Love this 11.9m Z-Bow Now Constructed It's The Biggest!
11.9 mtr Z-Bow in HDPE - The primary goal with this new build was to create a vessel that has high speed and exceptional handling whilst offering maximum passenger comfort and being more fuel efficient.
11.9 mtr Z-Bow in HDPE
Follow the largest HDPE vessel build in Australia. (At the time of writing) because has several unique qualities.
- Built with a Unique Z-Bow
- Has a Two Stepped Hull
- Is constructed in HDPE (High-Density Polyethylene)
- 1C Survey for 42 passengers plus 2 crew
- Skippered by a Coxswain

Objectives, So Why?
What was the primary goal with this new build 11.9 mtr Z-Bow? To create a vessel that has high speed and exceptional handling. Also, needed to offer greatest passenger comfort and, be cheap to run.


For this purpose, we constructed a 7.5 mtr two-step foam collar. Furthermore, she is constructed from aluminium and designed on spec as a test bench for a larger vessel. The results were astounding. A very fast vessel that can turn at high speed and yet still offers a very smooth and comfortable ride.
Would like to experience what your new people mover can do? To test drive this vessel, please call and I will organise.
Why HDPE?
- It has a lifespan of up to 50 years and a very low corrosion rate
- No Anti foul
- No Electrolysis
- HDPE is a thermoplastic material thus workable recycling is available
- Tough, flexible, and resistant to bumps and scratches. This means rocks and other sharp objects won't puncture it.
- The carbon footprint is five times lower than that of aluminium
- A HDPE hull is smooth, and it is completely resistant to marine growth
- This material does not have any chronic disease like delamination of GRP or “Osmosis”
- HDPE boat is lighter than aluminium and steel.
- 11.9 mtr Z-Bow has in HDPE has colour variety is available
11.9 mtr Z-Bow, what is its purpose?
Firstly, when the bow dips, the 'Z-Bow's designed for wave piercing. So this is to reduce vertical accelerations and increase pilot comfort. Furthermore, there is an underlying principle behind the Z bow, which is quite simple and easy to fathom. To not cause an increase in the weight or length of the vessel, the z-bow allows the hulls length to stretch and be finer. Lastly, the consequential end of this is that a vessel can pierce through waves. This of course beats crashing into them. Finally, this slight difference goes a long way in helping to have a smooth and efficient ride.
Ok, so what about the two Stepped Hull?
These hulls are uncommon. In Addition, they function by getting the air behind the steps. This is when they work in a displacement mode, therefore causing more efficiency.
Also, to provide higher levels of comfort and fuel efficiency. These boats can be more efficient and comfortable with stepped hulls. A stepped hull creates instead three short, wide, high-aspect surfaces. These are in turn far more efficient. This modified hull reduces its frictional drag on the water by creating a higher lift. Therefore, boats with a stepped hull are up to 15% faster than those with a standard hull. Stepped hulls distribute lift more evenly. So it is this that makes your vessel more level at higher speeds and with a consistent trim angle.
To explain, as the hull lifting surface aspect ratio increases, so does the efficiency. A single hull surface displaying a 1:3 aspect ratio (where the length is three times that of the width of the hull).

Lighter, faster boats benefit a lot from a stepped hull. Throughout the entire speed range, this results in lower fuel bills. Stepped hulls are more efficient vessels.
Specs of the 11.9 mtr Z-Bow being built
Measured Length - 11.99 mtr
LOA - 12.49 mtr
Beam 4.2 mtr
Draft - 0.55
Displacement (Lightship) 6,000kg
Displacement (Loaded) 10,600kg
Engines - 2 x 325hp
Fuel - 2 x 600ltr
Water - 200 ltr
Survey - 1C 2 plus 37
The Build So Far

I always love seeing a vessel at this stage.
It is the raw bones that will define the shape.
This needs to be perfect so the rest of the build can be perfect too.
18 mm Thick Bottom Plate is being cut and fixed.


Z-Bow is now starting to form
The two steps built into the bottom of the hull can be seen here.

The two steps built into the bottom of the hull can be seen here.
These pics were uploaded on 29/09/2022
I will be adding further updates as this build continues.

