full keel design ?

On a full keel sailing hull, how much consideration should I give the keel in
figuring the lcb and Cp.

Frank

 

For Lcb of course.. For Cp a more controversy.. Normally keels are not included but full keels are a bit different animals. I counted it separately as an independent member bcs it's a bit shorter than the hull but kind of "full" anyways.. Wanna hear some NA insight to this too..

 

Sure , I am a good listener .
thanks

 

Me too so let's wait together for someone

 

LCB is a "real" and useful centroid, I can't see how leaving the keel off would produce anything useful. The volume of the keel will make a difference in how she floats....In a fin keel boat the volume and center of the keel is added to or calculated in with that of the hull. Full keels often have little or no defining separation point from the canoe body, so I would include the keel as a matter of course.

On the other hand Cp is a "comparison" factor....you will use it in comparing your hull with others and with an ideal. So you look at it's derivation in light of the comparison. At BKYD we used to calculate Cp with and without the keel if there was an obvious separation point, otherwise it's all together. Cp is mostly useful for comparing canoe bodies though the number with keel can be useful as well.

 

Tad , I that helps a lot , I thought that might be the case. I have found differing ideas about it , but it make sense to collect the data separately in the beginning.
thanks , Frank