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+--- Thread: [LW] [LW11] Tide and True Wind Derivation (/showthread.php?tid=9218)
[LW11] Tide and True Wind Derivation - djangotoo - 08-11-19 12:17 AM
My paddle wheel transducer has clearly started slowing up as boat speed is displayed inaccurately. I have subsequently noted that true wind and tide calculations are out as a result. It surely makes sense to use SOG rather than boat speed in these calculations??
Is there any way I can configure it this way?
Axiom/Lighthouse 3
RE: [LW11] Tide and True Wind Derivation - Louise - Raymarine - Moderator - 08-21-19 05:54 AM
Dear djangotoo,
Thank you for your post.
Is the paddle wheel clean and free from debris? What model is the speed transducer? We may be able to replace just the paddle wheel if this is the issue.
There is a reason for using speed through the water and not speed over the ground when making these calculations. Please refer to this FAQ section that will help you understand as to why we use speed through the water.
Many Thanks
Louise
RE: [LW11] Tide and True Wind Derivation - djangotoo - 08-22-19 02:44 AM
(08-21-19 05:54 AM)Louise - Raymarine - Moderator Wrote: Dear djangotoo,Thanks Louise
Thank you for your post.
Is the paddle wheel clean and free from debris? What model is the speed transducer? We may be able to replace just the paddle wheel if this is the issue.
There is a reason for using speed through the water and not speed over the ground when making these calculations. Please refer to this FAQ section that will help you understand as to why we use speed through the water.
Many Thanks
Louise
I am sure that the paddle wheel is fouled to some degree, hence, the degradation in performance, but pulling the transduce inboard is perhaps my least favourite job on a boat!!
In terms of TWS/D, I see the point that is being made at the link but when it comes to deriving the tidal vector (selected in the vessel details pop up) it appears that it too uses log speed. If that is the case, it is surely not correct as tidal streams are a ground based measurement.
I am interested to hear your thoughts
Kind regards
RE: [LW11] Tide and True Wind Derivation - Louise - Raymarine - Moderator - 08-22-19 03:40 AM
Dear djangotoo,
Tidal vectors are a more complex calculation and the data derived to display these local tidal vectors are from COG, SOG, heading, STW and magnetic variation.
Many Thanks
Louise