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Garmin 451s chart plotter

A great combined fish finder and chart plotter, at a reasonable price.

A great combined fish finder and chart plotter, at a reasonable price
I got this unit around 3 years ago and have used it extensively ever since.  It's quite a chunky box, with a four inch screen. Round the back of the unit are three sockets, you'll be using the one for power and transducer signal, but I very much doubt anyone on a kayak will use either the NMEA socket or add an external GPS antenna.  The 's' designation after the 451 tells you you've got the sounder version. Mine came complete with a dual frequency transom mount transducer and power cable.
From a kayaker's  point of view the transducer cable is a good one, as it breaks in the middle with a waterproof plug and socket, which is relatively slim line and certainly means you can fit the whole thing with just a 20mm hole though the deck. The standard transducer unit doesn't fit the scupper holes on Ocean Kayak kayaks, but there is a slim line one that can be cut down a bit to fit. I use my 451s on my Tarpon 120, my 140 and my Scupper Pro, and for each of those kayaks I use an in hull installation, with the transducer Sikafexed to the inside of the hull. When you come to wire the unit up you've got a quite daunting bundle of cables, but all you are going to need is the red and black battery connectors, with mine I cut the rest right back to the insulation, and then shrink wrapped the whole bundle, to prevent any water getting into the wiring loom. The unit can do amazing things with the extra wires, like making DSC radio calls when linked to a suitably equipped radio, but I'm afraid this kind of stuff is only really for use on boats and is pretty pointless on a kayak.
The first time you power up, the unit seems to take an age to acquire its position, around 30 seconds or more in fact, but after its got its initial fix, it comes on almost instantly. I used the unit for a couple of years with just the basic mapping, and have to say, it's pretty hard to justify the money for the upgrade to g2 Vision mapping, as the basic set of maps are very detailed, and a lot of the functionality provided by the g2 upgrade isn't really that much use on a kayak being aimed more at powered craft.
If you do want to upgrade the mapping the Garmin has an SD Card slot on the front panel, protected by a waterproof hatch and seal, and this arrangement  works well. You can save data from your computer to an SD card and transfer the data to the 451s and vica versa, which is useful for those who like to plan their trips from a computer.
In use the Garmin looks like it's got seven buttons and a cursor pad, but on closer inspection, it really just has an on/off button, a cursor pad, and three rocker switches, which are divided to look like 6 discreet buttons. Getting around is pretty obvious, and after a few trips I got the hang of navigating all the most used features. The cooler stuff, such as tide times and tidal flows, is easy to get at, just look for a data point, put the cursor on top, and press select, its then just a matter of choosing the data you want. A home key is included, and this will always take you back to the top menu level no matter how far you've rummaged into the menus. Zooming in and out is also easy, with dedicated zoom keys above the cursor pad. Various displays are available, including a split screen view with both charts and sonar data, but as the screen is a little on the small side, it's quite difficult to really understand the sonar data in this mode. The keys are a decent size, and, at a push, it's possible to operate the unit when wearing gloves in the winter. I've included some screen grabs in this review, and these show tide times, and tidal streams, the later can be shown as either a table or a chart, both really very useful for kayak anglers.
The 451s is equipped with an SD card slot, the front panel, protected by a waterproof hatch and seal. This arrangement  works well. and not only enables you to upgrade the charting to Garmin g2 Vision charts, but also enables you to take screen shots of the screen off the unit, or transfer your own marks and way points to and from a computer, using Garmin's  Homeport software.
After around 6 months of use, I started to notice that both the plug and sockets used to connect the unit to the power supply were starting to go green, with corrosion. This was cured with a quick spray of ACF-50, and I've given it a squirt every couple of months ever since. Another area that caused the unit to fail to operate was the fuse holder, which suffered from the same greening inside the holder, I cleaned it out with wire wool, and sprayed with ACF-50, and again, haven't had any further problems. 
Current wise, the unit runs for a whole session on a 7Ah battery, and will even run to a couple of sessions if used sparingly.
The mapping that comes with the unit is very good, and contains loads of detail, it enables you to position your kayak over even relatively small holes and banks, the speed display is also useful. The fish finder side of the unit is, as you would expect from Garmin, pretty good as well, and doesn't seem to suffer from being in the same unit as the chart plotter. My unit uses a twin frequency transducer, 50 and 200kHz, giving you the best of both worlds in both deep and shallow water. In use you can get a pretty good idea of the composition of the bottom because of the easy to see colour screen. The unit is excellent for finding fish holding structure on the bottom, but I'd treat some of the 'fish' returns with a pinch of salt. Use the unit to find places where fish are likely to hang out, rather than thinking it's going to show you individual fish, although it can come in handy for locating shoals of mackerel/herring which show up very clearly.
Overall I've been very impressed with the 452s, for the price, it offers excellent value for money, with good quality base maps, and more features than you are likely to use in a lifetime of kayak fishing.

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Discover Kayak Fishing
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