Originally Posted by Don1500
maybe, if you have this it just might give you more warning than the thud of the box hitting your hull
Not according to all the reports I recall
reading by cruisers that have them and the math confirms it. Just go back to post #11 by Roy who has one and seems to like it. Remember these units do not look straight ahead but at a down angle. Roy reports 100' range in 20' of water under ideal conditions in a harbor. A shipping
container is 8' high. Maybe one end sits lower in the water so it's 10' down. That would give a maximum range of detection of 50' under ideal conditions in quiet water in a harbor.
At 6 kts you would cover that distance in 5 seconds. I assume you use an autopilot
or some sort of self steering
on a long passage
. I believe the great majority of sailors on passage
do. I see 0% chance of getting to the helm
and altering course in 5 seconds if the AP is driving. Even if you don't have any sort of self steering
and have both hands on the wheel
, do you think after a few days at sea, standing at the helm
you hear an alarm
sound, look for the source, figure out what it is and decide to go hard to port or starboard to miss the container in max 5 seconds?
Also, I have read that they can give false alarms from wave turbulence when the seas pick up which would mean you would be doing frequent 180s on every passage since 5 seconds would not leave you enough time to decide if the alarm
you hear is real or false.
I think a forward sonar would be a great tool to use like Jim Cate describes and if I had a couple of unused boat bucks around I would add one. For now I'll have to make do with what I've got.