Way Overunity device sold in Marine stores ;) Expain this please

[e2matrix]

I'm laughing as I see the specifications in this book for a depth finder or commonly called a fish finder.  But I'm seriously doing a WTF ?  with how they come up with these specs.  This device is of course an ultrasonic transmitter that works at 200 KHz.  I see in the manual it clearly states the output power is 250 Watts RMS and also it states that it is 2000 Watts peak to peak!!!  So I keep thinking with a 12 volt DC input this device must really be drawing some serious current and I'm concerned about how much battery life will be reduced using it without anything to recharge it readily on a boat.  Then I finally come across the specs on the fuse.  One Amp fuse !
   
   So we have a potential maximum input of 12 watts ( or maybe 13.5 or so if the battery is really charged which if it was consuming that much would blow the fuse)  and 250 Watts output RMS or 2000 Watts peak to peak ?  And yes it states Watts - not milliwatts.  Who does Hummingbird think they are fooling?  Are fishermen really that dumb?  Or is this just another fish story in which Hummingbird (the depth finder manufacturer) has taken exaggeration to new levels?   Or is there someting magical about this unit?   Or am I just missing something obvious?  Questions questions Hummingbird.  My bet is Hummingbird is trying to wow some fisherman with claimed huge power levels that are probably a thousand times higher than actual power output. 
  Sumpin's fishy here 
 

[e2matrix]

Just to make sure Hummingbird wasn't just having a bad day when they wrote the manual for that unit I downloaded another manual for one of their current units.  It claims 1000 Watts RMS output or 8000 Watts peak to peak output.  That is with 12 volts input and a 2.5 or 3 Amp fuse so a maximum of about 36 watts input will get you at least 1000 Watts output    

[WilbyInebriated]

it is similar to the way cheap audio amps are rated.
it isn't OU, just shady advertisement.

[e2matrix]

Continuing a little research I find other manufacturers are claiming the same.  Garmin has one that states it uses a maximum 3.5 watts (power usage or input) and is so stated right in the owner manual but it puts out 100 watts RMS or 800 watts peak to peak.  So this is common practice I guess for fish finders.  What is going on here ?

[e2matrix]

it is similar to the way cheap audio amps are rated.
it isn't OU, just shady advertisement.

Yeah that thing with cheap audio amps crossed my mind but these aren't no-name manufacturers.  Garmin is huge, is a big item on the stock market and has a top reputation.  I have a hard time imagining why they would want to risk being caught in such a huge lie about their equipment specs for just one line of things they sell.  I think the bigger part of their business is in GPS units by far.  I still wonder if their isn't some other explanation for this huge discrepancy in power in/power out specs.  I don't think it's OU but I'd like to understand what it is.