Estimating LCG

[Clinton B Chase]

I am in the process of persuing old threads but still wanted to ask a question for guidance. I am drawing an 18 1/2' sail and oar dinghy, 6'ish beam and 10" draft max, cat-ketch rig. I know that I could just skip the LCG step at this point and have enough background to know that it will likely be aft of amidships in my dinghy shaped hull, but I wondered if there were some rules of thumb for how far aft it might be...just to have that understanding. I realize that the people, gear, etc inside will be the primary thing. But is there a % range along LWL type figure for location of LCG in a sailing dinghy shaped hull.

I usually use Cp of 0.56 for sailing dinghy hulls...seeing as this is more towards sail & oar land should I still use the same Cp?

Cheers,
Clint

[Gilbert]

Using a Cp of 0.56 is fine. If the wind comes up you will no doubt sail. If it is calm the Cp will matter little. However if you want to enter rowing races you might want to lower it some, but 18.5' is a little on the big side for one rower.

[Clinton B Chase]

TX...I hope I only have to row to get back to the boat ramp or out of a lee...otherwise sail is what I'll have up and in light air I hope to be able to ghost along so I plan to keep the transom out of the water for rowing and light air and under sail in a breeze the transom will be in the water. How slack I'll keep the sections? I'll let my brain and hand decide when I get to drawing the midship section next.

Still curious where I might predict the LCG to be as a 'rule of thumb'.

Cheers,
Clint