*** 23' Sceptre / Tsunami Engine Height Set Up *** How High
 

Hey Guys,
What height are you running your Cavitation plates on your 23'
Sceptres. I have seen a couple posts saying that this hull likes at
least 2 Inches High above the bottom of the Hull... I am wondering
if its possible to get Great Performance with the right prop at 2 1/2".

WHY? I am having a hell of a time finding a 25" shaft motor in my price
range. I can grab 200 and 225 hp motors all day long at 20". I have
an enclosed transom and 29" Stainless Marine Setback Bracket with
flotation. If i could get through this season with a Decent 20" Motor
then Next going to Spring and put on a Reconditioned 300hp Evinrude
Etec.

Ideas...Thoughts... I know the engine is sitting low, but... If it will work its
better than dropping the $900 to install the bay Extension kit... or the
10 hours to swap out exhaust housings and gearboxs.

Let me.. Know your Cavitation Plate Height.. along with Engine Set Up and Prop... with Prop Pitch/Diameter.

Thanks in Advance Robert

Spent about an hour looking at 15 plus Seacrafts with Brackets. I can't help but think every last one of them was set up improperly. I did not find one on a bracket that was not bolted in the very top hole. This leads me to believe that almost every motor is set up too Deep...

These are all 23' footers...

Really starting to think that adding a 20" in the Top Hole on my Bracket should be close to perfect for Height... The only thing I am giving up is a measly 2" of Engine height to the water line... Not seeing it as a big deal...

Love to hear some feedback from Guys...

Thanks

The issue you will run into is when you pull her off a plane and the backwake buries your motor. Brackets make it even worst. You are much better off continuing your search for a 25" if not a 30".

Thanks for the input Moose. Your boat looks like the cavitation plate is almost flush with the bottom...
or are you up some above it...?

Appreciate it...

Robert

Two inches above the bottom but I am running a 10 inch offset plate that allows me to adjust motor height with just a wrench. I am also running a 30 inch motor which keeps her nice and dry.

Moose.. Thanks for the Reply... So the question remains now...are you still too low...? with 10" of setback you should be able to run 1" higher than normal from boat swell, then add 2" for the way the seacrafts like to run.

Now I am curious as hell to see how high a guy can really run one of these engines on a 23' without prop blow out... and the best overall performing prop.
Thinking this is going to be a little science.

I looked at a ton of 23' sceptre pictures online and almost everyone of them was flush with the bottom of the boat and most were running non-performance props. How much have you monkeyed around with your engine height set up and prop selection?

Robert

Herds of Monkeys have been unleashed on my boat developing set up. But unless you are running the exact same set up, none of my specs will likely be close. My motor swings a 16x20 3 blade. That is very specific to the gear set and brand of motor I run and also drives the height I am able to run without turning blowout or cavitation and slippage in different sea conditions. The tipping point for having the motor mounted too high is not a blurry line that is hard to find and unless you are running your boat on a glass flat pond, don't be thinking you will be able to get away with a 20 inch motor..... because you won't without putting a snorkle on it.

Thanks Moose.. Exactly what i wanted to hear... ur boat tuned for your engine with height and prop and load... and No worries.. not getting a Snorkel for 23' think i found a 25" yamaha today...:D

Robert

FWIW - I talked w Ken at PropGods about the same question for my 23 Sceptre I/O. He suggested at least 1" above the bottom and probably closer to 2". Don't want to hijack Robert's thread but I'm probably going for ~1.5+" (since an I/O is kinda hard to adjust).

I think you'll need to be quite a bit higher if bracket setback is 29". Not sure how much this applies to a 23, but I've found that the "raise motor 1" for every foot of setback" rule-of-thumb that's often quoted for brackets is WAY too conservative for my 20! Optimum motor height per BRP is when the AV plate is above green water when you're up on plane and fully trimmed out. Picture below shows the AV plate on my 25" motor at 3.5" above keel BEFORE I had Don Herman redrill the motor mount holes on the bracket to raise it about another inch! And it's STILL too low! Needs to come up another inch for top of AV plate to be above green water, so that would put me somewhere around 5-5.5"! I have to admit that I only picked up about 50 rpm and 0.5 mph with the last raise so another inch might not make much difference, but I'm sort of a perfectionist when it comes to engine performance, so it kinda bugs me if there is any more splash and drag than necessary!

Bushwhacker your exactly right... with the Setback I have used 3.5" on a 30 Inch Bracket... Since i have not launched my Tsunami Yet... Just picked up the Engine Tonight for it... My Bracket is mounted at 28" then i see these Seacrafts like another 1.5 to 2.5 inches to run... Then the AV plate can be raised even more... Basically until it Blows out then down One Hole... with that being said...

I just got my hands on a Land and Sea Electric 4" Jackplate to place onto my Bracket...then the motor. I am going to just set it up in the 2nd from the bottom hole basically up 2" then i will have the The opportunity to run it up another 6 inches once on plane. Drilling and Installing Water Pressure gauge as we speak...

Really Appreciate the input... Want to just get this close the first time.

Regards,
Robert

My Stilletto is 2 1/2+ had it up another hole which would have put it at 3" but lost some trim response but it didn't cavatate, they like the higher the better. You would need a 17 they are hard to swing

Dog... It's a Johnson 225 1986 .. the 2.7 liter.

So are you thinking i can run 2.5 high with the Stiletto with that engine... and then add 3 inches for the 30 Inch set back bracket? making it a total of 5.5 inches up from the bottom with no issues and could go as high as 6 inches?

14 1/2 x 17 Stiletto Advantage.. Appreciate the input.. Bushwhacker said you had done some extensive testing on this...

Appreciate the feedback.

When you say Hard to Swing... you mean?

Thanks In advance Robert

Some props are harder to turn than others. Blade shape and blade area, rake, cupping and of course pitch all factor into how much resistance the water forces on the prop. Weight and hull shape, as well as power also influence prop selection. Height of the motor affects this, too.

The Stiletto has a lot of cupping and aggressive rake as well as plenty of blade area. Less power and more weight will require less pitch than what ESD is running, that's why he is recommending a 17 pitch vs the 19 he runs. The cupping is what allows ESD's motor to run so high without blowing out.

Keep in mind your going to have a lot more weight forward with the cuddy and seats forward and all the stuff you'll likely be putting up there so you're likely gonna being riding higher aft anyway.

Cav plate should be just above water when on plane, at speed, and when trimmed out at least 1/2 way to fully trimmed before the prop starts to lose its bite.
IF motor cav plate is under water when trimmed out running, then it's creating extra drag - it's pushing through the water, pulling on your transom, and slowing the boat .....

Like if you put your hand under water flat, and turn as fast as you can go, then angle your hand and try to keep it under water - you'd feel the drag under the water. Same for outboard.

Interesting that many marina's, dealers etc rig a bit too low......

I raised my 200 E etec and it's better, I may even go another hole - UP.
Don't sweat it if you change the position once or twice.