• As a source of basic information on all sorts of equipment, in a very concise form, we think the West Marine Advisors, both in their catalog and on their website, can't be beat. They don't push any particular products - they cover the basic technology and identify the important features to look for on a number of topics.
  
  
• For actual product tests and comparisons, we found, once again, that  Powerboat Reports  was the most useful of the various periodicals. Objective "real world" tests, fair market pricing comparisons, and technically accurate data. You can search their website for past articles, and purchase electronic reprints on-line.
  
  
• Our "Useful Websites" list also has some of the Internet forums that we found to have knowledgable people willing to share their experience. It pays to "lurk" for a while before posting a question, if for no other reason than to get a feel for whose answers are going to be unbiased and based on objective experience, rather than opinion and hearsay.

The JIS-7 standard calls for a device to be operable after being submerged to a depth of 1 meter, for 30 minutes, while the CFR 46, Subpart 110.20 standard calls for the device to withstand a 65 gallon per minute stream of water from a one inch nozzle, from all directions, for five minutes, without leaking. 

These certifications are reasonable indicators of water resistance, but are not guarantees of waterproofness. Keep in mind that you may wind up accidentally exposing your devices to water for much longer periods of time when water conditions are bad, or it's raining, or even if you get careless washing the boat .

For example, suppose you install a piece of electronics so that moisture can collect behind knobs, on connectors, or on case seams. A bad-weather day on the water, or a little agressive hose action at the end of the day, and you could still wind up with some problems, as the water sits collected against a seal for hours or even days.

We actually had this happen to our VHF radio. It is JIS-7 certified, so we naively thought we could hose it off at the end of the day (as part of the boat cleaning process), and let it drip dry. After the third or fourth trip, the squelch knob was frozen. We returned the radio and got a replacement, assuming the radio was defective. When the squelch knob started getting sticky on the second radio, we finally realized what was happening. We hit it with some Corrosion Block® to free things up, and now make sure we have a cloth covering the radio when washing down the boat.

This is especially true for things that have a fairly complex user interface. No amount of written text or even video can adequately describe how some things work. For example, I was never a big fan of real-time sonar displays until I started using the A-scope feature on our Furuno LS-6100. Now I keep A-scope on all the time, and would not buy a sonar without this feature.

So if possible, see if you can find someone with the same equipment and give it a try on the water. Go to stores that have live units on display, and try running the simulator programs. You won't be sorry!

• Download a user manual for the device from the manufacturer's website
  
  
• Read the manual. Write down one questions about the item
  
  
• Call the manufactuer's tech support line, and ask your question. Explain that you are considering buying the item, and just have this one question...Then gauge their response, especially their attitude..

BUT - don't forget that another major irritation is the time it will take to have the item repaired or replaced . Some manufacturers prefer to simply replace a defective unit, rather than try to fix it. Others will fix it, but you have to return it to the factory. Still others have repair depots or partners that you have to send the broken unit to.

Which approach is best for you? There is no stock answer. We think it depends on your personal situation (location of the repair depot or manufacturer, your level of patience). But don't assume that a local repair depot will be faster than mailing it to the manufacturer. Sometimes the repair depot will not have the parts, or will be so backed up with work that it will take weeks to get your item fixed. 

Bottom line: if you are trying to decide between two or three items and can't make a choice based on technical features, check out the manufacturer's Tech Support line, and their repair policies. That may make the difference!