20HP motor , prop & boat ?

first the equipment 2010 Tohatsu 20HP long shaft factory prop 9 inch pitch
Alumacraft navigator 165 boat weight is 980Lbs empty The boat has a wide beam 93 inches and is 91 inches wide at the transom motor weighs approx 120 lbs 1 group 27 battery in back and 1 group 27 size battery up front usally keep 10 gallons in the rear gas tank it is a tiller steer so add my 230 lbs to the back of the boat.
 
I thought the boat might be able to go about 15mph Top speed is 9.3 MPH on GPS, motor will only spin at 5000RPM also motor is set on the lowest trim rod setting to help push the bow down.
 
Question is, will a shorter pitch prop help the MPH and motor RPM? the owners manual says select a prop so that you have a RPM of 5400 to 6100 at WOT Also any ideas on how to get bow down for a more level ride.

I would assume that @ 9 mph your boat is not getting up on plane. Going 1 pitch lower on your prop should gain you about 200 rpm's or so. I'm not sure @ what speed your boat will plane out, but I had a 16.5' ft Deep-V Princecraft w/ a 20hp. Yamaha 4 stroke and it would do about 18-20 mph @ wot. If I remember right it would jump on plane right around 14-15 mph. Once you get your boat up on plane the bow of your boat will level back down.

I would reccomend that before you go out and buy a new prop that you try and raise that motor up one or two holes. By leaving it in the lowest position you effectively have more drag on the engine during running. This will also contribute to your engine set-up not obataining the max rpm's at wide open throttle. As was already mentioned, try redistributing some of the weight in your boat. Smaller boats can be sensistive to this, especially when you are right on the threshold of having enough motor to put your boat up on plane.

If your gas is in the 6 gallon remote tank, simply try moving it forward. Sounds like you have alot of weight in the rear of the boat. When I was by myself in my aluminum I would move the tank as far forward as the gas line would allow, boat planed and was fairly fast for a 9.9. Also agree on moving lifting the trim stop and experimenting with that. You'll have to be careful changing props, it sounds like you are just on the edge of planing and that rpm will jump quick once she get up on plane.

Actually that's what I meant, raise the trim angle. It will lift the bow early but should put less drag on it and allow it to plane out. If you can get someone fairly light to try it once to see if it planes out for them. Someone 100 or so pounds lighter. At least it will give you an indication of what you need to do weight distribution wise.

Trim planes?
Add a few wedges underneath boat at transom
2" high 6" long 10" wide on both sides

There have been a couple of threads on the subject, here's one

http://forums.fishusa.com/trim_fin/m_316379/tm.htm

batts in front keep the bow down if the option is there my 16ft has a 35hp long 2strok and its slow i mean faster than walking speed around 10mph but boat has counsel/2 batts 12 gal gas 1 bow mount 55lb one stern mount 44lb and a anchor in the bow so i think you would need a 25hp or little larger

Thank you for correcting me, I was so amazed at your superior knowledge, I had to go get the paperwork from my boat purchase on July 6, 2001 at which time I purchased a 2001 Sylvan 17' Bass Boat, 25 elpt 25" shaft, Mercury Stainless Prop, 2 Humminbird 400TX Sonar Units, one mounted on the dash with a transducer switch to select the standard tri-beam transducer or the side shooting transducer which are both mounted on the transom along with the speed and temp sensor. I had a MInn Kota 55/12 Genesis installed on the bow with a side shooting transducer mounted to it for the forward deck mounted 400TX. My boat has gas actuated trim tabs installed and it also has first BayStealth Hydraulic steering unit installed. This boat was purchased and rigged at EMI Marine Center in Hanover, Pa. I was the General Manager at the time and had a very good relationship with all my suppliers and was able to research and get precisely what I wanted and much of these goodies were either given to me to test for the manufacturer or I purchased at cost. I am glad you know so much more about my boat then I do. I stand corrected and do apologize for giving such misguided information. I will make sure I never respond to anyone again since I apparently don't know anything.

Ummm Dave... fryem is referring to Side Imaging sonar, not a side shooting transducer (which has been around for 15-20 years). You're kinda coming off as a bit of a child here. I don't think he was scolding you or calling you a liar...just pointing out that what you have on your boat must be different than what he has, because side imaging sonar did not exist before 2005.