Is the motor height going to be an issue?

[Pappy]

Your installation is fairly typical of most (not all) production installs. Neither the boat manufacturers nor the engine manufactures adhere to a strict measurement for their short shaft or long shaft engine height or transom height.
A cavitation plate an inch or so below the bottom will not be ideal but it will certainly get you from point A to B safely with no ill handling.
As has been mentioned numerous times it will benefit you to raise the engine and either do prop work or select a better performing prop.

 

[airshot]

Move that fuel tank further forward, even to the middle seat will make a big difference ! I have nothing in the rear next to the transom, everything is slightly forward and off the the sides to balance the boat. Having had that similar setup , I could never get that kind of speed from my 9.9, Maby 18 but never 20 mph. Has your been converted to a 15 hp ??

 

[S.E.R.E.NITY NOW]

To decrease time to plane, move the trim pin on your motor closer to transom.

It's trimmed down all the way. Any higher and it won't plane out.

 

[S.E.R.E.NITY NOW]

I don't know much, but I'm surprised a 9.9 will even get that boat on plane and 20+ mph seems mighty impressive. I don't know what more you could want really. If you desire more, you probably want a bigger motor.

It has to be trimmed down all the way to get on plane. One position higher and it won't do it. So it's not in the most efficient position. I don't have much experience with smaller motors so I wasn't sure if it was on par for the setup. I'll run it this season and see. Maybe go to a 20 next year but the weight difference may throw it off some. Thanks for your input.

 

[S.E.R.E.NITY NOW]

Move that fuel tank further forward, even to the middle seat will make a big difference ! I have nothing in the rear next to the transom, everything is slightly forward and off the the sides to balance the boat. Having had that similar setup , I could never get that kind of speed from my 9.9, Maby 18 but never 20 mph. Has your been converted to a 15 hp ??

No it's brand new. Just did the 2 hour break in with it then sent it full throttle to see what it would do. It's not ever going to be fast and that's ok. I just want it as efficient as it can be. If I could get it on plane sooner and be able to stay on plane at a lower speed I'd be happy. I have the trolling motor and the battery up front. There's not a lot of room at the bow for much else. I also have yet to run it with someone else up front so I will see what that's like.

 

[Stinnett21]

Check out Nauticus Smart Tabs. This may allow you to trim the motor out a notch or two.

 

[fltbtm]

So I got the boat out today to test things and do the break in on the 9.9 here's how it performed with the 1 inch lift. So the cavitation plate sits 1.5" below the transom. Just me in the boat.

Could not get on plane unless the motor was trimmed all the way down.

Steering was heavy but not unmanageable and it wants to pull to the right. Trim tab adjustment?

No water splashed in from the motor, just from my transducer I had mounted to low was throwing a rooster tail when on plane.

When on plane it maxed out at 20.9 MPH but it took about 6-7 seconds to get on plane. Not sure how that compares to other boats with similar characteristics.

I have a baseline now at least so if I make changes I guess I'll know I'd they're an improvement or not. I think I'm going to raise it up the next 1.5"

Is there any benefit to moving the engine back like a jack plate would do?

those are actually good numbers, 20mph, and 6 to 7 seconds is nothing for a 9.9 to plane on that v hull you have there. if you have the NEW merc 9.9 its a heavy 333cc motor that is the same motor as their 15hp and their 20hp. unless you got one of the last 209cc ones. if it's EFI it's the big one and there may be a hole or 2 to bolt it to the transom so you wont worry how close the clamps are to the top. i'm sure your boat is rated for at least 25hp. so when you realize you need or want more hp you can just upgrade your motor to 15 or 20 hp.. might be pricey compared to the carb motors. and no matter how light or heavy, or how big or small your boat is, move all heavy stuff like anchor, fuel tank and batteries forward and than trim your boat accordingly. if you still must plane quicker the cheapest way would be go down a pitch on the prop.

 

[airshot]

It's trimmed down all the way. Any higher and it won't plane out.

That shows your weight needs spread forward more..

 

[CincyGus]

Run it awhile and try moving weight around in the boat to see if that doesn't give you some positive effects. Will also change when you put a 2nd person in the boat so you're looking for a compromise that works well both when your solo and when you have a 2nd person, unless you do one or the other the large majority of the time. Once you figure out how she runs in those numerous situations, you may find that you want to put a 4 blade prop on to help with hole shot or performance when you have a guest. Maybe you decide you like the way it runs just like it is. Good Luck and Enjoy the boat!

 

[S.E.R.E.NITY NOW]

Great info and as a new member here very pleased with this group. Thank you everyone for your assistance.

I'd like to be able to run the motor in trim position 2. That puts the prop in the most efficient position once on plane. I'm thinking with the weight moved forward or someone else in the front seat I'll be able to accomplish that. And then trim it all the way down when it's just myself in the boat. Weather has been horrible here and things are just beginning to warm out. I'll get out there soon hopefully and try some of your recommendations and report back. Hopefully this information can assist someone else who is also new to all this.

 

[S.E.R.E.NITY NOW]

those are actually good numbers, 20mph, and 6 to 7 seconds is nothing for a 9.9 to plane on that v hull you have there. if you have the NEW merc 9.9 its a heavy 333cc motor that is the same motor as their 15hp and their 20hp. unless you got one of the last 209cc ones. if it's EFI it's the big one and there may be a hole or 2 to bolt it to the transom so you wont worry how close the clamps are to the top. i'm sure your boat is rated for at least 25hp. so when you realize you need or want more hp you can just upgrade your motor to 15 or 20 hp.. might be pricey compared to the carb motors. and no matter how light or heavy, or how big or small your boat is, move all heavy stuff like anchor, fuel tank and batteries forward and than trim your boat accordingly. if you still must plane quicker the cheapest way would be go down a pitch on the prop.

