Experience with bimini in higher winds

[Calin]

Experience with permanent/deployed bimini in higher winds

Last day I was sailing on winds of 25 mph with my bimini top installed, reefed main and genoa. I have noticed a dramatic increase in heeling and uncontrollable rounding into the wind. Thinking about it made sense. An area of 30 sq ft, as the boat is heeling it catches more wind, and, been aft would push the boat into the wind. However, I was not expecting it to be this significant.

What is your experience in this matter? I know, few will say, collapse the bimini. However, in my configuration I want to install a solar panel (~6x3) and a bimini top to cover the cockpit. So collapsing the bimini would be possible but the solar panel will still offer 18sq ft to the wind.

[RobertB]

Do not have much to say about bimini affecting sailing performance but I can attest to the fact that high winds not likely to damage it (at least the 90 mph derecio winds earlier this year).

[kevinnem]

I have to disagree with that. In high winds, and (likely in large part due to ) sun exposure I have had a bunch of the thread come apart on my bimini, I have lost about ... 1/2 of it I think, afew more weeks of exposure and I think it would have come apart totally.

I am resowing it this year, might try to update the color, and stuff, make a new one, I don't know.

Kevin Nemrava.

[Crikey]

I suppose some aspect of the particular design could grab more wind than others, but mine is high, and flat, and seems to act somewhat as a steadying sail, which helps to reduce fore/aft pitching. Rounding up at higher wind speeds more often implies you're carrying too much sail.

[NiceAft]

You say the Genoa was also reefed. How much? Could you have safely let out more? If your speculation is correct about the bimini, the boat then needed to be better balanced by letting out some of the genny. Also, how far were you heeling?

Ray

[Berber Boy]

I had a nasty experience with my bimini after I had dropped sail due to approaching weather and was motoring home at about 5knots. My bimini was up and adjusted back to cover the helmsman seat. Huge gusts in excess of 20knots came across my port forequarter and hit the bimini almost like a spinnaker in reverse. It did not tear but it turned the boat stern considerably even with my etec putting out 3000rpm. I dopped it real quick and all was well but under some conditions upwind and in a more laid back position it does affect sailing performance on my boat.

BB

[Calin]

I had a nasty experience with my bimini after I had dropped sail due to approaching weather and was motoring home at about 5knots. My bimini was up and adjusted back to cover the helmsman seat. Huge gusts in excess of 20knots came across my port forequarter and hit the bimini almost like a spinnaker in reverse. It did not tear but it turned the boat stern considerably even with my etec putting out 3000rpm. I dopped it real quick and all was well but under some conditions upwind and in a more laid back position it does affect sailing performance on my boat.

BB

That is what I was afraid of. Having an horizontal surface with heeling its profile to the wind increases. The Genoa could be used for balancing but with heeling its surface decreases. If the bimini is far aft its impact in turning the boat into the wind would be amplified. If it is high, its impact in heeling would be amplified as well.

As you did, I now considering having a removable bimini. However, if I am making an analogy to your and my bimini experience, I am worried of what would be the impact of having a solar panel that would be constantly on. Would the fact that the solar panel is flat (as opposed to the parachute like bimini shape) help? Acting like a wing and offering less wind resistance?

[Calin]

You say the Genoa was also reefed. How much? Could you have safely let out more? If your speculation is correct about the bimini, the boat then needed to be better balanced by letting out some of the genny. Also, how far were you heeling?

Ray

Ray,
I think my genoa is a 150 and was about 1/2 reefed. I only have one reefing point on my main.
Wehn I lost control it ws around 45%. I could feel the jerk on the bimini poles and the bimini itself acting like a chute. My eyes were more on it thinking it will take off.

[NiceAft]

It's reading more and more like the bimini is the culprit.

The factory sail only has one reef point, and it is more like the second point on sails which have two, so you were fairly well reefed.
Ray

[DaveB]

Never had that problem even in 40 knot winds. Bimini will always effect sailing performance in high winds. fold it up and latch it down.
Beter yet, reef the Bimini.
Dave

Experience with permanent/deployed bimini in higher winds

Last day I was sailing on winds of 25 mph with my bimini top installed, reefed main and genoa. I have noticed a dramatic increase in heeling and uncontrollable rounding into the wind. Thinking about it made sense. An area of 30 sq ft, as the boat is heeling it catches more wind, and, been aft would push the boat into the wind. However, I was not expecting it to be this significant.

What is your experience in this matter? I know, few will say, collapse the bimini. However, in my configuration I want to install a solar panel (~6x3) and a bimini top to cover the cockpit. So collapsing the bimini would be possible but the solar panel will still offer 18sq ft to the wind.

[Calin]

Thank you Dave. That is what I was thinking regarding the bimini. The problem is that I wanted to install a solar pannel. That would be difficult to reef

Never had that problem even in 40 knot winds. Bimini will always effect sailing performance in high winds. fold it up and latch it down.
Beter yet, reef the Bimini.
Dave

Experience with permanent/deployed bimini in higher winds

Last day I was sailing on winds of 25 mph with my bimini top installed, reefed main and genoa. I have noticed a dramatic increase in heeling and uncontrollable rounding into the wind. Thinking about it made sense. An area of 30 sq ft, as the boat is heeling it catches more wind, and, been aft would push the boat into the wind. However, I was not expecting it to be this significant.

What is your experience in this matter? I know, few will say, collapse the bimini. However, in my configuration I want to install a solar panel (~6x3) and a bimini top to cover the cockpit. So collapsing the bimini would be possible but the solar panel will still offer 18sq ft to the wind.

[mastreb]

Acting like a wing and offering less wind resistance?

Short answer yes, so no: it will act like a wing and do what wings do, which create a similar amount of vertical lift as your Bimini per sq.ft. The Bimini is a better parachute, but any surface presented directly to the wind will increase windage and in fact a hard surface will create lift earlier and help the boat to heel faster. Not to mention the increase in aloft weight adding to heel as well. This wouldn't be to the level of creating a safety issue, but it will certainly contribute to rounding up and "weather stern".

If you are routinely dealing with 20 knot plus gusts and you don't like the rounding up, consider putting you panels elsewhere. If this is an occasional situation, I wouldn't worry about it.

Matt

[Phil M]

I was beating into the wind with a reefed main, and experimented with the Bimini open and flat compared to being bunched up and tied together at the stern. I gained speed of less than half a knot with the bimini open and flat. I repeated the experiment, and measured the same results. I suggest that the wind resistance of a furled and tied up Bimini made the small difference.

[Calin]

I was beating into the wind with a reefed main, and experimented with the Bimini open and flat compared to being bunched up and tied together at the stern. I gained speed of less than half a knot with the bimini open and flat. I repeated the experiment, and measured the same results. I suggest that the wind resistance of a furled and tied up Bimini made the small difference.

this sounds like good news. I assume the winds were strong for you to reef the main, so it is good news. How big is your bimini? Have you noticed significant increased heeling ?

I have posted a mod that pictures the structure I want to use for the removable bimini and permanent solar pannel. I consider a solar pannel ~6x3

http://www.macgregorsailors.com/modt/in ... ewimg=3528
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[Phil M]

My Bimini would be considered normal size for a 26M, enough to cause slight speed changes when used differently. I would have to measure heeling to notice any changes.