2021 Parker Enduro

[CUDA]

Ever check for center of gravity?

It's easy. Of course, you'll need a commercial drive-on scale, or some other way to measure your weights.

(1) Weigh your trailer empty. Record the weight readings at the axles, and then at the tongue. With this you can get the CG of the trailer by itself.

I'm just making up numbers here, but let's say you get 1800# at the axles and 200# at the tongue. Therefore, your trailer weighs 2000#.

The CG is going to be 10% (200 [light end] / 2000 [total]) of the distance from the heavy side (the axles).

Or conversely, 90% (1800 [heavy end] / 2000 [total]) of the distance from the light end.

So, let's say it's 20' from the axles to the tongue. Your CG is 2' from the axles, or 18' from the tongue.

Either way you do it, it will work out the same.

(2) Repeat the weighing with the boat on it this time. Again, record the weight at the axles and at the tongue.

Do the same math with the new numbers to arrive at the CG position of the trailer-boat combo.

Let's say it was 7,800# at the axles and 2,200# at the tongue. The total is 10,000# (2,000 Trailer, 8,000 Boat).

The CG from the axles of the combo would be 2,200 / 10,000 X 20 = 4.4'

From knowing those two positions you can precisely calculate where the boat's CG is.

(3) We're going to do a summation of moments at the axle position, I'm calling that the zero position.
(A moment is also known as a torque expressed as Distance X Force[Weight], i.e. FT-LB, IN-LB, etc.)

So, the moment generated about the axles by the boat-trailer combo is 10,000# X 4.4' = 44,000 FT-LB

We know that the moment generated by the trailer alone is 2,000# X 2' = 4,000 FT-LB

So, from that we can compute that the necessary moment that the boat needs to generate is 44,000 - 4,000 = 40,000 Ft-LB.

Thus: 40,000 FT-LB = 8,000# X the distance from the boat's CG to the axles.

40,000 / 8,000 = 5 FT.

So, in this example the distance from the axles to the boat's CG is 5 feet.











Set back will help more than anything.

[Baker343]

Ever check for center of gravity?

It's easy. Of course, you'll need a commercial drive-on scale, or some other way to measure your weights.

(1) Weigh your trailer empty. Record the weight readings at the axles, and then at the tongue. With this you can get the CG of the trailer by itself.

I'm just making up numbers here, but let's say you get 1800# at the axles and 200# at the tongue. Therefore, your trailer weighs 2000#.

The CG is going to be 10% (200 [light end] / 2000 [total]) of the distance from the heavy side (the axles).

Or conversely, 90% (1800 [heavy end] / 2000 [total]) of the distance from the light end.

So, let's say it's 20' from the axles to the tongue. Your CG is 2' from the axles, or 18' from the tongue.

Either way you do it, it will work out the same.

(2) Repeat the weighing with the boat on it this time. Again, record the weight at the axles and at the tongue.

Do the same math with the new numbers to arrive at the CG position of the trailer-boat combo.

Let's say it was 7,800# at the axles and 2,200# at the tongue. The total is 10,000# (2,000 Trailer, 8,000 Boat).

The CG from the axles of the combo would be 2,200 / 10,000 X 20 = 4.4'

From knowing those two positions you can precisely calculate where the boat's CG is.

(3) We're going to do a summation of moments at the axle position, I'm calling that the zero position.
(A moment is also known as a torque expressed as Distance X Force[Weight], i.e. FT-LB, IN-LB, etc.)

So, the moment generated about the axles by the boat-trailer combo is 10,000# X 4.4' = 44,000 FT-LB

We know that the moment generated by the trailer alone is 2,000# X 2' = 4,000 FT-LB

So, from that we can compute that the necessary moment that the boat needs to generate is 44,000 - 4,000 = 40,000 Ft-LB.

Thus: 40,000 FT-LB = 8,000# X the distance from the boat's CG to the axles.

40,000 / 8,000 = 5 FT.

So, in this example the distance from the axles to the boat's CG is 5 feet.











Set back will help more than anything.

You are absolutely correct on the CG. It is easier to balance a purpose built light race hull vs a ski hull that I was lucky to find for 2k. Part of the fun is taking a performance ski hull and try to make it somewhat competitive.
It brings family and friends together for some good times.

[Noah Burns]

I mean, appropriate type hulls for this race are littered all over the country, it's not like it's hard to find something. I get it, run what you already have but if you feel it's a safety concern then I would look elsewhere.

If you have a ModVp tree growing in your back yard
will you pick me a 20' Stoker easy on the sauce

[Baker343]

[Baker343]

Keith, have you guys considered tunnel extensions like the Stokers have? At one point we had even tried trim tabs where the tunnel tabs went, so you could make changes to tabs on the fly.

Keith always appreciate your input and experience running this race. I believe only Johnny's Rampage the #1 or 2 out of the mold. They put a insert in the mold to allow for trim tabs. Jerry built the rest without this space (ski hulls). Because of the transom design, there's no space to mount a small block of aluminum to the transom just above the tunnels to add trim tab plates.
Depending how these mods work in testing, we may have to flip it over next year and add 3/4 to 1" to the top of the tunnels and allow a space at the end near the transom for trim tab plates and may run a flat center pad like others run.
I've done a lot of research and measurements of the different tunnels on hulls like Stokers, Laveycrafts, STV's, Mirages, HST's and Eliminator Daytona's. When Jerry Baker built my blue hull (use to be red when Delbert raced it) he allow space for trim plates and they modified the center pad from being slightly rounded to flat. It also has 7" tall tunnels at the end. Most of the ones I mentioned have 7 to 6 1/2". Some have 1" of squish and some 2 like STV's. Will you be at the F1 race in Havasu?

[Baker343]

Ain't purrrtt but she's solid and hasn't been beat to crap like most race layups of the early 80's

[Baker343]

We flip and sanded the bottom straight when we first got it

[STV_Keith]

Will you be at the F1 race in Havasu?

Sounds like you did your homework already, as I figured. Yes, we'll be in Havi for the F1 weekend. Staying at Crazy Horse.

[CUDA]

How wide is that pad above?

So many California boats of that era had such a similar design, Sleekcraft looks much like this below,

Who was the first that everyone copied?



I know Sleekcraft was very involved in jet boat drag racing back in the late 70's 80's

[Baker343]

How wide is that pad above?

So many California boats of that era had such a similar design, Sleekcraft looks much like this below,

Who was the first that everyone copied?



I know Sleekcraft was very involved in jet boat drag racing back in the late 70's 80's

Didn't measure pad width. I'm guessing 10 1/4 to 10 3/4"

[Baker343]

[Baker343]

Mr Duff Daily

[Baker343]

[Chaz]

Mr Duff Daily

Hey , I seen that guy the other day ... I just don't remember where ...

[Baker343]

20' Baker Rampage 2020 4hr Parker Enduro