Airmar M260

[Hooper]

I got my unit yesterday, what is the best way to obtain the proper deadrise angle to cut that box and what tool is best to cut that box?

I read the instructions that show to invert the box and use a carpenter's level to ensure it is level, then mark a line, but space is limited in our boats, I don't see how I will do that trick. My thought is to take ths box, lay a level across the top, press them against the outside of the transom and mark my angle that way.

Same angle right? Just taken outside the boat rather that in the bilge and since I will be placing it just forward of the transom anyway, I think this method would be fine.... what say you all?

As far as a tool goes, I am going to look at this thing and give it some thought right now....

[JohnB]

I have one, they work great.
As for mounting, take a level, across the top, side to side.
Hold it to where it's level, measure the gap. On the other side of it, where your going to cut, draw a line equal to the gap measurement you just did, then draw a line on the sides from that line, to the edge. I cut mine with a jig saw with a med blade. You might want to take a grinder and rough up the surface on the boat, then wipe down with acetone.
I would suggest using GE 2, marine silicone to mount it. Supposedly, they have found that mineral oil softens 5200. If you have to move it, you will be able to unattach it.
Mine has been in 3 years, and has held up find. I put a bead on the bottom, and set it in place, then after it dried, put a bead on the inside and outside. You might want to put some corrosion X on the top "stainless" plate. Every one of those I have seen, rust in about 3 months. For what you pay for it, it sure is a cheap piece of stainless. I used mineral oil in mine, some are using antifreeze. If you have any questions, send me a PM, or you can give me a call. They are great ducers.

[1bayouboy]

Just FYI....In the Patent Doc on this site the deadrise angles are on the three bottom panels are 21 degrees, 13 degress, and 10 degress. I took a pattern off the transom of my '74 Tsunami and measured, and found them to be just those angles.....

[McGillicuddy]

A band saw is what I've always used to cut composite fairing blocks. Should be easy work on a big ol' box. Looks like a great 'ducer design.

I think Big Lew's ultrasound gel is a great idea for bubble free sonar.