gregy - anchor alarm plugin@Scott Bender ju...
anchor alarm plugin
@Scott Bender
just wanted to check some of my own logic,
i noticed when re-reading plugin description, that it will set initial radius to D x 5.
q: did this change at some time over past year? (maybe more)
i recall it initially was a fixed ammount, so
i built some nodered logic to set initial radius when i “auto drop” ..
but thinking now i can remove it from my flow.
q: i assume it does the calc & sets radius at the point of calling the “drop anchor”
(good.. as this will stop it alarming whilst i set anchor)
🙂 i cant test, as im currently at anchor with alarm set!
Q; D is obviously depth below surface …. I assume anchor bow roller height is not used in calc?
37 Replies
That’s when setManualAnchor is called. It does use bow roller height
That should be used after you have already anchored
ok now im confused .. normal
it uses bow roller height, but only when calling setManualAnchor?
when using dropnchor - what does it do? (for alarm radius)
dropanchor does not set the radius
It simply marks the anchor position
ah! thats why i built logic into my flow .. its all coming back now
Once you let the rode out, call setRadius
Then it sets the alarm radius based on your distance from the anchor position saved when you dropAnchor
In WolhelmSK, you can hit the anchor button at the top when you drop it. It will turn yellow.
understand, however i have an “auto drop” nodered flow..
i auto call drop anchor - when chain is going out AND its length exceeds DepthBS
i then back up etc…
i set an alarm radius at deop, so that alarm doesnt go off whilst anchoring.
Once you’re done letting the rode out, hit again. It will turn green.
yep understand… but i recall kept getting an alarm … and this was to overcome it
The alarm won’t go off after calling dropanchor. Not until you setRadius
ah ok… i must have messed something up …
Maybe there was a bug at one point… I don’t think so.
…. ok, but fairly certain i used to (2 yr ago) get an alarm whilst setting… i know i went down the path for some reason 🙂 maybe it was something else..
.. anyway i will keep my flow… seems to work .
but im going to update flow to include bow roller height in my calc when i set initial radius… (my bow roller heigh vs shallow water … messes with the x5 calc!)
Why not just call setRadius (with no radius parameter) when you’re done?
how does this calc alarm radius?
It uses gps position, it knows where the anchor is, so it just computes your distance from there.
So no need to take rode length, etc. into consideration
(when you drop anchor, it does use boat length, heading, gps location on the boat to compute the anchor position when you dropAnchor)
ah ok… understand, this is “after” finishing anchoring etc.
but its then dependant on boat distance from anchor when the command is given … ?
which could be at full stretch.. or not.. so results in diff calc?
Yes, true. I always do it right after I back down in the anchor. (And I only have 30 ft of chain)
I didn’t consider where your don’t normally get a full stretch when done…
i backdown on anchor when im at the bow setting anchor, snubber etc
(wireless remote for thrusters and engines 🙂
.. so i’m not near a screen that i can easily execute the command in wsk when backing down etc ..
30ft of chain ? but non chain rode also i assume 🙂
Yes!
Ok, so I need a hybrid of auto/manual.
🙂 80m of all chain.
welcome to northe east coast of aust.. where we get 6+m tides!
Yikes!
… which is why im kinda fixated on getting anchoring right!
… and 3kts of tidal flow is not unusual
Definitely not that bad here. It’s the weather that gets me…
So I am going to add a setRodeLength to call after dropAnchor
Which is basically what you are doing I think.
haha.
today is last day of “winter” in Oz.
it will hit 30C (86F) here today …
a thought,
when calling dropAnchor.
what about it setting an initial alarm radius that is
(depthBS + bow roller) * 5 .
… then it will be overwritten by any of the other commands .. so would still work as you describe..
Why?
That’s pretty arbitrary
I guess if you forget to call setRadius?
so there is an intial alarm radius set ..if you forget to do other commands
Actually, I should send an alarm if setRadius is not called after some time
that would also be useful.
the *5 is arbitrary i agree .. some put out less, others more.
its my usual logic and starting point.
i fine tune my alarm radius later on also
Same. Once I have a decent track.
It’s never perfect.
yep.
ok … you have answered a bunch of questions about how it works - thx
i can now refine my logic.
have a great day
I added a few issues to the plugin to cover this discussion.
will have a look…
Please comment if you have anything to add.
yep
hmm… auto adjust the alarm radius based on depth changes?
interesting thought, but i think that might end up confusing people…
trying to wrap my mind around the logic…
eg the original radius based on depth at anchor drop location,
so you use the change in depth (at boat position at a given time)
to modulate the original alarm radius..
however consider… with a big swing radius, and swinging onto a lee shore… the depth under boat would reduce,
but this would have nothing to do with a tide change …. only be relates to deoth at boat position at a point in time..
.. nit sure if this is what you would want ..
Yeah, that was a terrible idea! 🤣