calculating wiper arm and blade lengths?

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Apr 11, 2008
Vessel Name
Vessel Make
DeFever 48
Our new to us boat has the motors but no arms or blades. How do you figure the lengths for articulating arms and blades?
Daddyo wrote:
Our new to us boat has the motors but no arms or blades. How do you figure the lengths for articulating arms and blades?
*It's been I while since I went through this, but this is my recollection:

Using existing motors, my first thought to install articulated arms/blades*was to consider*the desired swept area of the glass when viewed from the pilothouse.* The number was 11".

I then installed*articulated arms with 11" blades, and the motors could barely move them with dry glass, just a little faster with wet glass.* Used them a couple of months, and even tried RainX to lubricate, but it soon wore off.* Downsized to 8" blades which worked for a couple of years.

Then, rewired the boat which included an analysis on wire size needed to supply 12VDC power to the (3) wiper motors.* It became very obvious that the #16 wire with a 45' round trip was not adequate for the amperage demand, and the circuit was rewired with a #8 supply wire.

Have reinstalled the 11" blades, and everything works good.
Only thing I could think of is maybe find a long straw or something and tape it to where the arm is supposed to attach and turn it on and try and mark the limits of the swing to left and right and get an approximate length and then pick up the parts @ an auto parts store?
Only other idea I had was maybe trailer her to the jiffy lube- they always seem to want to add a filter and new wiper blades to my bill when I go there in my truck! :)
The place to start is your eye height when looking thru the glass.

Standing , sitting , for you and the bride.Mark the spot looking at the horizon and measure.

That will give the location you need swept.

The parallel arm units will allow the blade to be verticle and allow a wider sweep.

Multiple speeds is nice , and the better units will come with a parking feature.

The controls should be really EZ to reach sitting or standing as the unit will be turned off and on frequently in a light rain .

A cheap auto store FW washer should be installed as salt will destroy glass very quickly.

NEVER use wipers on plastic.

The marine units from IMTRA are sold at Defender , and IMTRA has a great web site to figure it all out.

Marine units are required if the boat will see salt water.
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