Side-Power Stern Thruster Tunnel

Side-Power Stern Thruster Tunnel
Side-Power Stern Thruster Tunnel

Specification :

  1. Designed for SE30 and SE40 Side-Power Thrusters.
  2. Material : Composite, 30% Stronger than Fiberglass Stern Tunnels.
  3. Ready Bored, with Extension Harness for Control Box.
  4. Item # : 304834.
  5. Brand : Side-Power.
  6. Model # : SM90124i.
  7. Shipping Weight : 4.50 Lbs.

Features :

  1. Composite Stern Tunnel for SE30 and SE40.
  2. Ready bored, with extension harness for control box.
  3. Stronger and more accurate stern tunnels with added safety features.
  4. 30% stronger than fiberglass stern tunnels.


To achieve maximum effect, reliability and durability from your Sidepower Sternthruster, a correct installation is veryimportant. Please follow the instructions carefully, and make sure that all checkpoints are carefully controlled.

Make sure that there are enough space both inside and outside the transom of the boat.

Installation Side-Power Stern Thruster Tunnel
Installation Side-Power Stern Thruster Tunnel
Installation table Side-Power Stern Thruster Tunnel
Installation table Side-Power Stern Thruster Tunnel

Additional considerations for positioning of stern thruster.

  1.  Make sure that the stern-tunnel does not disturb the waterflow under the hull.
  2. Ensure that when installed the thruster does not foul exisiting equipment inside the boat like steerage links etc.
  3. It is essential that the motor is supported so that the total weight is not on the tunnel alone.
  4. Make sure that the water flow from the thruster are not intereferred to much by sterndrives, trimtabs etc. as thiswill reduce the thrust considerably.
  5. It is possible to mount the tunnel off the boat’s centre line if necessary.
  6. If the stern thickness is to much for the thruster in question you can easily remove material in the necessary areato fit the thruster. The stern thickness even here will never have to be less than the max. measurement given asmax. stern thickness.


  1. Once the place for the installation has been decided, hold the tunnel in place in the horizontal position and mark the bolt holes. Remove the tunnel and it is then possible to calculate and mark the centre.

  2. It is important that the tunnel flange sits flush on the transom. If this is not case, then the fitting area on the transom will have to be worked to ensure a snug fit. PS ! Take care with grinders as it is very easy to remove to much fibreglass At this time, cut out the centre hole and the transom to the same internal diameter as the tunnel flange and drill the bolt holes. Before actual fitting the stern tunnel, we recommend that the prepared area is sealed with a gelcoat or similar to ensure there is no water ingress.

  3. Before fitting the tunnel to the transom, install the gear leg to the tunnel as described in the thruster installation manual. We recommend that you fit the oil feed pipe also before the tunnel is bolted to the transom. Special installation points described on page.

  4. When fitting the tunnel, ensure that there is ample sealant (Sikaflex or similar) in the sealing tracks of the tunnel flange and around the bolts to make a water tight fitting (see FIG. 2&3). Bolts, washers and nuts are not included as they will vary depending on the transom thickness. We recommend A4 stainless with A4 lock nuts and A4 washers of a large diameter on both outside and inside. Bolts diameter (stainless steel) :
    ø 6mm or 1/4” for SE 40 & SE 60.
    ø 10mm or 3/8” for SE 60/SE 80/SE 100/SE 120/SE 130/SE 150/SE 170/SE 210/SE 285, SH 100/SH 160/SH 240/SH 300.
    ø 12mm or 1/2” for SH 420/SH 550.

  5. The electromotor must have a solid support so that the weight can not cause a twisting action on the tunnel (see FIG. 4).

  6. Refer to the installation manual for the recommended thruster fitting.
Bolt on installation of Side-Power Stern Thruster Tunnel
Bolt on installation of Side-Power Stern Thruster Tunnel


  1. Cut of the bolting flange on the stern-tunnel.
  2. Grind off the gelcoat both inside and outside theremaining “tube” atleast 10 cm down on the“tube” (see FIG. 5).
  3. Offer the stern tunnel to the desired position onthe transom and mark around the tube.
  4. Cut the marked hole in the transom of the boat.
  5. Grind off the gelcoat on the transom of the boat inan area of atleast 10 cm / 4” around the hole, bothoutside and inside (see FIG. 5).
  6. Offer the stern tunnel to the transom in the desiredhorizontal position, then bond to the transom withmulti layers matt both inside and outside (see FIG.6). Take care not to reduce the internal diametermuch, as this will make it more difficult to mount the thruster.

  7. Apply gelcoat or similar on all bonded areas.

  8. Install the gear leg on the stern-tunnel as de-scribed in the installation manual for the thrusterbut fit the oil feed pipe first. Special installation points described on page 7 ofthis manual.
  9. The electromotor must be sturdily supported sothat the weight-arm tension from the motor weightare not applied only on the tunnel (see FIG. 4).

  10. Basic installation of the flexible coupling, motorand electrical installation are described in thethruster manuals.

    Mould installation of Side-Power Stern Thruster Tunnel
    Mould installation of Side-Power Stern Thruster Tunnel


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