Optional equipment is defined as any system or equipment, which is not part of the submersibles basic fit. In other words, none of the optional equipment listed is required as part of obtaining ABS approval or safely operating the Triton or Discovery.
The ability to track a submersible underwater while not required by ABS, the USCG or the CI Registry is without question a desirable and important safety feature for any deep diving manned submersible. The two most common methods used are Ultra Short Base Line (USBL) and Long Base Line (LBL) tracking systems.
Ultra Short Base Line (USBL) tracking systems use two-way acoustic communication to calculate the relative position of a surface vessel mounted transceiver to an underwater vehicle mounted beacon. The surface vessel transceiver sends a command to a sub sea beacon triggering a transmission response. When the surface vessel transceiver receives a response from the sub sea beacon the content of the signal is decoded. In addition, phase and delay measurements are used to calculate the sub sea beacon’s coordinates relative to the surface vessel transceiver (range and bearing).
USBL tracking systems calculate the relative position of a sub sea object to the surface vessel transceiver by interfacing acoustic range and bearing data to attitude (motion), heading and GPS sensors.Link Quest is a relative new comer to the USBL business and first began selling systems only about six or seven years ago. However, Link Quest is the largest supplier of acoustic modems in the world and it is due to the considerable innovations they have brought to this area of underwater communications that they were able to enter the USBL market with a product that trumps their competitors by a considerable margin both in terms of cost and capability.
As discussed earlier, the accuracy of the positioning information obtained from the USBL system is directly related to the quality of the motion and heading sensors interfaced to it. Normally, USBL manufacturers recommend using expensive motion sensors.
However, the cost for these sensors can be prohibitive (often in excess of $25,000) and since tracking of the Triton may be performed from a RIB, it makes sense to consider some of the less expensive alternatives. Our quote includes a very capable motion sensor manufactured by MTI.
Another capability afforded by the Tracklink 1500 USBL system is the ability to add an acoustic modem. Text messages and images can be sent to/from the RIB by the submersible at approximately 9,600 baud but most important of all an acoustic modem provides a back up communication capability. In the unlikely event of a primary through water communication or underwater telephone (UWT) system failure, the submersible retains the ability to communicate with the surface.
We recommend a Panasonic Toughbook laptop computer for the RIB in order to interface to the sensors and display the relative position of the submersible on a chart or grid. We have allowed a budget of $5,450 for this lap top computer including our integration fee of $900. If the client intends to track the submersible from a RIB, we recommend the Tracklink 1500 LC. Further, we recommend the use of the MTI motion sensor and the Panasonic Toughbook computer with HYPACK software loaded on it. Finally, we feel the acoustic modem feature is worth considering because of the added capability and additional safety it offers.
Originally, DVL equipment was big, expensive, and required large amounts of power (often in excess of 50 watts). The demand by the underwater vehicle industry for smaller platforms led to the development of compact, inexpensive and efficient DVL systems.
A modern DVL provides a variety of instrumentation capabilities in a single package including velocity (both vertical and horizontal), heading, depth, altitude, temperature and current measurement.
A DVL measures speed relative to the bottom provided the submersible is in water depth within the capability of the unit (in the case of the Link Quest NavQuest 300, the unit is capable of tracking the bottom in water depths to 300 meters.
Interfaced to the HYPACK Navigator software loaded on to the Discovery Panasonic writing tablet PC and working together with a GPS sensor (on the surface), the DVL ensures accurate positioning of the submersible is known by the pilot at all times. On the surface, the Hypack Navigator system software accepts regular updates from the Panasonic writing tablet PC’s integral GPS sensor. Once the Discovery dives and the RF link to the GPS receiver is lost, the system automatically switches to accepting velocity (speed and direction) inputs from the Link Quest NavQuest 300 DVL. In this way, the pilot always has a plot of the exact position of the submersible on a grid with the latitude, longitude, depth, heading and altitude constantly available.
Up until recently, this capability was simply not possible or was so prohibitively expensive as to be available to those with military budgets. The advances made in sub sea electronics and acoustics as part of the Remotely Operated Vehicle development makes it possible for us to offer a system with these powerful and important navigation capabilities for an affordable price.We recommend the Link Quest NavQuest 300 DVL equipped with a depth sensor.
A manipulator is an underwater arm attached to the bow of the submarine that allows the operator to pick up objects from the bottom and examine them and either replace them or put them in a specimen basket.
Although there are a number companies that manufacture manipulators, none of them offer a low cost system as capable and proven as those from Hydrolek. For the Discovery we recommend the Hydrolek HLK-CRA6 manipulator, valve pack and control box. However, we don’t recommend using the HPU offered by Hydrolek and instead suggest using a brushless motor driving HPU from Tecnadyne (the same company supplying the thrusters on the Discovery). According to ABS, the manipulator system must be jettisonable, which means both a guillotine (for hoses and cabling) and an ejectable bracket are required.
While the Triton is equipped with a high quality external lighting system an upgrade is available. High intensity discharge (HID) lighting systems have been around for many years. We have researched and are familiar with the HMI/HID lights available from a wide range of well-respected companies.
The combination of DSPL’s excellent reputation, the quality of their products combined with their favorable pricing and our personal experience make them our first choice.
DSPL introduced the Super Sea Arc 150 HID light in 2006. HID lights offer the highest efficiency in underwater lighting today (next to high output LED), which is an important consideration for a manned submersible with a finite amount of stored energy on board. Also, HID lights provide light with the correct color temperature (i.e., closest in appearance to actual sunlight).
SONAR is an acronym for Sound, Navigation and Ranging just as RADAR is an acronym for Radio Detection and Ranging. SONAR systems have made incredible advances during the last decade and we are fortunate to have a wide selection of inexpensive yet highly capable systems available.
There are many different types of SONAR sytems including those designed for obstacle avoidance and imaging. For the Triton, we generally recommend color imaging SONAR systems only as the obstacle avoidance and CTFM SONAR systems are simply too expensive. In addition, the slow speed and excellent visibility afforded by the Triton make the need for obstacle avoidance type SONAR systems largely unnecessary.
There is a wide assortment of color imaging SONAR systems available for small manned submersibles. We recommend the 881A from Imagenex.
The following is a list of the most popular optional equipment we recommend as part of the purchase of a Triton or Discovery:
1. USBL tracking system with acoustic modem (Link Quest)
2. Manipulator system/HPU (Hydrolek/Tecnadyne)
3. DVL (Link Quest)
4. HID external lights x 2 (DSPL)
5. Color imaging SONAR system (IMAGENEX)