How to Balance/Find the CG of a Boat by Percentage

You may have heard people talk about balancing their hull by percentage. This is very important to establish the best performance for a perticular boat hull design. There are some general rules of thumb that may apply as follows:

V-bottom boats generally balance between 27-30% pecent forward of the transom.
Catamarans generally balance between 35-40% forward of the transom.

I strongly reccommend that you inform the manufacturer of your hull what type of power and hardware you'll be using and allow them to instruct you on the best balance point for their model.

Heres an example to establish balance/cg by percentage.

1/ Measure hull length from bow to stern with a strait edge ruler.
2/ Convert desidered perfectage by adding a decimal point before the digits.
3/ Multiply the total length times the converted percentage. This will equal the balance point in inches forward of the transom.

Example on conventional V-bottom boat:
50 inch boat with a 30 percent balance/cg point would work like this
50 x .30 = 15 inches

Your CG would then be 15 inches forward of the transom. Given that the engine is the heaviest component, start by placing the engine in the boat slightly behind the balance point/cg, then tenatively place a full gas tank (filled with water for a safe test) followed by the radio box behind the engine, transom hardware, and exhaust system, etc. The radio box, gas tank, and engine can all be manipulated slightly forward or backwards until the boat balances on the 15 inch mark forward of the transom. This is the basic foundation for establishing CG.

Good luck model boaters,
Tony Castronovo