Stinger Placement in a Mono

[rickwess]

I've just spent the last 30mins using the search tool and came up empty. The info might be somewhere, but the typical thread tittle doesn't help the search.

My question is where on the transom to mount the stinger? How far up from the keel? I think I've read a long time ago that about 3mm between the keel to the bottom of the stinger housing/bracket. Does that sound right?

Then there there is the question of offset or not. Thoughts?

Thanks for your help.

[ray schrauwen]

Forget the offset Rick, just get the height correct. Do you have a Speedmaster or Chinese Stinger because Speedmaster has a little bit of adjustment if you build a wet well for it first. I can explain a simple wet well design too like I did on my 40" mono if need be.

[rickwess]

Speedmaster from OSE

[rickwess]

........so what is the correct height?

[TheShaughnessy]

http://www.insaneboats.com/wp-content/uploads/2010/12/Insane-mono-set-up.doc

That's for their gas monos, not sure it would be the same for FE. 3/8 - 1/2 " should work well.

[iop65]

unless you have figured out how to defeat mister Newton's laws of physics ,more exact his third law (action-reaction) i would go for offset!

[Fluid]

While it used to be de rigeur to offset the strut on a mono, it is now pretty much accepted (among many winning racers anyway) that the strut should be centered above the keel. But the height above the keep depends an the hull and the speed. It will be different on a deep vee versus a shallow vee, and different on a 26" hull versus a 38" hull. 1/2" from the bottom of the strut to the keel on a DF26 will not work very well.

There is NO universal best height. Too low and the boat chine walks. Too high and it runs wet. Only with some adjustment does the modern boat tuner get an optimally handling mono.



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[rickwess]

While it used to be de rigeur to offset the strut on a mono, it is now pretty much accepted (among many winning racers anyway) that the strut should be centered above the keel. But the height above the keep depends an the hull and the speed. It will be different on a deep vee versus a shallow vee, and different on a 26" hull versus a 38" hull. 1/2" from the bottom of the strut to the keel on a DF26 will not work very well.

There is NO universal best height. Too low and the boat chine walks. Too high and it runs wet. Only with some adjustment does the modern boat tuner get an optimally handling mono..

I read the .pdf that Michael liked to and the 1/2" was from the keel to the centre of the stuffing tube hole, not to the bottom of the stinger Of course that guideline will all depend on the dimensions of the stinger.

To find a starting point I need to find someone who has set-up a SpeedMaster stinger on a Insame Mono 34. Where is Tony?

[properchopper]

I set them at 3/8" from bottom of keel to centerline of shaft. No offset.

[rickwess]

I set them at 3/8" from bottom of keel to centerline of shaft. No offset.

Thanks!

[iop65]

racing boats i know (mono1-2-3)have different set-up :the balance is totaly different from sportboats (floodchamber ,all lipo's on the left,even some extra weight to to left to make it turn faster after a flip ...and so different weight balance in the lenght axle
this makes the boat handle differently:almost all the weight is on the left side

and i can imagine that in racing, with only right hand turns, it could evenbe an advantage making the boat pulling slightly to the right

but for me ,a sport boater, i like it to be offset: less steering input and thus draft to get it straight

as i wrote before :i'm not a "stingerfan" :you can not adjust the angle without changing the dept of the prop

[properchopper]

i can imagine that in racing, with only right hand turns, it can be even an advantage to put the shaft in the center and making the boat pulling slightly to the right

but for me ,a sport boater, i like it to be offset: less steering input and thus draft to get it straight

as i wrote before :i'm not a "stingerfan" :you can not adjust the angle without changing the dept of the prop

I must respectfully beg to differ with both of your points.

#1] I've built several IB34's and my club alone has five including mine which I race regularly. No one has reported that the boat "pulls". Sounds great in theory but not in reality. Plus when you offset the driveline, compromises must be made in the driveline alignment- not the best idea.

#2] If you use a strut instead of a stinger, changes in strut angle will likewise change prop depth. If you use a strut AND a wet well flooded tube to allow angle changes minus depth alteration by raising or lowering the strut to compensate, it also will make height changes available with a stinger since the stinger mount is slotted to allow up/down adjustments as well.

DSC05145.JPG

Vertical shaft height adjustment in monohulls, whether with a conventional strut or a stinger, must be accompanied by a flood tube. Since, as I've pictured, the Spd strut has slotted mounts, I just don't understand why I see so many posts that claim that stingers can't accomplish this.

[Greg Schweers]

It's all going to depend on what motor combination you run in this boat. If you're going to run props that are 50 mm and bigger, 3/8" is probably pretty close. You'll know right away if it's too high - if going down the straight you give it left and right and it blows air, it's too high. Also, the Insane 34 likes rectangle turn fins. When I built my 34 I ran a 1527 half Y and a 27 1D; I was running a 447 prop. I had my stinger at 1/4". I noticed you foamed the front part of this boat; every mono I've had does not like weight forward, and I'm sure that foam added over 4 oz. You may end up with a boat that nose steers. Everybody thinks that when the water gets rough, they should move the cg forward. What you should do is put weight on the cg. Once you move the weight forward, and the boat leaves the water, it's going to come down nose first.

[rickwess]

The motor is a TP4060 2040kv.
Prop is a x447/3 or x450/3. I also have a m445 and m545 but I'm sure they are too small.

Yes I did foam the bow. 4.69oz to be exact. Not much more weight though, if any, than stuffing pool noodles into the bow.

I knew the location of the hole was critical, hence me asking.

[iop65]

i like a good discusion Tony ,no problem,it's a change to learn from eachother!

i agree that with that flood tube it's possible to accomplish the change in angle without changing the dept for that stinger , but i hardly see someone doing it over here

obout the off-set :we are talking about 1 to 2 mm
and as you know there are many ways to countereffect or minimize the prop-walk effect ,i can believe that if you get all the rest perfect(prop/position rudder/position turn-fin...) (like a guy like you can) can make those effects to a minimum, but they always will exist

i put always a little offset in ,it's physics for me ,and not only theory

like someone wrote yesterday :someone got to do what he likes and works for him


ps : i live in europe so i appologize for my not so perfect english