TRIM INTERCEPTOR
Other companies have developed systems consisting of plates which descend ver tically parallel to the hull shape or parallel to the deck, which means in a completely horizontal way. The differences between the systems are based on the use of one or more pistons to perform this movement, or as in the case of the mechanism developed by Maritime Dynamics and Vosper Thornycroft which is equipped with a rotary horizontal axis which is what thrusts the vertical pistons with its circular movements which “inserts” the plates until they intercept the water. According to some specialists, the circular movement of the upper part involves major smoothness and precision movements. Never theless, the most refined system is the one developed by the Swedish trademark, Humphree which belongs to the Profjord AB company, whose name is also a play on words and uses the motto, hump-free to highlight the stability in the navigation which its system implies. In this case, it involves two cases, one for each side of the ship which contain two rigid plates with composite materials. These plates can be thrust upwards in the desired dimension to intercept the water flow and consequently correct the ship’s consolidated balance in the same way as the above described systems. These plates descend in the degree desired by the Skipper to intercept the water flow and consequently correct the ship’s consolidated balance as mentioned. In reality, the plate located more to the stern is the one that works so that the second plate, in the rear and shorter, operates as reinforcement for the first.

The system lacks hydraulic pistons and other external mechanisms; it is attached in the transom by means of screws and only requires an additional perforation in the hull for the passage of the servomechanism. The size which it occupies inside the hull is minimum, no larger than a shoebox, and the ser vomechanism is where the electric cable is connected which conveys the commands, in the form of electronic impulses which arrive from all of the steering stations on board the yacht. One of the features of the Humphree system is that the plates do not necessarily have to be straight instead they can have a curve shape which means they can be adapted to the shipbottoms with tunnels, which multiplies their usage options. The system is very easy to handle, since the switches are located on a small panel which also contains a high resolution LCD screen which displays a multi-function screen which repor ts, among other parameters, the position of each one of the inceptors at all times. It is possible to mount as many control panels as the steering stations which the ship possesses. Likewise, when the system is disconnected all the interceptors return to their highest positions, which means, where they don’t work. Thus, when the system is star ted up again, it is not necessary to verify the position of these appendages, since they always star t from the home position.
It is worth mentioning here that these mechanisms can also be mounted vertically, on several appendages similar to rudders, but fixed, so that the interception of the flow generated by the ship’s advance also serves to change course, but this corresponds to another article. Humphree has also developed software to automatically trim the ships, under the denomination ATOS (Automatic Trim Optimisation System), so that the computer is in charge of inser ting each of the installed plates to a greater or lesser degree in order to achieve the required stability in a completely automatic way with exceptional quickness. The Swedish Company offers up to sixteen different sizes for the interceptors, ranging from 750 to 1,500 millimetres, which can be mounted in series, combining several of these lengths. The price oscillates from 4,200 euros for standard system to 10,000 euros for equipment with the ATOS system. Humphree has mounted this type of systems in model series such as AB 88, Azimut 98 Leonardo, Leopard 24 m, Pershing 115, and various Mangusta models, or in emblematic yachts such as Wally Power or Fortuna.

QL BOAT TRIM SYSTEM
QL achieved its popularity when it adopted the trademark with a major market share, Volvo Penta. Volvo signed an agreement with Humphree to develop and commercialise the system under the denomination QL Boat Trim System. In this case, it involves two cases, one for each side of the ship which contain two rigid plates with composite materials. They have dimensions which are more limited than the systems mentioned above since they are destined for the general public. The system is super-easy to install, since it also does not require hydraulic pistons or servomechanisms. It is attached by means of screws and only requires a small perforation exactly in the place where each one of the cases is mounted in order to connect the electric cable which conveys the 12 or 24 volt electrical power required for its operation to the mechanism. The system allows the placement of operation switches in all the steering stations on board the yacht. The electric parts of each of these cases have been sealed for life. Volvo builds these par ts in two dimensions, with a length of 300 and 450 millimetres, both with a height of 100 millimetres so that one or the other can be used depending on the boat size, but several of them can be installed in series, mounting two units with the same size or mounting a large and small one on each side. With two parts of the QL 450 model on each side, it is possible to trim a yacht up to 50 feet in length, which means that this system has an extensive application field.
The advantages of this system in relation to flaps are the absence of the hydraulic piston, and consequently fewer par ts in the stern. We also highlight that it involves a mechanism made of a composite, which is consequently rust-free, thus resulting in fewer maintenance tasks. Another feature to bear in mind is that its reduced size makes it compatible with the height adjustable bathing platforms, which are currently in fashion, since fitting all these aspects into the stern is not an easy task. Furthermore in this case, when the engines are halted, the system is in charge of automatically collecting the interceptors so that when one starts to handle them they always start from the home position.
The QL Boat Trim System comes with a small control panel which contains all the switches for its usage and the indicators required for its comprehension, in the form of luminescent diodes. The system’s price ranges from 500 to 1,200 euros, depending on the number of interceptors and control panels installed, not including installation and taxes.