Well, actually of 4 fans--but that story will develope. We have used the Hella small fans for over 20 years. These are about 6", are single speed, will fold flat against an overhead etc. They use about 270 milliamps of power, and are "sort of" adequate when its really hot. (Cost about $22)
We have also used the larger Hella fans, which are two speeds, about 7" do not fold flat, and use about 200 milli amps--they are twice the cost of the slighty smaller single speed fans. I have put in 4 of the single speed in the Tom Cat 255--one on each side of the windshield and two over the head of the bunk. I also put in one of the two speed over the stove--both for air distribution when using the Wallas as a heater, and also for odor/heat dissipation when cooking. Cost about $70)
We had used the 12" "Endlass Breeze" by Fantastic Van fans for years in our RV's--they are great--and now come in a boat model--two legs rotate out and they are three speed. We have used one in the hatch of the C Dory 22 to move air when it was hot. I put an ampmeter on ours and got the following readings: setting 1=1.27 amps (about 5x the small fans), setting 2=1.93 amps, and setting 3= 2.90 amps. So, although this is a great fan, it is pretty power hungry. Fan Cost: $90
At the "concerts in the park" we had noticed people with 8 "D" battery run fans--they claimed 24 hours of use on one set of batteries--sounded pretty good. We found one of these at Walmart--it was about $12. It is 10" diameter and called "O 2 cool" What the heck--bought one. I had been using it to move cool air into the bunk area on the Tom Cat 255 (air conditioner on the roof) while I was working on the back of the electrical pannel. It seemed to be working fairly well.
So...I put the ampmeter on it: at low speed it was using 0.46 amps (about twice the small fan, and less than half of the big fan) On high this fan used 0.66 amps (about 3x the amount of the small fan and half of the 12" fan.
Summary--best buy for cost and power usage, with a moderate amount of air moved is the "O 2 Cool". We will have to see what the durability is, but for $12, you can buy one a year and be ahead!
We have also used the larger Hella fans, which are two speeds, about 7" do not fold flat, and use about 200 milli amps--they are twice the cost of the slighty smaller single speed fans. I have put in 4 of the single speed in the Tom Cat 255--one on each side of the windshield and two over the head of the bunk. I also put in one of the two speed over the stove--both for air distribution when using the Wallas as a heater, and also for odor/heat dissipation when cooking. Cost about $70)
We had used the 12" "Endlass Breeze" by Fantastic Van fans for years in our RV's--they are great--and now come in a boat model--two legs rotate out and they are three speed. We have used one in the hatch of the C Dory 22 to move air when it was hot. I put an ampmeter on ours and got the following readings: setting 1=1.27 amps (about 5x the small fans), setting 2=1.93 amps, and setting 3= 2.90 amps. So, although this is a great fan, it is pretty power hungry. Fan Cost: $90
At the "concerts in the park" we had noticed people with 8 "D" battery run fans--they claimed 24 hours of use on one set of batteries--sounded pretty good. We found one of these at Walmart--it was about $12. It is 10" diameter and called "O 2 cool" What the heck--bought one. I had been using it to move cool air into the bunk area on the Tom Cat 255 (air conditioner on the roof) while I was working on the back of the electrical pannel. It seemed to be working fairly well.
So...I put the ampmeter on it: at low speed it was using 0.46 amps (about twice the small fan, and less than half of the big fan) On high this fan used 0.66 amps (about 3x the amount of the small fan and half of the 12" fan.
Summary--best buy for cost and power usage, with a moderate amount of air moved is the "O 2 Cool". We will have to see what the durability is, but for $12, you can buy one a year and be ahead!