Balancing the BOAT???????
#11
Registered
Balance
In the end final CG is preference that is representented in a number. A well balanced boat like an airplane is a joy to operate. An improperly balanced boat or plane can kill you.
You want a boat that flies long flat and level.
Steve
You want a boat that flies long flat and level.
Steve
#12
Registered
Join Date: Aug 2005
Location: sint maarten
Posts: 1,491
Likes: 0
Received 0 Likes
on
0 Posts
thats correct. but you trim your aircraft in flight using adjustable control surfaces... just like a boat. the weight and balance are done when its built so that the cg corresponds with the center of lift of the wing. all you have to do is be careful where you put your passengers and luggage. i suspect there are similar centers of pressure both aerodynamic and hydro dynamic on the hull at speed and that it would be really helpful to have that near the cg.
the further apart you get the two, the greater the moment arm and higher the polar moment of inertia will be when you go to turn it at speed. that will translate into a sluggish reaction time and lots of scrub and drag. and , i suppose could make the boat be less user friendly in rougher water as well...
oh well... all well known and understod in the aircraft industry but theoretical as far as these boats go because the hulls are so dissimilar... it would be interesting to know what's actually true in fact.
the further apart you get the two, the greater the moment arm and higher the polar moment of inertia will be when you go to turn it at speed. that will translate into a sluggish reaction time and lots of scrub and drag. and , i suppose could make the boat be less user friendly in rougher water as well...
oh well... all well known and understod in the aircraft industry but theoretical as far as these boats go because the hulls are so dissimilar... it would be interesting to know what's actually true in fact.
#13
Registered
Join Date: May 2008
Location: Tampa
Posts: 108
Likes: 0
Received 0 Likes
on
0 Posts
Simple method from a friend that raced, owned a marina, etc.
He said that the most important factor was the side to side balance, put 2 peices of electrical tape on either side, measuring so if the boat was perfectly level they will match up at the waterline.
Launch the boat and move weight as needed, now you are balanced side to side and will pick up some mph.
#14
Banned
Join Date: Oct 2006
Location: Bradenton Florida
Posts: 5,927
Likes: 0
Received 0 Likes
on
0 Posts
Simple method from a friend that raced, owned a marina, etc.
He said that the most important factor was the side to side balance, put 2 peices of electrical tape on either side, measuring so if the boat was perfectly level they will match up at the waterline.
Launch the boat and move weight as needed, now you are balanced side to side and will pick up some mph.
He said that the most important factor was the side to side balance, put 2 peices of electrical tape on either side, measuring so if the boat was perfectly level they will match up at the waterline.
Launch the boat and move weight as needed, now you are balanced side to side and will pick up some mph.
Take 20 t florjack place it with a 2x4 under the hull ,,where your back is when you sit down or lean against the bolster.
Then move weight until its perfect level on the V with running fuel and place 2 200 pound weights in the seat's.
If you did that your boat is ready to rock.
The side by side movement now also is taken care of because you lifted the boat complettly in the air with the floorjack.
By the way ,,,they also call it trimmtabs. LOL
#15
Registered
Thread Starter
Join Date: Jan 2008
Posts: 70
Likes: 0
Received 0 Likes
on
0 Posts
Thank you!! That is my point!
#16
Registered
Thread Starter
Join Date: Jan 2008
Posts: 70
Likes: 0
Received 0 Likes
on
0 Posts
Simple method from a friend that raced, owned a marina, etc.
He said that the most important factor was the side to side balance, put 2 peices of electrical tape on either side, measuring so if the boat was perfectly level they will match up at the waterline.
Launch the boat and move weight as needed, now you are balanced side to side and will pick up some mph.
He said that the most important factor was the side to side balance, put 2 peices of electrical tape on either side, measuring so if the boat was perfectly level they will match up at the waterline.
Launch the boat and move weight as needed, now you are balanced side to side and will pick up some mph.
#17
Registered
I got some information today. I talked to Rick at Arneson. The Lateral Center of Gravity should be 25% of the length of your hull from the rear of the hull. He said the best way to determine where yours is would be to run a strap under your boat and pick up on it with an overhead crane or something like that.Just pick it up a little bit. If it falls forward. You LCG is forward of that point. If it falls back then it is AFT or that location. Then you can move stuff or ballast accordingly.
I'd like to post pics of my setup but this site charges extra for that, bummer.
Jeff
Last edited by hallj; 01-24-2009 at 02:31 PM.
#18
Platinum Member
Platinum Member
hey..
my bow likes to pop all over with minimal drive input. i've always thought that a few extra lbs in the bow...like 100... would "settle things down" (twin sbc's in a 26'er), thus really letting the drives and tabs do their job. a more level ride w/o dragging tabs must surely improve efficiency?
c
my bow likes to pop all over with minimal drive input. i've always thought that a few extra lbs in the bow...like 100... would "settle things down" (twin sbc's in a 26'er), thus really letting the drives and tabs do their job. a more level ride w/o dragging tabs must surely improve efficiency?
c
#19
Gold Member
Gold Member
Join Date: May 2002
Location: DFW
Posts: 1,127
Likes: 0
Received 0 Likes
on
0 Posts
The 26% represents a working number to create a CG envelope. As loading and/or load locations change, the CG will move within the envelope. Therefore,variables such as a high X,heavy load,hot dry days etc. may cause the boat to have trouble getting on plane.
Therefore,is it prudent to include a forward located ballast tank in this discussion?
Therefore,is it prudent to include a forward located ballast tank in this discussion?
#20
Platinum Member
Platinum Member
Cat,
We have a ballast tank in our boat but don't use it often. The thought was a ballast tank in the bow would allow us to run faster overall in the bumps while using less tab. I expect there is a balance of both ballast and tabs but we never figured it out. How do you measure the results? It seems we could exceed the speed we were comfortable with using either system.
I would like to hear move from others that use a ballast tank. Is a ballast tank mostly a band aid for a poorly balanced boat?
Steve, do you race with a ballast tank?
We have a ballast tank in our boat but don't use it often. The thought was a ballast tank in the bow would allow us to run faster overall in the bumps while using less tab. I expect there is a balance of both ballast and tabs but we never figured it out. How do you measure the results? It seems we could exceed the speed we were comfortable with using either system.
I would like to hear move from others that use a ballast tank. Is a ballast tank mostly a band aid for a poorly balanced boat?
Steve, do you race with a ballast tank?