How far below the bottom of the boat should the prop be

If you have a short shaft motor the top most part of the transom and the lower most part of the boat should be about 15 to 16 inches. 4 Measure from the ground to the center of prop shaft Write it down.

All outboards are different in this regard.

How far below the bottom of the boat should the prop be. How far should the prop be under the boat You will start with the AV plate plate right above the prop even or slightly above the keel when the plate is parallel to the keel. How high above depends on the technology level of a given prop and how it reacts to your particular hull design. How far below the bottom of the boat should the prop be.

If you have a short shaft motor the top most part of the transom and the lower most part of the boat should be about 15 to 16 inches. For a long shaft I think 20 to 21 inches is correct. Prop shaft height On slower boats running the prop shaft a little deeper in the water will give you a little mechanical advantage to lift the bow up a little higher and free the boat up for more speed.

Heavier boats usually need the prop a bit lower to lift the bow. On 19-21 V bottom boats usually around 3 below the bottom is a good place to start. The prop should be well clear of the bottom of the fin in the event of a grounding.

The prop should swing at least 6 above the lowest point of the fin to prevent it eating a lot of bottom when trying to back off after a grounding. Water flowing from under the boat rises so if the prop is further away from the transom it may be possible to mount the engine higher. All outboards are different in this regard.

For example a Mercury Verado positions the propeller about six inches further aft than a Mercury OptiMax outboard. A boat riggers rule of thumb is that the motor can be raised one inch for each eight to 10 inches. However the motor should not be raised more than 5 inches above the standard position.

Raising the motor increases the speed of the boat while decreasing the effort needed to turn the boat. The bottom of the plate should be at or above the top of the straight edge. Thats the quick and easy way to get yourself on track to finding the right outboard mounting height.

Since the goal of your anti-cavitation plate is to prevent surface air from being sucked into your prop it is designed to be at a certain height. The anti-ventilation plate should ride on the surface or slightly above the surface when the boat is on a fast plane. The height can only be determined by testing as the setback of the motor also comes into play.

There is no hard and fast rule. The relation of the propshaft to the bottom of the boat is not important in a not for racing boat. An old rule for Cav Plate position.

Is to start with the cav plate even with the bottom for 30-40 mph 1 inch above for 40-50 2 inches above for 50-60. This is a fairly conservative rule but at least puts you in the ballpark. When you hear the term below the pad its is how far the center of the prop shaft is below the very bottom of the boat yours does not actually have a pad.

The pad is the very bottom section of the hull on riser hull. I dont think yours has a riser hull. The is measured by leveling the bottom of the hull and motor and measuring it.

Then you can trim the motor up or down rotate in small increments to get the best performance from it. If you have a short shaft motor the top most part of the transom and the lower most part of the boat should be about 15 to 16 inches. For a long shaft I think 20 to 21 inches is correct.

The Mercury Verados propellers distance from the boat bottom is about 6 inches further aft when measured against the propeller distance for the Mercury OptiMax. However the standard recommendation is that for every 8-10 inches distance between the propeller and the transom the outboard motor should be elevated by an inch. 4 Measure from the ground to the center of prop shaft Write it down.

5 Deduct the two measurements. You want the prop shaft 3 12 below the pad of the boat. 6 Adjust the jack plate up or down paying close attention the water pressure and max.

7 On lighter hulls with low water pickups running at a neutral trim angle is best. On faster vessels the anti-ventilation plate is often located two to three inches above the boat bottom but putting the engine higher may result in poor cooling water intake and an overheated engine so care must be taken to locate the engine correctly. In this manner how far below the bottom of the boat should the prop be.

If you have a short shaft motor the top most part of the transom and the lower most part of the boat should be about 15 to 16 inches. For a long shaft I think 20 to 21 inches is correct. For a cat you want to start with the bottom of the prop hubdrive dog to be level or slightly above the bottom of the sponsons.

For a mono you want the bottom of the prop hubdrive dog a couple mm bigger boats more mm above the bottom of the V. On a 25 hull youre looking at about 3-5mm typically. If the Prop is significantly lower than the bottom of the boat it acts as a drag.

Since it looks like you have a flat bottom boat which is what I have for my electric only boat think about how far below the flat bottom the prop is. Basically you want all the water that the prop is pushing to glide ride under the boat. How do I determine if the kicker should be 20 or 25.

I had a 20 on it previously and it worked fine as far as I could tell but I never knew if that was correct for this boat. The 20 kicker prop was always below the bottom of the boat seeing it was mounted to the side and the sides of the hull are shallow. Old 15 Clearance Rules - 15 rules came about many years ago when external transducers were 1st installed on inboard boats.

15 was simply a barometer used then and now to install a transducer aside 15 from the outside diameter of an inboard prop in an effort to avoid interference from the aftward thrust of water. Is the prop wash hitting up against the hull of the boat counter productive or should it pass under the boat. I dont believe its a factor while your fishing prop isnt spinning fast enough.

If you put it on high to run across a bay it might. On average for single stern drive boats propshaft centerlines may vary between 8 or 9 inches to only 3 to 5 inches below the bottom at the transom. A nine inch propshaft depth 13-12 Inch X-dimension for a standard Mercury Bravo 1 would be considered a conservativedeeplow set-up where three inches below a 19-14 inch X-dimension would.

Outboard jets work best on flat-bottomed boats with a bottom width of 48 inches or more. This is a frequently used axiom and has led to a lot of misconceptions. The shape of the hull cannot be easily defined.

Fact is when it comes to bottom width the wider the bottom the more wa-ter it displaces. Because a shallow draft is important the. They are mounted flush with the bottom.

The strut is mounted on the centerline of the boat and the centerline of the prop shaft should be about ¾ below the bottom. The rudder is mounted 3 to the right of the strut and the rudder bottom is 3 below the bottom of the hull. On this boat an finned strut was used.