How often does your pitot tube get clogged?

[riptide09]

While I realize speedometers that use pitot tubes are not so accurate I like mine to function. That said, how often does you tube get clogged.

I installed a new tube on my boat over the winter.

After only 17.5 hours of run time my tube is clogged again. This seems kind of quick. Any hints/tips on how this can be avoided.

 

[Thajeffski]

Re: How often does your pitot tube get clogged?

Mine has never clogged....... are you in really dirty water? or maybe hitting the bottom a bit?

 

[riptide09]

Re: How often does your pitot tube get clogged?

I bought the boat last fall with a clogged tube so I really can't comment on what happened prior to my purchase.

I don't believe I am in really dirty/cloudy water. I only put the prop in a little of sand one time which resulted in minimal paint removal from the prop but no structural damage.

When it clogged earlier this week I was in the Songo River in Maine. I did get into a bunch of plants when I moving around and waiting in line to go through the locks back towards Brandy Pond. I did have to raise my OB and clean all the plants from the lower unit however I am sure the speedometer quit working before I hit those plants plus I was basically just maneuvering for position at idle.

I am going to try and blow the tube out with compressed air tomorrow and see what comes out. I sure hope I don't have to replace it again as it was a lot of work stringing the tube. If I do, I will string 2 or 3 at the same time so I can just swap tubes in the future plus if I string an extra tube Murphy's law says I won't need it.

 

[stubbsboogie]

Re: How often does your pitot tube get clogged?

Mine clogs every couple months. We are in a very sandy area and it just happens. Last time it clogged it was a bear to clean out bu most of the time it is just a quick fix.

 

[Thad]

Re: How often does your pitot tube get clogged?

Mine has never clogged either. And I consider the water I primarily boat in to be very dirty. But, the way I have always looked at the speedo on the boat is, it's only real purpose on the boat is to fill the space on the dash opposite the tach.

Mine, from day one, is as accurate as an old musket

 

[JimS123]

Re: How often does your pitot tube get clogged?

I hit a soft piece of wood once. It kicked up the pitot and clogged the hole. Blew it out and all was fine. That was about 35 years ago. Never had a problem before or since.

I can remember reading Powerboat Magazine test reports back in the '80's. They always tested the speedometer accuracy and found them to be + or - 1 mph. Of course those were oem units like Teleflex or Airguide. My personal experience would confirm that good accuracy. The 2 pitot units I currently have are 28 and 60 years old. The "new" one has never been serviced, though the "old" one had a new hose put on a few years ago. The circa 1952 tube is original. They are both spot on GPS.

Are you sure the pitot tube is clogged, or do you just have water in the hose. Did you replace the tube or the hose? Remove the hose from both ends and clear out the water. Then clamp one end shut and make sure the hose doesn't leak air. Ditto blow out the pitot tube to be sure its clean. Don't mess with the hole in the brass fitting - reaming those out with wire is the usual source for inaccuracy. When you put it back together coat the hose barbs with silicone sealant. If it sealed tight it should work for years! If you truly are geting debris up the tube on a sealed unit, your water is just too dirty for this application.

 

[Don S]

Re: How often does your pitot tube get clogged?

This thread is almost 2 years old brought up by a spammer. I would bet money he has fixed it since 2010, and it's time to let this thread sink back into the archives.