Lowrance HDS-5m doesn't interfere with compass. Much.

[MarkSF]

I just installed a Lowrance HDS-5m chartplotter above and forward of the compass. I was somewhat alarmed to see that the chartplotter has a magnetic latch on the map chip compartment, initially.

Anyway I tried moving it around near the compass and when it is above it and 6" forward, like it is now, the largest deviation I could cause was about 1 degree.

To the sides of the compass, however, I could cause 5-6 degrees. So be careful of the orientation.

[svHyLyte]

Unfortunately, the effect of the magnetic lock will very depending upon the heading of the yacht with east/west components most strongly effected. Since you've already installed the device, you might want to make up a deviation table by finding a place where you can swing the boat. We found the magnetic latches on the newer Garmin devices introduced a major error within 3 feet of our Compass. Some simply removed the magnet and taped the door closed. We purchased one of the last non-magnetic units (3205) very inexpensively but of course it's "discontinued" and so will only be supported for a few more years.

[MarkSF]

Thanks, I'll try it next time we go out!