MARINNO maritime innovations GmbH & Co KG

Mounting EXTURN bow thruster

Boat type: Beneteau 43
Model EXTURN 300
Mounting set: adapter
Date: 30.03.2009
Location: Yachtwerft Heiligenhafen GmbH & Co KG - Warteburgweg 5 - D-23774 Heiligenhafen

Step 1: Choise of mounting position and measurement
To get the optimal efficiency with EXTURN as a bow thruster, the position is very important. It is positioned as deep as possible and also with attention to the optimal position in the front of. 30 cm under the waterline is adequate for the full capacity.

EXTURN should be positioned exactly on the boat axis. While measuring mind on the position, so that the needed whole of 50 mm isn’t placed unfavourable (e.g. bulkhead).

Step 2: Main drilling
A cross section dimension of 50 mm is used for the drilling of the quill shaft. Afterwards the height of the drill hole is exactly measured (20 mm). The number of the used gaskets depends on the height of the hull, because they get compressed about 25% while screwing.

Formula: Sealing Height: (hull size + 10 mm) x 1.5
The absolute sealing height for the Beneteau 43 as follows: (20 + 10) x 1.5 = 37.5 mm

Step 3: Measurement adapter position and projection
The position of the adapter is measured exactly…
… and finally drawn on the hull by constraining the adapter on the hull.

Step 4: Grinding the projection
For the optimal grip of Sikaflex – when fill out the possible distance between the adapter and the hull – the projection of the adapter was grinded. (see Step 8).

Step 5: Transaction of EXTURN bow thruster
The EXTURN-cable could be conducted through drill hole and provisional bolt down with the attached adapter.

Step 6: Indication and drilling mounting pins
First the positions of the mounting pins are indicated, thereupon EXTURN can be twisted and the drillings with a cross section dimension of 18 mm can be done.

Step 7: Screwing and sealing
Now EXTURN can be screwed finally. Initially the bow thruster is sqeezed on the hull with a spile, to get the counter pressure for screwing. Afterwards the rear side of the mounting plate is coated with Sikaflex. However don’t press the coated mounting plate manual on the hull, because it will be formed self-contained while screwing.

Afterwards the used numbers of gaskets are attached, two plain washer disposed and EXTURN by using two hex nuts firmly bolt down. The gaskets get compressed and fill out the drill hole completely. Unimately the two mounting pins were also screwed with these gaskets.

(Add on: The included isolation disc is used in cases of hulls made of steel or aluminium instead of the mounting plate.)

Step 8: Fill out the adapter distance with Sikaflex
To complete the mounting of EXTURN the minimal distance between the border of the adapter and the hull is filled out with Sikaflex. The absolute mounting time of EXTURN is only 50 minutes!

Step 9: advice sticker for the crane operator
After finishing the mounting of EXTURN the advice sticker for the crane operator have to be placed on both sides of the hull very popular. The EXTURN bow thrusters should also be treaded with the antifouling next time.

Step 10: Electrical installation
After competition the mechanical installation the electrical installation will be the next step. Through easy-to-handle plug and play connectors EXTURN will be combined with the main relay and the main relay with the control box – called E-BOX.

The main relay is connected to the battery (12V or 24V, depending on the model). Marinno as the producer of EXTURN recommends a separate battery (for example: Deep-Cycle-Batterien, Optima BlueTop, 55 Ah), positioned next to the bow thruster to avoid voltage loss and keep the required cable dimension as small as possible. It’s also necessary to integrate a circuit breaker and an assurance in the wire harness.

The E-BOX makes it possible to connect up three operating controls coeval to three designated slots.

The complete installation of EXTURN (mounting and electrical installation) is done within one day. One more benefit compared to the traditional bow thrusters next to the optimal efficiency, the minimal demand of space and the minimal audibility

For more information, visit

Exhibitor Data Sheet