It's a 2023 9.9 carb without electric start. I heard I can change the carb for a 15 but that just burns more fuel without much change in performance.

 

[Pappy]

the 15hp carb is just like the 9.9hp carb. They are both attached to a throttle. Takes the same horsepower to move your boat at a given speed and you control the throttle. Cruise at the speed the 9.9 pushes you and fuel burn will be very close to identical. Need to outrun a storm, you have the extra power.

 

[airshot]

When you try moving weight forward, remember it does not have to be in the center. When I had my small tinnie I put the fuel tank along one side and the deep cycle battery on the opposite side, also added a piece of plywood to make a small deck area on top of each side. This kept the center open for moving around. These were just behind the middle seat. Keeping the middle open kept balance when moving around. Makes me nervous when folks move along the side in a small boat. Will be watching your progress......

 

[AlanT]

Check out Nauticus Smart Tabs. This may allow you to trim the motor out a notch or two.

I have them on my boat and think they work to plane faster and plane at lower speeds. However, I agree with the recommendations to distribute the weight first before trim tabs. At some point with smaller boats, you can only do so much weight redistribution. That was the case for my boat with a fantail. Great for fishing, bad for weight distribution.

 

[S.E.R.E.NITY NOW]

I have them on my boat and think they work to plane faster and plane at lower speeds. However, I agree with the recommendations to distribute the weight first before trim tabs. At some point with smaller boats, you can only do so much weight redistribution. That was the case for my boat with a fantail. Great for fishing, bad for weight distribution.

Yes with limited space I would like to keep the floor space uncluttered for moving around. The cooler will already take up a bit. I'll wait to see how it runs with my better half in the front seat.
What is a fantail?

 

[thill]

If your transom is pretty vertical and doesn't have much angle backwards, then it may need to be down fully.

But weight distribution means a LOT in smaller boats, and can cure a lot of issues. Sunday, I fished four people in my boat, and discovered that one person needed to be up front to prevent the bow from bouncing at higher speeds. Another time, I realized that my battery needed to be on the RIGHT side for everything to balance right. Small boats are like that.

I advise that you wait until real driving conditions before making too many changes. 20 MPH is good for a 9.9. IF you had power trim, this wouldn't be an issue, but with set trim, you just have to decide which is more important for any particular day.

Smart tabs are excellent, but I would balance the boat first. Not sure you will get the max benefit with only a 9.9.

 

[AlanT]

Yes with limited space I would like to keep the floor space uncluttered for moving around. The cooler will already take up a bit. I'll wait to see how it runs with my better half in the front seat.
What is a fantail?

See rectangle in pic. It provides storage underneath and a place to stand when fishing. The main purpose was for trawling (shimping) to manage the trawl net. It was originally 23" longer and went around the engine. I had aluminum work done to reduce the size and weight, but it still provides additional weight at the stern.

 

[Stinnett21]

See rectangle in pic. It provides storage underneath and a place to stand when fishing. The main purpose was for trawling (shimping) to manage the trawl net. It was originally 23" longer and went around the engine. I had aluminum work done to reduce the size and weight, but it still provides additional weight at the stern.

Nice rig.

 

[AlanT]

Nice rig.

Thx.

 

[S.E.R.E.NITY NOW]

Just an update for anyone who followed this and assisted me with getting things setup correctly. Maybe the info can help someone else too.

The 2022-2023 mercury long shafts actually measure just over 22" by the manufacturer specs. Not 20" as usually stated on most specs found online.

I ended up installing a fixed jack plate giving me 2.5" of height (mounted it .5" low to clear the cap on the transom normally it would have been 3" rise) and 4" set back. Made the 9.9 sit perfectly even with the bottom of the transom. But not thinking about how low the clamps sat they hit the top of the transom so couldn't tighten it down. Had to put in a half inch shim to get the clamp bolts to clear. If I had mounted it that half inch higher over the transom cap I would have been fine.
At this height everything performed perfectly exactly what I needed. With just me in the boat I got it to 21.7 mph and would stay on plane down to 15.5 mph. But as soon as anyone else was in the boat that was out the window. Maybe got to 13mph and would not plane. So naturally the next option was to repower and step it up to the 20 HP.
Shaft length is the same as the 9.9 but the clamp bolts actually sit half an inch higher than they do on the 9.9 so the spacer was no longer needed but I found it ran well at that hight so I left it in.

I spent more time on this than I should have. Knowing what I know now with the assistance of everyone here and some other groups I would have just done the jack plate off the start. Hopefully this helps someone in a similar situation and saves them time.

Also, if your motor isn't at least 70% of the max hp your boat is rated for you're probably going to wish you had gone bigger. Do it off the start. I should have just gone with the 20 or at least the 15 off the start. Lesson learned.

The extra 34 lbs of the jack plate and bigger motor combined and being 4" further back has caused it to ride bow high when it's just me and trimmed all the way down. Which is one drawback but I think I've sorted that out with weight distribution. With some gear and 4 people in the boat it hit 25mph and sat pretty level. With just me I saw 33mph before I had to shut it down due to the chop was bouncing me around in different directions. Need to sort out the stability at speed but otherwise I'm happy with how it all turned out.

Big thanks to the group for helping me out. Learned there's a lot more to it than I had thought. I'm happy and most of all the family is too.