Multifunction Instruments and Repeater Instruments

Multifunction Instruments and Repeater Instruments Resources and Information

Multifunction instruments display vital information to help you navigate when out on the water. Repeater instruments extend the range of your data network and combine information to supply you with new data that is relevant to your boat’s navigation. This information includes wind speeds, boat speeds, true wind angles and much more. 

If you’re looking for more marine products, choose from our full selection of boat products and accessories, boating electronics and navigation, or fishfinders, GPS, chartplotters, and multifunction displays.

Multifunction Instruments and Repeater Instruments FAQs

What is a marine repeater instrument? 

A repeater is an instrument on a boat that replicates data transmitted over a data network, such as wind speed, depth, and weather data, to display to the boat operator. Repeaters also combine data to create new helpful data, like wind angle, to assist with navigation. Repeaters cannot operate on their own, as they don’t have transducers; they work in conjunction with other marine instruments to compute data. 

What is a multifunction marine instrument?

Multifunction instruments are the central hub of the boat. These instruments take data measurements and display them on a screen to assist the boat operator with navigation. This data can include speed, depth, wind speed, weather, direction, and more. 

How do I navigate unknown waters? 

While you are clicking around the internet, check out one of the many websites that provide tide information for the area you wish to travel. Also, there are many mobile apps that serve this purpose because while tide information is found on most modern GPS devices, it’s great to know in advance.

Tides have a bigger impact than simply knowing if you will have enough draft to float your boat or enough clearance to sneak under that low bridge. For example, trying to traverse some narrow channels or passes in the midst of a large tidal swing can introduce a host of challenges to mariners who lack the local knowledge of those waters; currents, wave action just to name two that can compound depend on the channel/pass. The same goes for your final approach into a new dock if you were looking to spend the night at your destination.

The web also provides beautiful and detailed satellite images. Often a look at the satellite image of the area you are hoping to explore can yield lots of useful information. Deeper water and sand shoals are easily visible from above, and channels are often marked by boat traffic the day the photo was taken. You can also get a feel for what sort of conveniences are near the marina or dock you had anticipated using. Proximity to grocery, laundry, and restaurant facilities are all important considerations. You can also be well prepared for the layout of the marina’s slips which eases anxiety when trying to line up for docking.

No pre-trip homework would be complete without a look at the weather. Again, electronics help considerably as many boats have the ability to monitor VHF weather transmissions, satellite weather updates, radar, and cellular phone-based weather information. Travel plans on the water often need to be flexible to work around the weather windows. Wind and wave height are obvious considerations, but keeping an eye on the weather can determine how fast you run to a given destination or if spending an extra day at your newly discovered island get-away makes complete sense.

The first aspect of any trip on the water is to do a proper pre-trip inspection of your boat and equipment, but doing the navigation research ahead of time will give you confidence both in your vessel and your plan. A trip to a new destination on the water doesn’t have to mean going far, so start small with bite-sized day trips to endpoints slightly beyond your normal comfort zone. You’ll find an amazing world of waterfront destinations within a day’s run from your home port.

What does a chartplotter do? 

The chartplotter’s job is to show you where you are in the water and to help you navigate to where you are going. That sounds a lot like the GPS in your car, right? Yes and no.

While the chartplotter is run by a GPS similar to what is used within on-land devices, there are additional factors at play on the water, so the functionality and ability to process large volumes of complex data is vital. If the size and structure of the body of water you’re navigating is small and uncomplicated, you can simply type in a destination and a route will be generated for you to follow. However, on larger bodies of water with more complexity, you will likely need to enter waypoints and build a custom route.

Like the GPS in your car, a chartplotter uses GPS or GNSS data to measure bearing, speed, and direction to successfully navigate your route. However, the chartplotter begins to differ from the GPS in your car as you start considering its tracking and route navigation capabilities. A critical element that you must navigate while in the water is the underwater structures that can obstruct your route.

Structures like reefs, sandbanks, wreck sites, and other hazards must be avoided. A chartplotter’s ability to generate detailed electronic charts is another area in which this device differentiates itself from other navigational tools. A marine chartplotter will produce two types of charts: a raster chart, which is basically a scanned version of a paper chart; and a vector chart, which is composed of lines, points, and polygons using information pulled from a database. Vector charts are more dynamic, use less memory, and are more user-friendly than raster charts. In addition to being powerful navigational tools, many of these devices include fish finder functionality that detects sound waves underwater and uses the signals to project an image onto the screen to enable anglers to spot schools of fish in the depths.

How do I select the best chartplotter for my boat?

Offshore boating in the ocean or on the Great Lakes demands a higher functioning chartplotter. As mentioned above, if you primarily boat in small, inland areas, a basic chartplotter will likely serve you well. If your boat offshore, you will need to select a unit with greater processing speeds, the ability to easily download updated charts, and the capability to integrate with other tools and systems within your boat.

Generally speaking, smaller screens work well in smaller boats. Similarly, operators of larger boats will likely need a considerably larger screen since they will probably be situated at a greater distance from the chartplotter given the need to manage multiple interfaces.

Most chartplotters can be bracket mounted, which gives you a lot of flexibility. But be sure that the unit you select can be mounted so that it is visible from appropriate angles and can be protected from water—both waves and weather.

Chartplotters vary tremendously in price, from $150 to thousands of dollars. The type of boating you do and the bodies of water you boat on will determine what kind of chartplotter you need (what you want is another question). If you boat on fairly small inland lakes, a chartplotter robust enough for a transatlantic crossing is simply not necessary. However, if you will be boating on large bodies of water, you will need to spend more to ensure you have an instrument powerful enough to facilitate safe boating and ease of navigation.

Whether you select a fairly inexpensive chartplotter or a very expensive unit with all the bells and whistles, make sure that the unit is easy to operate and understand. The following is a selection of chartplotters that are popular among the PartsVu community. Given the diversity within the PartsVu community—from offshore boaters to fishermen who frequent smaller inland lakes—there is a significant diversity of needs. This range is represented within the units featured.