Suzuki 115 Correct Height?

[Karnic]

Could someone guide me in this issue please. Attached please find a YT link which shows how Outboard performs in water. My concern is regarding Correct Height. Is outboard sitting low or is it ok? Honestly im finding no issues in handling OB as it is at the mo but your feedback is greatly appreciated. WOT At 5700 RPM im getting 35/37 Knots. Pros and cons.

 

[Kawasaki]

The video looks ok
Rule of thumb
The Cavitation (aeriation) plate should align (height wise) with the 'V' at the aftermost part of the hull
You mention revs and speed but what vessel is the motor fitted on?
If you are having no 'slippage' or cavitation during tight turns at speed you wont be far off

 

[Glenlivet]

General consensus is that you should be able to see the AV plate above solid water when on the plane. By that reckoning yours is a bit low.

 

[Karnic]

The video looks ok
Rule of thumb
The Cavitation (aeriation) plate should align (height wise) with the 'V' at the aftermost part of the hull
You mention revs and speed but what vessel is the motor fitted on?
If you are having no 'slippage' or cavitation during tight turns at speed you wont be far off

Thanks for your reply. Boat is Karnic 1851 nearly 19 Ft. Outboard Suzuki DF 115. No Slippage nor cavitation so i assume as you said not far off and not worth the hassle to adjust height cos bolts are sealed etc etc.

 

[Karnic]

The video looks ok
Rule of thumb
The Cavitation (aeriation) plate should align (height wise) with the 'V' at the aftermost part of the hull
You mention revs and speed but what vessel is the motor fitted on?
If you are having no 'slippage' or cavitation during tight turns at speed you wont be far off

General consensus is that you should be able to see the AV plate above solid water when on the plane. By that reckoning yours is a bit low.

Yes thats what i taught. But doesnt seem too low neither just how i think. Bolts are sealed, Would like to know what advantages will i gain if i adjust height and if its worth the hassle of playing with adjustment height as said bolts are sealed and have to deliver boat far away to a certified Suzuki dealer to adjust:encouragement:

 

[Keith-i]

Whilst I'm sure it depends on various things, my understanding of a planing hull is that the AVP (anti ventilation plate) should be level with, or slightly above the bottom of the transom. On my rib it is about 1" above the transom and suffers no consequence.

PS cavitation is the effect of pressure on the prop causing water molecules to convert to gas which can cause pitting on the blades. The AVP is a plate to stop ventilation which is the turning action of the prop drawing water down from the surface and thereby causing the prop to 'slip'.

 

[Kawasaki]

Correct Keith
Not many understand the difference between cavitation and ventilation
Good post

 

[Karnic]

Will go up 1 hole make a difference ?

 

[Beamishken]

Going up 1 hole will gain you a little speed possibly 1 or maybe 2 mph. When we were obsessed with speed we used to keep moving the engine up untill the slippage was unacceptable then drop down 1 hole & it wasnt far off. Wether its worth it is up to you

 

[Hot Property]

The faster you go the more resistance the outboard leg has. It follows that if you lessen the leg in the water your speed will increase.

it just depends if you want to fiddle around with the height as it all costs money. If you do move the engine up say 2 holes then if you do suffer from ventilation then you could always fit a Rev 4 or Enertia prop which grip the water well. Don't forget that when doing hard turns the outboard should be fully trimmed in.

 

[QBhoy]

Despite popular belief. The av plate should sit a little higher than the lower line of the hull. Ideal range is around 1-3” above, depending on the performance intended for the set up. Most will be ideal around 1” high for all round use.
It’s hard to say from the video. Would really need to see it out the water. At first glance I’d say you’re a little low, but looking again, it’s clear you could have perhaps trimmed out a little more. Suggesting it might be just fine.
to be honest, at the level of performance likely here, it doesn’t look as if it’s going to be too far off ideal anyway.

 

[gordmac]

Quite a lot about this on the wsf boat forum.