Do you actually have a 16" plate or a shorter plate with spacers?
Do you actually have a 16" plate or a shorter plate with spacers?
BULLET 20 XRD/250 Merc Sport XS
www.ncboatguy.com
I feel no spacers my guess is it's a 15" setback plate that is being measured flat across the top not perfectly perpendicular to the transom angle.
Yes. It is all Jack play no spacers
- Nichols
MemberJoin DateJul 2015LocationChattanoogaPosts130
#912-17-2015, 11:01 AM
You do get more lift to a point, but the further you go back the higher you have to run your motor or you will run slower due to more drag(when the water leaves the pad it rises). Your prop when close to the surface is getting a mixture of water and air, when you have more setback you are making the boat longer(the motor is further from the bow) which makes the prop have a harder time picking up the ''longer'' boat and pushing it down the lake. If more setback is better why not just put a 20''-30'' jackplate on it...lol. The negative effects outweigh the positive in my opinion. When adding more setback your getting cleaner water to the prop and changing the fulcrum point of the boat, but the prop is main issue. The longer boat the harder it is to lift.
I also have a 21xrd/250xs and I run 16.5" setback on mine, it will not carry the nose with less when it is loaded full of tackle,fuel, ice, and 2 men going fishing unless you bury the motor. I know because I tried. Before my power poles I could run over 90 easy solo once I got it sort of dialed in. Even now with 2 10' power poles on it it's ran 87 loaded solo and its a bone stock 250. I haven't seen anyone running those numbers with a 250 and poles before, most don't without poles.. I run it because I've tried all of them, from 12" to 14" to 16.5". With my boat and my load and tackle placement, the 16.5" just works. I could move all my tackle to the rear and prob run less, but that would suck to fish out of and I bought it to fish. All that being said, a 21 will typically run with the nose higher more so than a 20 from what I've found so far, you kinda have to fly the nose to get anything out of them. It should drive fine with 16" but with a TM gearcase you should be able to run less and do the same thing up top plus have a better holeshot. A TM has no problem lifting a big long boat like a SM does.
Mike, what you just wrote was the main reason I linked that post from Paul. I would never presume to put words in Paul's mouth but, to me he is saying the jack plate serves two main purposes. First it provides an easy way to adjust the prop centerline relative to the bottom of the pad. Second it provides a way to get the prop back from the end of the pad into better water. With a Sportmaster the norm is to run prop centerline above pad. This puts the prop at or above the surface. Putting that prop in better water further from the pad allows the prop to have better water giving less slip. However as you move the prop back it makes the boat longer making it harder to lift the front end. To a point Paul seems to think the better water offsets the longer boat. Once you get past that point you will be losing ground. Since the TM runs deeper I understand Paul's point that less setback (I think he thinks about 14 inches with the TM) is probably better in that the prop is deeper and in better water per amount of setback. Less setback makes the boat shorter and easier to lift the bow. I do know a SM can be made to work on a 21SS (I know a different hull) with a 300. But, I know according to Jerry (owner of the 102 MPH 21SS) it is weight sensitive. He had his son, and my son in the boat one time to get a specific camera shot and he told me it was blowing out pretty bad. Paul does state that if a SM is on a 21XX it must be run light to work.
I always find Paul's posts enlightening and very informative.
Ronnie I think the main reason for the blow-out that day was due to engine height,I was running 2 3/8 above pad and Jeremy was sitting forward in the boat,the set-up was for top-end and when we put about 400lb. more along with my ballast it wouldn't hold.The hull is weight sensitive,but not as bad as it was that day,when you went by I gave it a little gas and it was just like giving a car gas on ice,it just spun out.
My point exactly. The SM works good on your boat set high. You could of course lowered motor or got lighter. Obviously if you wanted to give up a couple MPH you could lower the motor and carry a heavier load. Power ain't your problem in any situation. Just need to the prop to hold the power<grin>
I appreciate all the input. I am a little OCD about getting my boat right or at least get it the way I want it. After that I will usually leave it alone and just go fishing. Checked it today and I was 1.75 below the pad. Brought it up to 3/4 below and will try it there.just had this motor put on and had not checked it properly
Replaced my steering helm and I think I fixed my issue. The old one needed check balls cleaned so I wanted tilt anyway and if I was gonna have to bleed system I thought I would just replace it. Drives much better and doesn't drift any to one direction
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