Center of gravity?
09-20-2022, 09:38 AM
#61
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iTrader: (1)
”On modern Deep V hulls, this is done for better balance, front to rear, but mainly to get the two engines closer together than you could if they were literally side by side. This closer placement allows the outdrives to be closer together as well, and closer means they can mount the drives deeper in the V of the transom. This helps get more of the hull out of the water when on plane.”
and this thread:
https://seriousoffshore.com/forums/s...ad.php?t=15663
All above prob not absolutes, but good info/ideas/etc
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hogie roll (09-20-2022)
09-20-2022, 09:42 AM
#62
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Thread Starter
Thanks again.
Much appreciated.
And a 104 mph Panther???
Holy hell Batman!
So they did their kilo run and race conditions with that same C of G?
Much appreciated.
And a 104 mph Panther???
Holy hell Batman!
So they did their kilo run and race conditions with that same C of G?
Record Breaking Scarab Panther
What is the fastest panther
you'll have to dig but there is a thread on the set up and why
What is the fastest panther
you'll have to dig but there is a thread on the set up and why
09-20-2022, 09:50 AM
#63
Registered
Thread Starter
35% of 25’ hull is 8’9”.
Sooooooooooooo………., if a build a small cradle to fit the keel of my boat, in that general area, buy a stronger floor jack and just start lifting it until it starts lifting evenly, as in not bow first etc, I think I’d find what I’m after.
Sooooooooooooo………., if a build a small cradle to fit the keel of my boat, in that general area, buy a stronger floor jack and just start lifting it until it starts lifting evenly, as in not bow first etc, I think I’d find what I’m after.
09-20-2022, 10:12 AM
#64
Registered
Thread Starter
More great reading!
Thx!
Thx!
Found this:
”On modern Deep V hulls, this is done for better balance, front to rear, but mainly to get the two engines closer together than you could if they were literally side by side. This closer placement allows the outdrives to be closer together as well, and closer means they can mount the drives deeper in the V of the transom. This helps get more of the hull out of the water when on plane.”
and this thread:
https://seriousoffshore.com/forums/s...ad.php?t=15663
All above prob not absolutes, but good info/ideas/etc
”On modern Deep V hulls, this is done for better balance, front to rear, but mainly to get the two engines closer together than you could if they were literally side by side. This closer placement allows the outdrives to be closer together as well, and closer means they can mount the drives deeper in the V of the transom. This helps get more of the hull out of the water when on plane.”
and this thread:
https://seriousoffshore.com/forums/s...ad.php?t=15663
All above prob not absolutes, but good info/ideas/etc
09-20-2022, 07:52 PM
#65
i would search the threads about his set up, an awful lot of work was done to achieve that 30/35%, alot of bottom work to get it's running angle and alot of lake x time.
someone was joking about it as the million dollar scarab with the work, could've been him.
good reading for sure
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Twin O/B Sonic (09-21-2022)
09-20-2022, 07:58 PM
#66
bottle jack
Last edited by outonsafari; 09-20-2022 at 08:01 PM.
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Twin O/B Sonic (09-21-2022)
09-21-2022, 04:51 PM
#67
Registered
Talked to Kenny from Velocity and they recommend staggered if your running 110 or more in the 39. It keeps you from getting airborne. I removed some weight from my engine compartment and moved my toolbox and supplies from the cabin to the engine compartment and I run more trim than I used to in big water, so removing the weight moved the CG forward. In rough water you want the CG a lot more forward to keep the boat level. I run a lot in 3'+ in everything from a 16' Senza to my Velocity 280 and they both liked a full tank of gas otherwise you are pounding your brains out. The Senza had the fuel tank up front, may not have been the fastest but I could run in anything.
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03-01-2024, 11:53 PM
#68
Registered
I’ve done quite a bit w/rebalancing trailers to get proper tongue weight which is a great example of how much I have shifted weight in the hull.
Although I never checked tongue weight as purchased it did tow perfect at 80 mph on its way home.
Once the power conversion was complete it was scary to tow and swayed terrible!
I weighed the tongue at that point and was only 135 lbs!
Far from the targeted 10% of gross, loaded weight which is 4500 lbs.
Had to move hull as far forward as I could which was almost 2’ and got tongue weight to 450 and now tows great.
As to weight shift in small boats, I designed/built and raced outboard hydroplanes for 9 yrs so I totally get that.
I firmly believe I am as good as I am on trim buttons because I spent 9 yrs w/my ass being the trim buttons 😂
Also spent many yrs playing w/fast single OB hulls.
Although I never checked tongue weight as purchased it did tow perfect at 80 mph on its way home.
Once the power conversion was complete it was scary to tow and swayed terrible!
I weighed the tongue at that point and was only 135 lbs!
