Paddle Wheel Speedometer

[Cmdr311]

I recently bought a 1967 Pearson Commander which has a curious looking bracket mounted in front of the paddle wheel speedometer. Sort of resembles a raked tuning fork. I think the purpose is to keep seaweed from fouling the paddle wheel. Has anyone ever seen one of these before? My concern is that it could be a seaweed catcher and cause more problems than it solves. I'm thinking about removing it, but seeking comments first.

[mad_machine]

there any reason to keep the speedometre in this day and age of GPS?

[SolSailor]

GPS will give SOG, but will not take into account currents and other factors that may affect speed through the water.

[Cmdr311]

You raise a good point... My android phone & ipad probably give better readings anyway, but, you know, nostalgia. Since its there and it works guess I just want to keep the wheel turning.

[SchockT]

Originally Posted by mad_machine

there any reason to keep the speedometre in this day and age of GPS?

Speed over water is different from speed over ground. If you sail in areas where there are a lot of currents it is useful to have both pieces of information so you know how much current you have with or against you. In our waters being aware of such things can get you to your destination faster.

As for the "tuning fork" I have never seen the like! Maybe it is supposed to align the flow with the knotmeter transducer?

[Cmdr311]

Yeah, I've wondered if it might function like a vortex generator on an airplane wing to align the flow of water over the paddle wheel?? Nobody in my boat yard has seen anything like it before. I'm about to paint the bottom and am considering taking it off.

[Faster]

Originally Posted by mad_machine

there any reason to keep the speedometre in this day and age of GPS?

SOG is not particularly helpful when you're trying to trim sails for best speed through the water... For the full picture you need both..

That an odd placement for a paddlewheel.. do you notice a big difference in indicated speed from one tack to another?... btw I'd probably pull that 'bracket/diverter/tuningfork/whateveritis...'

[Sabreman]

there any reason to keep the speedometre in this day and age of GPS?

As other posters say, Speed over water is very different than SOG and useful to know. What many people don't realize is that the GPS speed is an average over a longer period of time and not an instantaneous velocity. Thus, you could be slowing and not know it for a minute or two. SOW is an important piece of information when determining the effect of sail trim.

Example - last summer, we eased the traveler 2" and saw an immediate 0.5 kt increase in boat speed. With a GPS, the effect would have been averaged out and difficult to determine when factored with other variables.

I don't look at GPS speed when determining performance.

[Cmdr311]

Agree on the odd placement. I only sailed it a few times in the fall before we hauled her for the winter. I didn't notice any speed differences from one tack to another. My first reaction when we hauled her was, "What the...?" I think I'll take it off unless someone who knows its benefits pipes up. I can always put it back on next year if the speedo fouls excessively.

[outbound]

Agree with S man need both to figure out set and performance in real time . If growth,weeds etc. are a concern can use ultrasound speedo Airmar cs4500. airmar part# 44-063-1-03 or Raymarine part # 44-063-1-03. Never fouls. No maintenance. Never have to pull it out to clear and hope you get the plug in before your boat sinks. Cool piece of kit but dear.