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Knot wheel replacment

Greetings all I am a new member and have found this site to be awesome
I purchased my E29 Brillin Leannan in 2017 without knowing how to sail or really anything about sail boats after a good going over the boat I felt confident with the state of her and my ability to repair the systems that were in need of a little Luv I have since thought myself to single hand her in the SF bay ( home marina was on Alameda) so that being said trial and error are swift at showing you when you make an error any way on Jan 21st she was dropped off in Tacoma for bottom pained zincs and some mast work and and discovered a blade on my prop is broken all the way yet is still attached ?? I was able to find one through this group
(yea team ) my next question is how to replace the knot wheel and where would the knot meter have been?
 

goldenstate

Sustaining Member
Blogs Author
What's a knot wheel?

Do you mean a paddlewheel transducer in your hull to measure boatspeed?

I think the money-saving advice is to ignore it and look at GPS speed on your phone if you care.
 
What's a knot wheel?

Do you mean a paddlewheel transducer in your hull to measure boatspeed?

I think the money-saving advice is to ignore it and look at GPS speed on your phone if you care.
Yes that's it and I curently have no instruments so I am trying come out of the dark ages I just repaired the depth sounder
 

steven

Sustaining Member
As an alternative or supplement to gps speed devices there is a thing you can buy for a few bucks called a Knotstick. It is a calibrated tube connected to a drag disk by an elastic line. You throw the line/disk over the side and it read your speed from the tube. Totally mechanical. I have been using one for years decades even though I have a working paddlewheel and instrument (Raymarine ST60).

Note also that only way to keep the paddlewheel free of marine growth (so it will turn smoothly) is to pull it and replace it with a screw down plug when the boat is in its slip. Then you pull the plug and put in the paddlewheel before getting underway. For the few seconds that you are switching the plug in and out there is an open hole in the bottom of the boat and seawater squirting into your eye.

--Steve
 
That sounds like a lot of trouble I typically dive my boat about about 2 times a year when it was in Cali I'm hoping to be able to do it more often now that it's finally in the PNW
 

goldenstate

Sustaining Member
Blogs Author
As soon a money allows I have a laundry list of items that are begging for cash
Navionics is $15 per year. Much cheaper than whatever paddlewheel transducer your might replace per your original post, and you get excellent, constantly updated chartplotter software too.

Add one of these to your pedestal guard ($10 from Amazon)


and you get the best bang-for-your-buck information-system improvement possible.

$.02,

Tom
 

goldenstate

Sustaining Member
Blogs Author
Navionics is $15 per year. Much cheaper than whatever paddlewheel transducer your might replace per your original post, and you get excellent, constantly updated chartplotter software too.

Add one of these to your pedestal guard ($10 from Amazon)


and you get the best bang-for-your-buck information-system improvement possible.

$.02,

Tom
There are also a number of free speedometer apps in the Apple and Android app stores.
 

JPS27

Member III
I took my paddle wheel out and replaced it with the piece whose end lays flush to hull. the wheel gets gummed up constantly, so a pain. I don't miss it. Just look at my chart plotter or phone for speed over ground.
 

steven

Sustaining Member
I mostly keep mine out for the same reason. Don't find much use for it in any case. Can pretty much see how fast I am going by looking at my wake.

Tom, thanks for the tip on the iphone holder. I put it on my list for when I eventually get a pedestal guard.
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
Paddlewheel speed is useful for racing, testing sail combos, wind angles, polar stuff. From what I'm told It registers speed change instantly, whereas GPS reads from samples. (Although my GPS speed does go up when surfing down a wave).

Seems to me most paddlewheels were installed on boats before GPS got cheap, much like the fathometer sticking through the hull next to them. I don't miss either.
 

steven

Sustaining Member
You also have to calibrate the paddlewheel. Traditional way to do this is find a marked mile and traverse in both directions, at a fixed speed as shown by the knotmeter, and timed with a stopwatch. Then calculate the speed of your timed run and compare to your instrument speed to get the correction factor.

By the way, note that the paddelwheel shows speed through the water while the gps shows speed over ground.
 

toddster

Curator of Broken Parts
Blogs Author
Indeed. The difference between gps speed and paddlewheel speed gives you some idea of current speed. Something that can be of significance in the PNW. FWIW, the scanmar speed transducer also gives you water temperature. Depth is more vital. Crazy people who like to jump off their boat and scuba dive in cold water might even get some benefit from sonar/fishfinder, to help find interesting dive sites.

All of the above aside, the preferred location for transducers is at the flattest possible part of the hull (pointing straight down) and away from the keel. Pretty tough to do on a small sailboat. The previous owners of my E29 had a depth transducer epoxied to the hull in the bilge, just forward of the engine. Maybe a bit too close to the keel? Anyway, it was dead and abandoned in place.

On the E29 Mk I design, there is a hatch opening into a small separate bilge in the bottom of the hanging locker, just forward of the mast. On the Mk II design, I think this is the middle of the passageway, so IDK if there is something analogous in the head area? Maybe a shower grating? Anyway, I found this little bilge to be a convenient place for transducers. Especially since the wiring from the mast-mounted stuff comes through the hanging locker anyway and it can all bundle together on its way to the cockpit. When you pull the paddlewheel (there are clamshell shutters in the housing that are supposed to swing shut and minimize water ingress - sometimes they work) and swap in the blank plug, all the water gets contained in that little bilge where you can bail or sponge it out. At worst it's about a gallon, usually much less, unless you really fumble something.

Later... being one of those aforementioned crazy people, and a toy junkie, I eventually installed a sonar/fishfinder that works with the chartplotter that I eventually upgraded to. This needs to be vertical (when the boat is level) and comes with a little fairing block that you cut to match your hull, though it still has to be pretty flat to start with. The downside is that it makes a little curved blister in the hull that can't be good for racing speed. (could have sworn I took a picture of it, but can't find it.) Anyway, I installed this up near the bow, in the forward-most locker under the V-berth, just forward of the crash bulkhead. It's barely flat enough. One reason for this may be specious, but for years I kept the boat in a shallow marina, with a very long, shallow, poorly marked, unlit and foggy approach through a swamp. At times one had to feel the way through this at a painfully slow crawl. With a few inevitable bumps into mudbanks. I used to kid myself that my reflexes were fast enough that if only the transducer were out at the front of the boat, instead of the middle, I'd be able to steer or back away before the keel hit the mud. So now it is. (And there are other shallow anchorages and passages in the area like that.) However, on sporty days, when beating into the chop, that transducer comes completely clear of the water sometimes, and it confuses the chartplotter. *sigh* Nothing's perfect.
 

steven

Sustaining Member
I have found that my depth sounder informs me when I am aground. But I already know that.

Was stuck in dense fog in the Carolina (or maybe it was Georgia) swamps. Pulled out my Chapman, and it said that in similar circumstances you could navigate using depth contours. I picked the 10 ft contour and using the depth sounder (under power) went about 20 miles in pea soup visibility zero until reaching desired anchorage.

I have a marked line with a lead weight on the end in case the depth sounder goes and I have to get through one of the shallow semi-marked channels that typify the Chesapeake.
 
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