Page 8 - Arrow Shark 2020 RC Boats

Prop Thrust Angle Adjustment Tip

This adjusting tip works for most of Arrow Shark scale drives such as M8 outdrive, Blade-X Arneson S-Drive,
SRD-V2 Stingary Drive, X-Partner Mystic Surface Drive and Formula-X Outboard Drive.

Adjusting the angles of your surface drive and is part of the fun of driving your boat, and you can fine
tune it for best performance in varying conditions. The objective is to have your boat running with the
least amount of hull touching the water but still retaining stability.
The less of your hull that touches the water, the less drag and the higher speed. But with too little hull
in the water, the boat will become less stable and could overturn. If there is too much hull in the water
so the bow (ie the front) is running low, the boat is said to be running "wet". If the boat is too light on
the water with only a small length at the back in the water, it is said to be running "loose".
Before adjusting the thrust angle of your drive, you need to check that your boat is correctly balanced.
For monohulls, that is usually between about 27% and 30% of the length of the boat from the transom.
So if you have a 47inch boat, it should balance between 11.75 and 14.1inches from the back. Too
bow-heavy and your boat will run "wet" and could be twitchy and difficult to steer. Too stern-heavy
and the boat could be unstable or run with the bow rising and falling which is called "porpoising".
Your boat has been correctly balanced by the factory for the assembled RTR version, but if you
change the layout of any of the components that could affect the balance. Re-position components or
add weight to regain the correct balance point.
If your boat is correctly balanced and still runs "wet" or with most of its hull length in the water, or if
it sits too low at the back, you can tune the hull to run correctly by adjusting your prop angle (ie the
surface drive unit) or Trim Tabs.
These two techniques are inter-related and you need to try one thing at a time to see the effect it has.
Make small changes only - just a degree or two - then try again to find the result.
Angling the prop up will lift the front of your boat - generally resulting in less hull in the water and
faster speed. Angling the prop too high though will cause instability and the prop may "ventilate" or
spin without gripping because it's too close to the surface.
Angling the prop down will lift the back of the boat and keep more hull in the water-generally giving
more stable running but with less speed.
Trying different prop angles will find the one that works best for your boat in different water
conditions. To start with, run a straight edge along the bottom of the boat projecting out the back, and
set the surface drive unit so the prop shaft is parallel with the straight edge.

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