Minimum Planing Speed & tabs

[Ekea]

what is your minimum planing speed...

1. with engines trimmed all the way down and tabs fully up (not used)?
2. with engines trimmed all the way down and tabs fully down?

 

[Hookup1]

I can barely plane at about 15.7 knots, no tabs, twin 4-blade props.

It was 20 knots before the prop change.

new prop

So, many years ago I had a power tec OS4. It gave my boat better stern lift, hole shot, mid range cruising performance,better following sea performance and reverse at the dock. I repowered in 17 and had it on it. Then some thiefs decided they wanted the prop and took the motor too. My new...

www.greatgrady.com

 

[seasick]

Too many variables to give a simple answer. In addition, do you want to know the speed stay on plane or the time to get on plane?

 

[family affair]

With a light load and no tabs 8-9 mph. Never tried with full tabs. Naturally I would expect anyone to call BS, so here is the photo:


Edit: Looks like I didn't have the engines tucked all the way in. I'll try to grab another photo next time out with engines all the way down.

 

[seasick]

With a light load and no tabs 8-9 mph. Never tried with full tabs. Naturally I would expect anyone to call BS, so here is the photo:
View attachment 34757

Edit: Looks like I didn't have the engines tucked all the way in. I'll try to grab another photo next time out with engines all the way down.

The speed to stay on plane is a function of the thrust as compared to the drag. The hull speed that relates to that thrust is a different variable. So all else being equal a four bladed prop would create more thrust at lower speed and the minimum speed to stay on plane would be lower

For the record, what is the source for the speed display? GPS data or pitot?

 

[Sardinia306Canyon]

So all else being equal a four bladed prop would create more thrust at lower speed and the minimum speed to stay on plane would be lower

For the record, what is the source for the speed display? GPS data or pitot?

Yep, i was surprised when reading that a GW (or any other planing hull boat) can plane at 6-7 knots.
Well it is possible having a overpowered boat who can turn high pitch 4 blades but that is very uncommon.
Chris

 

[family affair]

Speed is coming from the GPS.
To support seasick's point, the Eco Enertia prop lifts the entire hull reducing drag. That and the 2005 270 only has an 18⁰ dead rise.
The combination makes it easy to plane and gives really good economy. My only struggle is to get the props to hook up consistently in confused chop. Hopefully a little cup will fix that, but I need to go down 1 pitch.

 

[Ekea]

Too many variables to give a simple answer. In addition, do you want to know the speed stay on plane or the time to get on plane?

speed to stay on plane. how slow can you plane with tabs up? then how slow can you plane with tabs down?

 

[Ekea]

With a light load and no tabs 8-9 mph. Never tried with full tabs. Naturally I would expect anyone to call BS, so here is the photo:
View attachment 34757

Edit: Looks like I didn't have the engines tucked all the way in. I'll try to grab another photo next time out with engines all the way down.

wow, thats really impressive. i fall off plane around 20 mph with 3 blade props

 

[Sardinia306Canyon]

wow, thats really impressive. i fall off plane around 20 mph with 3 blade props

Yep, same with my Canyon and all other of mine or others boats i was on, planing speed was between 16 and 20 knots.
Slowest I could plane was my 30ft RIB at about 14 knots, but thats another hull and weight.

Chris

 

[family affair]

With the old f150s and SWS props, my minimum planing speed was similar to what you all are posting.
The port I frequent has an outer break wall speed limit of 10 mph. With the factory set up, I'd need to come off plane in the harbor, otherwise I was kicking up a huge wake and sucking gas. Now I can tuck the engines and stay on plane without the boat cops coming after me!

 

[GypsyRover]

With a light load and no tabs 8-9 mph. Never tried with full tabs. Naturally I would expect anyone to call BS, so here is the photo:
View attachment 34757

Edit: Looks like I didn't have the engines tucked all the way in. I'll try to grab another photo next time out with engines all the way down.

I had to do a double take on this pic; my Zukes had 93 hours yesterday!

 

[family affair]

I had to do a double take on this pic; my Zukes had 93 hours yesterday!

What engines and what props?

 

[GypsyRover]

What engines and what props?

I repowered last year with 200's 3 blade props, I'm not sure what the size is, I'm thinking 17 or 18?

 

[Halfhitch]

Naturally I would expect anyone to call BS

.....and you can count me on that list.

 

[seasick]

Speed is coming from the GPS.
To support seasick's point, the Eco Enertia prop lifts the entire hull reducing drag. That and the 2005 270 only has an 18⁰ dead rise.
The combination makes it easy to plane and gives really good economy. My only struggle is to get the props to hook up consistently in confused chop. Hopefully a little cup will fix that, but I need to go down 1 pitch.

Based on my readings, cup doesn't really help at low speeds ( actually revs). hmmmmm I think I should look that up again. I may be incorrect....

 

[family affair]

Based on my readings, cup doesn't really help at low speeds ( actually revs). hmmmmm I think I should look that up again. I may be incorrect....

I'm open to feedback. Coming out of the hole I can't trim up more than a ¼ without slip. I can't raise the bow much either. As stated before, certain chop conditions causes loss of traction up to about 30 mph. The prop gurus have advised to try cup and have been successful with other Zukes with Ecos having the same issue.

 

[seasick]

I'm open to feedback. Coming out of the hole I can't trim up more than a ¼ without slip. I can't raise the bow much either. As stated before, certain chop conditions causes loss of traction up to about 30 mph. The prop gurus have advised to try cup and have been successful with other Zukes with Ecos having the same issue.

Can you explain exactly what you mean by 'can't tri, up more than a 1/4 without slip"? Are you experiencing ventilation , blow out, or actual slip? If slip, how do you know that?
Is trim up referring to the motor or the trim tabs? Does trim up mean what I like to call trim OUT?

What model zukes do you have?
Sorry for all the questions. I am having a hard time understanding your issue

 

[Ekea]

engine trim up and trim out are the same. down and in are also the same

 

[family affair]

Can you explain exactly what you mean by 'can't tri, up more than a 1/4 without slip"? Are you experiencing ventilation , blow out, or actual slip? If slip, how do you know that?
Is trim up referring to the motor or the trim tabs? Does trim up mean what I like to call trim OUT?

What model zukes do you have?
Sorry for all the questions. I am having a hard time understanding your issue

Trimming the engines up/out - I can't go more than a ¼ up the scale without an issue. As far as what the prop is specifically doing, I don't know exactly other than I lose "traction." I don't know how to determine the difference between blow out and ventilation.
Df200 4 cylinders.