Where Should My Center Of Gravity Be?
 

I originally set my Revolt 30 up with a rather heavy Garmin GPS in front of the batteries so I could see which prop would give me the most mph. Now that Ihave chosen a prop which works quite well I took the Garmin out. Went to run the boat today and noticed a little problem. It runs smooth and true at half throttle but when running WOT the bow gets a little too light and the whole boat rocks violently from side to side. If I don't back off on the throttle it will get airborn. Before I adjust the plane tabs in the back I thought Iwould find out if my CG was even close to where it should be. On a 30" hull without the Garmin weighing the front down my CG was about 8" from the stern. I decided to shift the batteries forward in the tray and now the CG is 9 1/2" from the stern. I will test it out tomorrow but just wanted to ask if there was a general rule where the CG should be?

Thanks in advance for your help,
MadDog

RE: Where Should My Center Of Gravity Be?
 

A good rule of thumb is 28%-33%, 28 being 8.4" from transom, 33 being 9.9" from transom for a 30" hull.

RE: Where Should My Center Of Gravity Be?
 

Thanks, that is what I needed to know. It looks like I was 27% but now set up better at 31.5%.

MadDog

RE: Where Should My Center Of Gravity Be?
 

also the prop can toss the hull around like your describing
a prop with more lift will cause the boat to run loose

RE: Where Should My Center Of Gravity Be?
 

srt10:

I thought about the prop but the boat was very stable with the weight of the Garmin in front of the Lipos. The problem started when Iremoved the Garmin. I have shifted the Lipos forward changing the CG and will test it out tomorrow. Iwill report back after tomorrows run.

MadDog

RE: Where Should My Center Of Gravity Be?
 

keep us posted bro

RE: Where Should My Center Of Gravity Be?
 

Well, it looks like I got the CG correct. Runs like a dream WOT. Very stable and fast, nose comes up so the last 1/3 of the boat is in the water but will not get airbornand will turn on a dime on command. My only goof up today was that I ran it WOT until the batteries were depleted which caused the batt / ESCwires to get so hot they melted some of the floatation noodles I had stuffed down the sides. Next time if I run WOT it will be for 6 minutes max.

MadDog

RE: Where Should My Center Of Gravity Be?
 

Awesome news!!
What prop did you go with Dan?

RE: Where Should My Center Of Gravity Be?
 

I got a prop from Chris that he sharpened and balanced for his Revolt 30. It isa 47x50 and Ibelieve the stock prop is a 42x55. Not positive about those sizes but my GPS shows a definite increase in speed.

Dan