How does raising the engine raise prop efficiency

[sceptre]

I have heard people talk of raising the motor to gain efficiency, does this reduce slip somehow?

 

[Silvertip]

Re: How does raising the engine raise prop efficiency

Less motor in the water the less resistance there is. Less resistance, more RPM. Only works to a point though and you begin to lose water pressure and/or the prop loses bite -- especially in turns.

 

[Haut Medoc]

Re: How does raising the engine raise prop efficiency

If you are talking about "Trimming the motor up", it reduces the amount of hull in the water, thus reducing drag....Rpm's will increase as the engine does not have as much resistance.....As Upinsmoke says it only works up to a point....<br />BTW, welcome to iboats .....JK

 

[gatorred]

Re: How does raising the engine raise prop efficiency

I use jackplate and step it back 6 ins and stainless steel prop <br /><br />here's a write up i found from (Land & Sea) <br /><br />Hydro-Electric Transom Why Jack an Outboard?<br /> <br /> why a Jack Plate is the first performance option to install!<br /> The optimum height relationship of the propeller to the bottom of the boat is dependent on many outside variables. When operating at low speeds or trying to carry a heavy load, a lot of blade surface area in the water is required. This means that most of the prop must be below the bottom of the boat. At high speed on a good performance hull, however, the blade area requirement is much lower. By raising the engine mounting height, part of the prop (and the gearcase) is lifted out of the water, GREATLY reducing drag. Speed improvements of over 10 mph are common when going from one extreme to the other.<br /><br />Currently, the better designed hulls and props achieve their maximum top speeds with typical transom heights of 26 " - 29". Since it is difficult (sometimes impossible) to get a loaded boat on plane with the engine permanently mounted that high, the use of a hydraulically adjustable transom jack lets you enjoy the best of both worlds. It gives you the ability to set your outboard in the full down position for getting on plane, pulling out skiers, low speed cruising, or drag racing take off. Once the boat's speed increases, the unit can be raised to the most efficient tran­som height for the prop's load. Without a hydraulic tran­som, there is just no way you can even think of running your prop's optimum transom height and still have an enjoyable family ski or pleasure boat.<br /><br />With a hydraulic transom and infinite dash control of its travel, you can find the best combination of installa­tion height, trim angle, and prop in minutes instead of weeks (without making "Swiss Cheese" out of your tran­som)! One also makes the normally difficult job of safely jacking a big V6 engine on a 20" - 23" transoms a cinch.<br /><br />As you have probably gathered, a Land & Sea Hydro-­Electric Transom is simply one of the best accessories you can add to your bass, drag, or ski boat.<br /><br />Professional bass fisherman and six time B.A.S.S. Classic Finalist Charlie Ingram, the only angler to ever win three Bass Angler Sportsmen Society Tournaments in one year, picked our Model-600 for his tournament rig. He says "No serious fisherman can afford to be without the land & Sea hydraulic jack plate . . . The Land & Sea plate is the best plate available, with all pumps and lines securely protected from docks and stumps and other under­water obstacles. Land and Sea is the one for me."