Buoy FAQs

Yes, both the OTR-300 and 600 series buoys are self-righting.

The current construction technique does not allow for battery replacement in the field. Most customers do not want responsibility for the sealing of the buoy to be left to their field personnel. Instead, after 2-3 years of operation, the customer sends the buoy back for a complete rebuild. We have moved away from rechargeable batteries with solar panels to using primary batteries that have a multiple-year shelf life and higher Ah capacity. Some customers require non-lithium type batteries due to environmental issues in the waters the buoys are deployed. We can offer both alkaline and lithium batteries to fit the customers needs. Battery type obviously affects buoy life. If a significant customer requested replaceable batteries, we would certainly offer such a modification.

We currently offer the buoy “engine” packaged in a waterproof case that can be serviced in the field. The case is designed to be attached to a floating object above the waterline — not to float in the water itself.

The OTR-300 (with alkaline batteries) will send approximately 10,000 messages over a 3-4 year period. The OTR-600 can send approx 400 messages over a 28-week period. These are conservative numbers derived from the power calculation program provided by Inmarsat.

Our real-world experience is being closely monitored. The oldest OTR-300 buoys we have in the field have been talking seven times per day since January of 2011 and are still going strong. The batteries are also providing power to an external temp sensor. If one went only by the power charts, the figures would look much better. Our experience is that power charts are generally inaccurate and they don’t take into consideration the shelf life of batteries.

Originally, we offered OrbComm satellite communication. Our biggest issue with them was that the VHF frequency they use requires a larger antenna than our buoy could comfortably fit. We spent time designing our own antenna which worked well, but there were also issues with the satellite network at that time. Inmarsat offered great coverage over the majority of the oceans to which we were deploying. Inmarsat was less expensive at that point than Iridium, and Iridium did not have the hardware ready for our application.

Since that time, we have purchased the new Iridium modems and have started the process of testing and of becoming a VAR for Iridium. We wanted to provide service to the Chukchi and Beaufort Seas (arctic Alaska) and the Iridium network has great coverage at high latitudes. However, that market did not sufficiently develop so we have stayed with Inmarsat as a well-proven system for our current market.

We would seriously pursue Iridium (or OrbComm) if a customer required it. Messaging costs will vary slightly. Each satellite network has its own strengths and weaknesses.