What is this doohickey?

[chriscraft254]

Re: What is this doohickey?

Yes, the pitot gets angled down, so it is dragged through the water. There is a tube that runs to the speedo on the dash. This will give you your aproximate speed because they are not very accurate. .

Ok, that explains the part on the bottom that flips up and down. (and there is mention that it may be an extendable one due to its current mounted height). Now that we know what this is, can you tell me how it works? When I am in the water do I flip down the bottom piece and I'm ready to go?

CC as for the cracks in the transom...I think I will have a chance to do a drill test today so I will study it with a close eye to check it out for sure and see what kind of shape it is in.

 

[smokeonthewater]

Re: What is this doohickey?

Generally they stay down all the time unless they hit something in the water

 

[JimS123]

Re: What is this doohickey?

Its an old style pitot tube made out of cast aluminum. They were easy to flip up when you trailered or hit something. The issue though is that there is no mark on it to direct you to position it at the right angle (parallel to water).

I haven't seen one like that in many years other than mine My '52 has one just like it. With a sealed pressure tube and the right position, it beats the heck out of my GPS.

One of my favorite spots in the river has a 12 mph current. If I head upstream and set the throttle to just meet the current, my speedo says 12 mph but the darn GPS says I'm standing still. Burning a heck of a lot of gas for standing still!

PS - if you get a chance to take a pic of the dashboard unit I'd be interested to see it. Those are classic parts that are sought ater by collectors.

 

[Philster]

Re: What is this doohickey?

If you are going against a current of 12 MPH, and your offsetting it perfectly with x am't of power, your speed over water is 12 MPH via the pitot speedo and the GPS should read 0.

The GPS is the best indicator of how fast you are going to where you want to go. GPS is better for navigation. These are boats. Navigation is kind of important -- ya know?

A well-performing boat pitot-style speedo is the better indicator of how your boat is performing.

The GPS most accurately reflects your progress. Head down with a current of 10 MPH in a boat that hits 50 MPH at WOT as speed over water and the GPS should read 60. Your boat's top speed for the sake of registering performance is 50 MPH. The GPS is going to be more accurate for navigation calculations, because you are headed to your destination at a rate of 60 MPH.

GPS for the win, just not when you need speedo readings for tuning....

 

[duhmey]

Re: What is this doohickey?

Its an old style pitot tube made out of cast aluminum. They were easy to flip up when you trailered or hit something. The issue though is that there is no mark on it to direct you to position it at the right angle (parallel to water).

I haven't seen one like that in many years other than mine My '52 has one just like it. With a sealed pressure tube and the right position, it beats the heck out of my GPS.

One of my favorite spots in the river has a 12 mph current. If I head upstream and set the throttle to just meet the current, my speedo says 12 mph but the darn GPS says I'm standing still. Burning a heck of a lot of gas for standing still!

PS - if you get a chance to take a pic of the dashboard unit I'd be interested to see it. Those are classic parts that are sought ater by collectors.

Ask and you shall receive:

 

[smokeonthewater]

Re: What is this doohickey?

If you are going against a current of 12 MPH, and your offsetting it perfectly with x am't of power, your speed over water is 12 MPH via the pitot speedo and the GPS should read 0.

The GPS is the best indicator of how fast you are going to where you want to go. GPS is better for navigation. These are boats. Navigation is kind of important -- ya know?

A well-performing boat pitot-style speedo is the better indicator of how your boat is performing.

The GPS most accurately reflects your progress. Head down with a current of 10 MPH in a boat that hits 50 MPH at WOT as speed over water and the GPS should read 60. Your boat's top speed for the sake of registering performance is 50 MPH. The GPS is going to be more accurate for navigation calculations, because you are headed to your destination at a rate of 60 MPH.

GPS for the win, just not when you need speedo readings for tuning....

Yeah well, If you were to be towing me on skis or a tube on the river you d@mn well be using WATER speed instead of ground speed..... YA DIG?

 

[Silvertip]

Re: What is this doohickey?

In a river the pitot tube could be registering 2-3 mph or more with the boat standing still or vice versa if going downstream. GPS would always be correct since it is speed over ground not speed over the bottom.

Is not the bottom of the lake/river/ocean the same as speed over ground? Of course it is. The water in a river for example is moving at a given speed over the bottom or parallel to the shoreline (same difference). To illustrate this, anchor in a river with a 5 MPH current. GPS will show zero MPH (or at least it should since you are not moving). A Pitot speedometer will register 5 MPH (if it is capable of measuring speed that slow). Going downstream at 5 MPH as registered on GPS will result in 0 MPH on the speedometer since the boat and the water are moving at the same speed.

 

[JimS123]

Re: What is this doohickey?

Yeah well, If you were to be towing me on skis or a tube on the river you d@mn well be using WATER speed instead of ground speed..... YA DIG?

Yupperrrr......fer sure!

I just get a kick out of it when someone asks a question about speedometers and without a doubt some young tecnhnogeek will tout the GPS as the ONLY way to go, further staing that old fashioned pitot tubes are useless and inaccurate. Obviously, both have their place, but to use either one requires the knowledge of the difference between land speed and water speed. I know some that can't grasp the concept!

 

[QC]

Re: What is this doohickey?

BTW, those old Airguides are damn good if they are working properly . . .