Yacht Stability

Thread starter #1
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!


Upside down?
Staff member
What kind of stability do you want to focus on?
The Laser is an entirely different beast among the three mentioned above.
It can by docile in light winds but at other times it can be quite squirrely (downwind in a blow). As mentioned, you need to specify the conditions for your stability study if you want meaningful contributions.
Thread starter #3
I am looking at peoples attitudes towards the stability of there vessel and whether it is an understudied topic, hence the focus on the three different types.
For example the laser CE certificate states a maximum load of 175kg or 3 people but if someone where to exceed this what would the consequences be? Is this weight allowance made aware to new owners? Does the owners handbook have any information on the conditions it is suitable to take the boat out in?


Upside down?
Staff member
OK; with respect to the Laser, just about anybody who buys one is aware that capsizing is a fact of life, especially as one learns to sail the boat/beast. I wouldn't say that this is an understudied topic.
Lasers are typically sailed solo, hardly ever with two and only as a fun thing to do for youngsters with three (when the water is warm).
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Seems you are approaching two separate issues here. Stability of vessels is a very thoroughly studied subject, and - to oversimplify - is a product of hull shape and load distribution. Marine architects know how to design a boat for stability, at the expense of forward efficiency - and vice-versa. A given boat design may be weighted more one way or the other for specific reasons related to the expected use. A racing design may give up some stability for speed, yet an experienced boater will not feel unstable in it.

That brings us to the other issue - the boater's "attitude" towards stability. A knowledgeable boater will base his boat choice on what is important to him. If he is a racer, he will likely not value lots of initial stability (you need to study up on the difference between initial stability and secondary stability). If he is looking for a fishing platform or possibly a live-on craft that spends more time at dock than at sea, initial stability may be more important than speed or secondary stability. Sadly - many people get into boating without knowing the difference or having anyone explain it to them. So, there are three "attitudes" for you. "Need it"..."don't need it"...and "don't have a clue".