Hydroplane Measurements

[FlyinFinn]

I am looking to better understand the dimensions that RC Unlimiteds lists in their boat registry pages. Specifically, is there a diagram somewhere that shows where the various measurements are taken on a hydroplane? More specifically, what is "A.P.L." and "P.F.D."? How is hull depth measured? What is the tunnel measurement that is referred to? Also, it appears that the actual dimensions are listed with a 1/8 scale converted measurement or acceptable scale range for the measurement included. Is that basically correct?

 

[wayne middlemiss]

After plane length
Pickle fork depth

 

[FlyinFinn]

After plane length
Pickle fork depth

Thanks Wayne. Could you explain how to measure these parameters?

 

[FloridaScaleBoater]

After plane is measured from the sponson transom to the boats transom.
Pickle Fork Depth, from the FWD tip if the sponson to the leading edge of the center section
Tunnel width is measured between the 2 sponsons, on the bottom of the hull.
Hull width is at the hulls widest point, usually taken at the aft end of the sponsons

 

[Hydro Junkie]

Nice job, Rick. I've only got two things to add.
The first one is hull depth. This isn't a major measurement but some people do check it when checking to make sure a new hull meets the hull roster measurements. This one is a measurement from the rear bottom of the boat to the highest part of the deck, normally also at the sponson transom.
The other one is something that has some confused is afterplane length as compared to hull length.
As Rick said above, the afterplane is the length between the sponson transoms and the rear transom. What causes confusion is when the boat being modeled has extended hydro shoes at the rear. The distance between the furthest part aft of the shoes and the hull's transom is not counted as afterplane length, but is included as part of the overall length. This isn't a big deal on most boats. The problem is with the newer style of turbines and the 1991 Miss Madison all of which have a significant length on the shoes. The Madison is actually 26" from transom to the rear of the shoes. If you're looking at building a boat to race, you might want to check the tech inspector to make sure your boat will be legal when it's done

 

[GraysonTaylor]

Hi Mark, If you have any pictures of the 91 transom they would help me out.

 

[GraysonTaylor]

There is a post 91 Valvoline Madison help, that has some good pictures of the 93 Frosted Flakes transom. Thanks Greg for posting those.

 

[Greg Wannamaker]

I was surfing around in the MHR last night and found that the 91 Madison and 93 day glow Frosted Flakes was the same boat. Wish I had my boat back together to show you all the detail but am a few weeks away from that. It got ran over awhile back and am in the midst of full repairs.

 

[Hydro Junkie]

Hi Mark, If you have any pictures of the 91 transom they would help me out.

I think so, won't be able to really check for a couple of days.

 

[FlyinFinn]

Nice job, Rick. I've only got two things to add.
The first one is hull depth. This isn't a major measurement but some people do check it when checking to make sure a new hull meets the hull roster measurements. This one is a measurement from the rear bottom of the boat to the highest part of the deck, normally also at the sponson transom.
The other one is something that has some confused is afterplane length as compared to hull length.
As Rick said above, the afterplane is the length between the sponson transoms and the rear transom. What causes confusion is when the boat being modeled has extended hydro shoes at the rear. The distance between the furthest part aft of the shoes and the hull's transom is not counted as afterplane length, but is included as part of the overall length. This isn't a big deal on most boats. The problem is with the newer style of turbines and the 1991 Miss Madison all of which have a significant length on the shoes. The Madison is actually 26" from transom to the rear of the shoes. If you're looking at building a boat to race, you might want to check the tech inspector to make sure your boat will be legal when it's done

Thank you, much appreciated!

 

[FlyinFinn]

After plane is measured from the sponson transom to the boats transom.
Pickle Fork Depth, from the FWD tip if the sponson to the leading edge of the center section
Tunnel width is measured between the 2 sponsons, on the bottom of the hull.
Hull width is at the hulls widest point, usually taken at the aft end of the sponsons

Thank you!

 

[Hydro Junkie]

This is one I took years ago, would have to do more looking to see if I have any more

 

[Hydro Junkie]

I found more but they are all BMP files which, unfortunately, won't post to the forum

 

[GraysonTaylor]

You might be able to do a "save as" in your program.