Wild Thing 26" - Tuning help needed.


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Luis Oliveira

May 6, 2019
Hi All,

I've built a 26" Wild Thing (scaled down from the 32" original John Finch design) and I am now testing it.

First, I have to say that my experience with boats is very limited. I started with one of those chinese FT009 boats and I got instantly hooked. I modified it a bit, ( added an aluminium rudder, and a 1/8 shaft that allowed me to use some different props) but it's size and solid shaft limited it to around 20mph. By then, wanted more speed, so I used my previous experience in building planes and started building some boats.

I first built a Kep's 2S outrigger hydro (18") which runs very well (around 37mph, but still testing). Then I wanted to build a bigger Mono. I chose John Finch's Wild Thing, but scaled down a bit, I didn't want to go full 32" off the bat, since I am new at this.

I started with a small prop (x435) and worked my way up to the biggest prop I had in hand, which is a grapner k42. It now has decent speed and rides well in glass water, but once I hit my own wakes, it chine walks badly and wants to blow over.

The boat specs are:
Length: 650mm (26")
Weight: 1700g (3lbs & 12oz)
Motor: Boat Rocket 3660 2600kv (28000 rpm unloaded)
ESC: FlyColor marine 90A
Batts: 2x Turnigy 3S 2200mAh in parallel
prop: Graupner K42
strut: 4.8mm (3/16") up - 8.8mm (11/32") from bottom of the keel to center of prop shaft

See it in action here:

I set it up as Mr. John Finch himself advised for starting tuning a new boat: CG at 29%, trim tabs up, strut level.

I now wanted some advice on where to go from here. Should I bet on:
- Another prop? (what is the typical prop for this type and size of boat?)
- move the CG forward?
- drop the trim tabs?
- raise the strut?

I know from what I read that all of the above will most likely improve the handling. What I don't know is where to start. So I would very much appreciate your advice.

Some pics of the boat below. Later on, if someone is interested, I could post a build thread.

Thanks in advance.
Last edited:

Luis Oliveira

May 6, 2019
What I can establish, My boat is getting airborne and getting buut first in the water, Is it? look closely.

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