Prop strut, rear mounted or underneath?

[Jake Ellwood]

Hi all,

Only me with another hydroplane question - sorry, there are going to be a lot!

I noticed in some recent youtubing while it was quiet at work that almost, if not all of the Hydroplane builds (American youtuber if that makes a difference) had the prop strut mounted to the bottom of the boat rather than the transom, like I always have done and seen on boats here in Europe.

Is this an American thing? Or is there a reason why it's like this on hydroplanes? Does it make a difference?

Very curious to know!

Thanks very much in advance.
Jake

 

[FloridaScaleBoater]

If you are building to run in 1/8 scale or gas scale it is required to be through the bottom of the hull (NAMBA & IMPBA Rules)
Sport hydro allows either way. Hope this helps.

 

[Jake Ellwood]

Fantastic. Good to know. Thanks very much!

 

[Jerry Dunlap]

If you are building a sport hydro it is a whole lot easier to mount the strut on the transom. Also much easier to make strut adjustments.
JD

 

[Hydro Junkie]

On this one, Jake, I would suggest you check with people that run boats in your area. The rules in Europe are probably very different than here in the US so we may be giving you some bad information and, since it's how we do things here, we wouldn't know the difference

 

[Jake Ellwood]

Appreciate that, HJ. However, I don't intend on racing this one. Just fun at the lake with friends. Kinda tempted to put the strut through the floor for something different and as a learning experience. Will think on it

 

[Samuel Hagan JR]

If it’s just for fun transom. Much better easier.

 

[LohringMiller]

Mark Anderson and Eric Bourlet tested inboard versus outboard strut mounting on identical Mutt Sport 40s. The could find no difference in performance when they raced them together around a course. It's easier to mount the strut outboard on the transom as was noted above.

Lohring Miller

 

[Mario Johnston]

I set up my sport 40 to have the strut exit the bottom of the hull, but I also have the option to transom mount out as well just by flipping the brackets, should I decide to.

 

[P THOMAS]

Mario that Supersport45 boat dont like rear mounted strut. hard to launch and will run too loose and blow off.
The newer Stealth 45 boat like the rear strut

 

[Mario Johnston]

Youre not wrong, Phil!
I went ahead and ran it this way but im so happy with how it runs, I have no need to change it now! Maybe talking to you about a Stealth hull in 2021 that's for another thread though!

 

[Samuel Hagan JR]

The way Mario has his setup is the way to go for under hull strut setup.

 

[Jake Ellwood]

Sorry for not replying to this any further everyone. Thank you all for the input. I went for transom mounted strut. As others mentioned, its easier