Far from the targeted 10% of gross, loaded weight which is 4500 lbs.
Had to move hull as far forward as I could which was almost 2’ and got tongue weight to 450 and now tows great.
As to weight shift in small boats, I designed/built and raced outboard hydroplanes for 9 yrs so I totally get that.
I firmly believe I am as good as I am on trim buttons because I spent 9 yrs w/my ass being the trim buttons 😂
Also spent many yrs playing w/fast single OB hulls.
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Twin O/B Sonic (03-02-2024)
03-02-2024, 12:14 AM
#69
Registered
Found some good Int.
Anything traveling in 2 different fluids (air/water) is going to be more complicated. Increased speed and choppy water ads to the complexity.
While knowing the working to the static CG helps, the dynamic CG is where it all comes together, and it always moves with speed.
https://www.aeromarineresearch.com/d...stability.html
Anything traveling in 2 different fluids (air/water) is going to be more complicated. Increased speed and choppy water ads to the complexity.
While knowing the working to the static CG helps, the dynamic CG is where it all comes together, and it always moves with speed.
https://www.aeromarineresearch.com/d...stability.html
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Twin O/B Sonic (03-02-2024)
03-02-2024, 06:14 AM
#70
Registered
Thread Starter
Interesting that you posted this as I am a friend of the author and was just thinking of reading up on it one of his books that I have.
THANKS!
And yeah, when the hull is light enough and has enough bow lift, it is a moving target.
The boat in that picture is an Allison (had one) and the guys w/the fast ones move sand bags (small, 2-5 lbs) around to balance the boat at speed!
Some of the prettiest vee bottoms at speed!
At an event I used to host, we had GPS runs.
Throw a handheld GPS in the boat and give drivers 15 mins to post a number.
Was held on the Ohio River and one yr in less than optimal conditions, for 500 lb hulls w/300 + HP.
Fastest boat was a Fla buddy in his STV tunnel boat at 128!
(Had been 144 in perfect conditions!)
He told me to give the award to the 2nd place boat which was an Allison at 126!
Was a magical moment as everyone else had run and were standing on the river banks waiting for this boats pass.
As he was rounding the bend in the river (@ WFO!) a barge was passing in front of us so we all knew he’d have to abort his run.
The barges knew our event was taking place and passed at an idle to reduce wake but it was still there.
So this guys bad ass Merc is echoing off the trees at 10,500, he catches the barge, then his wake and did not lift!!
Could have heard a pin drop on the shore line.
He passed us and that barge at 126, idles into shore and hands me that GPS.
I read the # to the gang and they thought they had just seen God walk on water!
That boat was balanced!
Then the drivers crew arrived w/a wheel barrel for his balls!
THANKS!
And yeah, when the hull is light enough and has enough bow lift, it is a moving target.
The boat in that picture is an Allison (had one) and the guys w/the fast ones move sand bags (small, 2-5 lbs) around to balance the boat at speed!
Some of the prettiest vee bottoms at speed!
At an event I used to host, we had GPS runs.
Throw a handheld GPS in the boat and give drivers 15 mins to post a number.
Was held on the Ohio River and one yr in less than optimal conditions, for 500 lb hulls w/300 + HP.
Fastest boat was a Fla buddy in his STV tunnel boat at 128!
(Had been 144 in perfect conditions!)
He told me to give the award to the 2nd place boat which was an Allison at 126!
Was a magical moment as everyone else had run and were standing on the river banks waiting for this boats pass.
As he was rounding the bend in the river (@ WFO!) a barge was passing in front of us so we all knew he’d have to abort his run.
The barges knew our event was taking place and passed at an idle to reduce wake but it was still there.
So this guys bad ass Merc is echoing off the trees at 10,500, he catches the barge, then his wake and did not lift!!
Could have heard a pin drop on the shore line.
He passed us and that barge at 126, idles into shore and hands me that GPS.
I read the # to the gang and they thought they had just seen God walk on water!
That boat was balanced!
Then the drivers crew arrived w/a wheel barrel for his balls!
Found some good Int.
Anything traveling in 2 different fluids (air/water) is going to be more complicated. Increased speed and choppy water ads to the complexity.
While knowing the working to the static CG helps, the dynamic CG is where it all comes together, and it always moves with speed.
https://www.aeromarineresearch.com/d...stability.html
Anything traveling in 2 different fluids (air/water) is going to be more complicated. Increased speed and choppy water ads to the complexity.
While knowing the working to the static CG helps, the dynamic CG is where it all comes together, and it always moves with speed.
https://www.aeromarineresearch.com/d...stability.html
Last edited by Twin O/B Sonic; 03-02-2024 at 06:22 AM.
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the deep (03-02-2024)
