No Speed reading

[Warren]

On a recently purchased Cat 30 the speed indicator stopped working. I have electrical power and it worked for two weeks after launch. I would assume it is a defective paddle wheel or it is already fouled. I do not have an owners manual, but it is a Standard Horizon model (round face). Is there a way to access the wheel without going under the boat? I do have access to the top of the instruments.

 

[John]

Check to see if there is perhaps a small bilge compartment in the forward cabin (or some other location). On my 350, this compartment contains, among other things, the speed transducer. It is removable and can be replaced with a blank plug when the boat is not being used. This keeps the impeller from getting dirty or encrusted with marine growth.

 

[RonD]

Speed Sensor

The paddle wheel is rarely defective but typically gets fouled with marine growth. Mine tends to grow a "beard" of seaweed (generally filled with brine shrimp!) unless I use the boat often. An old toothbrush is good for cleaning it. Just make sure the wheel spins freely, and the exposed wires don't appear cracked, corroded or broken.On the Raytheon ST60 Speed sensor, the procedure is pretty easy, as the paddle wheel assembly can be unscrewed without flooding the boat ( it has a little flapper valve built-in to slow water flow). On others, you have to be quick to insert a plug to stem the gusher.The Speed & Depth sensors are often located in a bilge area just forward of the keel. On my C320, that's in the forward cabin under the lift-up sole panel. The speed & depth are side-by-side straddling the centerline.On some boats, I've seen the speed sensor mounted on the lower edge of the bow, too. Much more awkward, vulnerable to damage, and the water flow there might not reveal a true speed-through-water.An alternate speed indication is your GPS general speed-over-ground (SOG) readout. Just remember it is not the same as the speed-through-water readout you get from the speed paddlewheel sensor, or velocity-made-good (VMG) from GPS acting upon a route or waypoint setting.--RonD

 

[Joe]

diaper rash ointment

...I've heard that spreading a thin film of Desitin, or any "diaper rash" type of ointment, on the sensor paddles will inhibit growth on them. Anyone have any experience with that? I keep the hole plugged most of the time, only use the sensor on occassion. Some water will come in the boat, but if you're careful and ready with the replacement it'll be less than you think. What is a revelation is how fast it could come in if left unchecked.

 

[Robert]

If the sensor is mounted ahead of the keel

try dropping a length of rope, holding both ends, allowing the loop to envelope the hull. Work this backward toward the keel. With a gentle side to side motion of the rope, you may be able to clean the impeller of enough growth to allow it to work. Doing this occasionally is not only good for the impeller, it entertains your neighbors for awhile as well!G'luck

 

[Jim A]

This winter when the boat is out

of the water, take the through hull out, remove the impellar and pin and clean them real good. Use a nail to push the pin out.Or get a GPS.