Hull speed calculation

Not sure if this is a question I am going to regret asking.

My boat (Keel/sail) is 26 foot (overall), is there an (easy) way for me to calculate what the maximum hull speed would be?

It does not have to be precise to the final .5 of a knot just a ball park figure.

Mychael

 

Hi Mychael, Depending on whether your boat is light or heavy for it's waterline length, hull shape, and sail size in relation to overall displacement as the main factors. Keeping the above in mind refer to Froude's Law:
http://www.boats.com/boat-articles/Design and Construction-109/Understanding the Numbers/1255.html
This Law will give you a maximum for a keel sailcraft assuming that it does not surf down a wave or commence planing. Sounds like around 6.5 knots should be definitely achievable, perhaps a little more.

 

Thanks for the link.. Looking at it all I'm sorry I asked. hahhah.

The 6.5 knots you've quoted is close enough for me.

Mychael

 

http://www.sailingusa.info/cal__hull_speed.htm

 

Remember, Froude "hull speed" has nothing to do with the maximum speed atainable by a vessel, it will only give you the approximate speed of the first "hump" in the resistance curve. If you have enough power, you will climb over that hump. Depending on several factors, such as length/displacement ratio, sail area/displacement ratio, and stability ratio; speed under sail may be significantly higher.