I'm new to Reefmaster and will be buying a sonar unit to work with the reefmaster software.

The unit will be attached to a 8' inflatable dinghy. I'll be mapping near shore areas (100' or less) primarily looking to make an accurate survey of depths and obstructions/underwater hazards. A small screen is fine since the purpose is just to collect data and transfer it to a computer to make a map.

Any suggestions on the best sonar unit, or suggestions on where to kick off researching?

Will depend on how much you want to spend and if you want side scan (structure scan)... If it's just basic depths you could go for something like the lowrance elite units. Side scan will be more expensive - one of the hds type units. I started with an elite 7, loved it, but then wished I had Side scan so bought an hds.

I don't have experience with the garmin or other units, but I have been happy with lowrance. Have a look on eBay, there are sometimes some good 2nd hand units. Lowrance.com will be the best place to look at specs / prices.

Just my opinion, I'm sure others will prefer different units, but I loved the elite unit and now think the hds 2 is ace :-)

It also depends a little on what you plan to do with your finished maps. If you want to display them on your unit, then you should go with Lowrance (or Simrad), as they provide a free tool (the Insight Map Creator) that ReefMaster makes use of to produce great looking, full colour maps that you can use on your device.
Sidescan is also very useful, and the newer Elite Ti units from Lowrance are a really nice new range that can include sidescan (with optional TotalScan transducer) for a very reasonable price. One thing to be aware of is that units with small screens log sonar just as well as the bigger units, so there is no need to spend money here unless you really need a big screen on the water. Humminbird also do some nice smaller SS units. To make full use of the sonar viewer and sidescan mosaic features within ReefMaster, you are currently limited to Lowrance, Simrad or Humminbird units.

I am another new user and have been considering the Elite-5 Ti but I get a little lost when it comes to transducers and the need for external GPS. Any suggestions for mapping the hard bottom and any discernible sediment? The intention is to use the bathy data exported to CAD software for integration with topographic surveys. Thanks for any help!

The Elite 5-Ti is a self-contained unit with everything you need to create maps in RM - no need for an external GPS. I have an Elite 7-Ti mounted on my kayak and it is a great unit for the money - in fact I would say that the new Elite Ti range are amongst the best value units around now.

Hey Matt, if I recall correctly, the Elite Ti series don't include a digital compass, right? Is there any compasses that I could use with the Elite TI and RM?

There are no units out there with a buildt-in compass. Look to Point-1 to get compass-heading to Elite 7 Ti or any unit with NMEA2000.. (Elite 5 Ti does not have NMEA2000 and therefore does not support Point-1.)

Another option is to find a digital compass that outputs NMEA 0183. Don't know about the Elite 5 but the Elite 7ti will accept NMEA 0183 "HDG" sentences, as will Reef Master, so they should work together.

Another new user here. I am interested in the Elite 5 ti for creating a bathymetric map of shallow lakes (max 15m depth). I'm hoping for a unit that can collect depth and coordinate automatically while we drive the boat, say every 1-5 seconds for example.

I wish to create my maps using ArcGIS, and my understanding is that Reefmaster will allow me to extract the needed data into files I can import elsewhere.

Does the Elite 5-Ti allow for automatic logging of location and depth? Is this function and data exporting hard to set up? I don't necessarily require a unit with large screen like the more expensive models have, but will these models provide more accurate data? (we only need the data collection functions)

As much as I'd love you to buy ReefMaster, it is probably overkill for the task you propose. You can record depth and position data automatically on an Elite 5 Ti at a high rate, and store this data to a memory card. You can then use the free Insight Map Creator application from Navico to extract depth and position data from your recorded sonar logs to a CSV file, which you can use as a data source for ArcGIS.

Awesome response, thanks so much. Frankly, I'd be happy buying Reefmaster just for all the support available! (Especially since this is a student grant and not my own money).

It looks like the Elite 5 ti is well suited for my needs. I will look into the Navico software, though Reefmaster does have some interesting tools that might be useful for my project, specifically the Sonar Viewer. My project is investigating sediment distribution in a small reservoir, so looking through the sonar images may help determine whats raw sediment and whats not.

Another follow up question:

Do the other Lowrance models (like Hook 4) process/collect/etc data as well as the Elite 5 ti? I assume that the newer the model, the better the technology, but considering I don't actually need the map functions (only data collection), it seems other units would work tool. It looks like the Elite TI series and the Hook series can both log sonar data; is anyone familiar with the differences between units with respect to sonar and GPS accuracy/etc?