Firstly, because we can measure it. Until recently, GPS has been used to calculate a ship’s speed through water, with the vessel speed log taking somewhat of a back seat. However, local ocean currents determine the difference between a vessel’s speed over ground and its speed through water. This part of the equation has been missing, until now.

When it comes to vessel performance and behaviour – including vessel fuel consumption – speed through water is a key factor. In fact, it’s rather critical. Changes in the resistance a vessel experiences in transit (due to ocean surface currents) impact the vessel’s speed through water. As a result, accurate measurements of true speed through water are becoming increasingly important as input for vessel fuel optimisation and hull performance estimation.

Speed through water is a hard parameter to measure. Dry, sensor-based solutions – such as ours here at Miros – haven’t been accurate enough in the past. Measuring speed through water with GPS and acoustic speed logs – below the surface of the water – is the standard. This approach, however, often comes with various challenges related to systematic errors and data being influenced by noise (due to air bubbles, turbulence, inadequate calibration etc.). There are high installation and maintenance costs associated with submerged instrumentation too.

Miros Speed Through Water is significantly more accurate than traditional speed logs, measuring with a variance of 5cm/s, whereas speed log variances can range from 10cm/s to several m/s.

Fuel costs are always the biggest expense in operating a ship, in fact, they make up 50-60% of the operating costs. Accurate data on a vessel’s speed through water allows shipowners and operators to optimise vessel performance by appropriately scheduling hull cleaning and avoiding operation at sub-optimal speeds. Accurate speed through water data is an important tool for controlling and optimising vessel fuel consumption, as well as lowering emissions, which will be particularly important when the IMO’s 2020 sulphur cap comes into force. This data is also valuable in vessel chartering when handling weather claims.

Any vessel where it is important to optimise fuel consumption and maintenance intervals (hull cleaning, for example). Additionally, beyond the bottom line, companies that care about their carbon footprint (or have customers that do) stand to make gains too. Efficiency is about more than just cash flow.

Future-facing operators, both onboard and onshore, will use this data in a variety of ways. Onshore, decisions will likely involve weather claims and hull cleaning regimen. Onboard, the data provided by Miros Speed Through Water can be fed into decision-making software on the bridge, aiding crews operate at optimal speeds.

A virtual sensor is a system which uses information available from other measurements and parameters to estimate a quantity of interest. In the Wavex system, we use information available from radar, GPS, and gyro to estimate wave spectra, wave parameters, surface currents, and STW. This makes a practical and economical alternative to perform physical in-situ measurements.

We estimate commissioning to be just a couple of days. In cases where the hardware is already in place, things move a lot faster. Additionally, the more up-to-date the hardware, the less tuning is required.

X-band radars do require some maintenance. As the Vessels have many radars it should fit right into their schedule.

Well, the data can either be stored locally on a computer, or it can be accessed easily using our Cloud solution.

Speed logs are obligatory on all vessels. Their shortfalls and the challenges associated with them don’t matter, nor the fact that they are often simply neglected. If you have one, you’re compliant. As the importance of accurate speed through water data, and its ability to drive efficiencies in vessel fuel consumption, hull performance and beyond, become clearer to the community, we certainly won’t rule this out!