining experiment, try this:

http://www.uscg.mil/forms/cg/CG_4006.pdf

Bayside Bert28 · 04-02-2012, 06:58 PM

Something to keep in mind is that the Carver is not known as a big water boat. So, while its not going to tip over if you have the seats filled on the fly bridge while riding in normal conditions, you will feel the effect on the handling and probably be a happier Captain with the weight distributed. And if the weather begins to pick up, my guess is that the guests will quickly look for a seat below.

I have a Bertram 28 that we will sometimes load over 10 on. I distribute the weight within reason and the guests are happy to ablige.

NYCAP123 · 04-02-2012, 08:31 PM

There are boats and there are boats. Everyone except Bert seems to have missed that this is a 36 Carver AC, and not a Bertram SF. I've had Carvers to the edge in Quartering seas. Wouldn't want to see this in more than 7', and sure wouldn't make any guarantees past that point.

dennismc · 04-02-2012, 08:40 PM

I was once informed by a very knowledgeable delivery Captain that he used the following guidelines when doing long coastal deliveries.

A typical cruising style motoryacht may be considered at risk if in a fully developed beam sea, the combined wind wave and swell height of the sea is equal to or greater than 20 % of the water line length of the vessel.

So, a boat with 60 ft w/l could be in serious danger for turning over if laying in a beam sea of 12 ft.

So I was told....seems a reasonable guideline and good place to stay away from....

NYCAP123 · 04-02-2012, 09:05 PM

You're not far off on your conclusion, however there are a lot more factors to be considered. A deep draft, keeled, heavy or low vessel would be far more stable than a light, tall, shallow draft one. Wider beam, hull shape, cat or mono, balast, etc. are also factors. More math than my feeble mind can compute. I just know it when I feel how the boat reacts or by the stability cert.

Seafarer · 04-02-2012, 09:08 PM

Quote:

Originally Posted by Marmot

If you really really want to know if the worry is ficitonal or not but don't want to spring for a real inclining experiment, try this:

http://www.uscg.mil/forms/cg/CG_4006.pdf

"Centrifugal force" is fictional no matter how many pieces of paper you have to claim yourself an "expert" about boats, guy. Knowing one's way around the bilge doesn't give one license to defy laws of physics.