Laser Stability

Shiggs

New Member
Hi, I am a 3rd year student at Plymouth University studying Navigation and Maritime Science.

I am starting research into my honours project in which I am looking at yacht owners attitudes towards stability. I am focusing on three particular vessels, a Laser dinghy, Dufour 445 and a Nordhavn 55. I will be conducting an inclining experiment on the Dufour 445.

I would really appreciate if anyone has any information about the stability of these vessels or owns one and knows what information was given to them when they bought the boat.

Your help would be much appreciated!
 
Not sure anyone could tell you much from a technical point of view, other than the boat does not have positive roll stability. I don't think any small sailing dinghy does. To most Laser sailors "stability" means learning to control body position and sail trim, particulary in a big breeze. The only way to learn it is to go out and flip the boat a few times. Or many times as the case may be.
 
You should be able to calculate the moment of stability and/or the dynamic stability/static stability of each of these vessels using the carene diagram. I assume you know what this is as you're studying maritieme science. If not I can try to explain, let me know.

The laser has very little stability, the centre of mass is almost entirely dependent on the location of the centre of mass of the sailor.
The Dufour 445 has a very high stability, it should be self righting, even if it's turned 180 degrees.
The Nordhavn 55 should behave similarly.
Try finding the rightning arm curves for these or similar boats

The experience of stability will be very different. In a laser an inclination of 45 or even 90 degrees is nothing to worry about.
For the Dufour 30 degrees wil probably cause a little discomfort/panic. Mostly because while the sailors might know their boat is selfrighting, it's not really something you want to try.

For massive cruiseships the "angle of panic" is about 5!! degrees. For the Nordhavn this angle will be sightly bigger, but as this is a rather large yacht and it's not supposed to tilt over, the angle of panic will be much smaller than on a dufour or laser.
 

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