Ran the Dink

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Re: Ran the Dink

Postby bobvdinghyracer » Wed May 02, 2018 12:00 am

chine walk ??? been down this road myself .... prop not made to do what you are trying to attempt ... it `s raised up WAY too high ... drop the motor
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Re: Ran the Dink

Postby Fastjeff » Wed May 02, 2018 12:39 am

...."Are you planning on just making small changes or new design."

Really small changes. The inner strakes have always been minuscule compared to other fast boats, so I'm going to increase the size of the inner strakes. Hopefully that will dampen the chine walk.  Also, to get back the stern flotation it had before, the "notch" will be filled in (so to speak). The deepened pad will remain UNLESS the chine walking isn't cured.  (See retouched photo.) If that's the case, the deepened pad will go as well.  

That's my plan and I'm sticking to it!

Jeff

PS to Dingy Bob: Only running 2 1/2 inch cav plate height, which translated into a minuscule 1 or so with the notch. Hardly way up there!
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Re: Ran the Dink

Postby daveswaves » Wed May 02, 2018 1:16 am

We triedto get him to drop the lower unit deeper.   :?:
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Re: Ran the Dink

Postby 1500J » Wed May 02, 2018 2:05 am

https://youtu.be/VO5SYmZ0A_M   5-1-18 video

Boat looks good.  You need more prop.  

What is your speed on these runs?   RPM?  Need these details.

Conrad
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Re: Ran the Dink

Postby Yellowjacket » Wed May 02, 2018 3:54 am

You've got the correct trim angle, if you fill the notch you're going to push the bow down and that will get you back where you started.  

Moving the CG aft 6 inches relative to the pad is what is getting the bow up, and getting the bow up increases the trim angle and the boat actually runs shallower.  For instance, with 22 inches of width in the water and the CG at 1.8 feet from the trailing edge gives you a trim angle of 3.9 degrees and at 42 mph a depth of 2.1 inches, and it takes 25.7 hp to get there.  With the CG at 2.4 feet (the setup with no notch), to go the same 42 mph, you need 28.2 hp, the running depth is 2.6 inches, and the trim angle is 3.2 degrees.   With a 10.5 inch pad the depth goes up and the power required is over 35 and the depth is over 4 inches, so it isn't running on the pad alone.

As it is currently running, the depth is enough for the hull to be running somewhere between the pad and the strake, with the strake still providing a good bit of lift from the redirection of spray.

Since the strakes are not fully immersed, changing them by making them wider won't do anything, all they are doing is breaking the spray to get it off the hull.

To get actually up on a pad that narrow would take a lot more speed.

I think you need a more efficient prop, and that will get you going faster.  Right now the prop efficiency is in the toilet...  You've got to get that sorted out and you'll go a lot faster and with speed the chine walking should be reduced.

I don't thing that running really shallow is necessary, you've got lots of power relative to what it takes to drive the hull, the issue is prop efficiency.

Also, with a cable steering system and a padded hull you don't want springs in the steering system, you need to have a very stiff steering system and a Teleflex system is probably a better idea, but cables can work if they're tight and don't have any springs in there to let it flex.
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Re: Ran the Dink

Postby Fastjeff » Wed May 02, 2018 12:29 pm

..."As it is currently running, the depth is enough for the hull to be running somewhere between the pad and the strake, with the strake still providing a good bit of lift from the redirection of spray."

Okay, but won't the wider strakes dampen that damn chine walking?  Look at the Hydro Stream XT-1 (below).  The sole purpose of those ‘sponsors’ was to kill the chine walking.  I built a hull (Hull # 2 of the original 9 footer) to eliminate that and it did, but the boat was slow, nasty in a chop, and surprisingly hard planning off—but it never chine walked.

…”Since the strakes are not fully immersed, changing them by making them wider won't do anything, all they are doing is breaking the spray to get it off the hull.”

Okay, but goal number one is to make the boat safe.  The SOB nearly killed me again yesterday (as you can see as it leaves the shot).  I’m even willing to write off my 50 mph goal to eliminate that. Safety first.  (It rarely did that before lowering the pad, incidentally, and top speeds were about the same.)

Goal number two is to keep the stern from dropping into a hole like it does and flooding the motor.  Granted, I can climb over the dash and ease her back down, but what if I'm out there in a chop and have to  drop off in hurry, with a big wake approaching?  Might loose the boat!  So the notch has to go, regardless of what it does to performance.

…”I think you need a more efficient prop, and that will get you going faster.  Right now the prop efficiency is in the toilet...  You've got to get that sorted out and you'll go a lot faster and with speed the chine walking should be reduced.”

Agreed.  (Grumble, grumble...) My problem is that I haven’t the funds to buy several props before stumbling onto what I need: a 3 blade 10 x 17. or a 10 x 18, or a….$$$ experimentation.

…”Teleflex system is probably a better idea.”

That’s what I have and there’s minimal slack in the system.

Thanks again for all the work you did!

Jeff

PS: I'm intending to send my buddy Ron Hill a request for a 10 by 17 to 19 pitch SS chopper and see what he can do for me.
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Re: Ran the Dink

Postby Fastjeff » Wed May 02, 2018 1:09 pm

..."with 22 inches of width in the water and the CG at 1.8 feet from the trailing edge gives you a trim angle of 3.9 degrees and at 42 mph a depth of 2.1 inches, and it takes 25.7 hp to get there.  With the CG at 2.4 feet (the setup with no notch), to go the same 42 mph, you need 28.2 hp, the running depth is 2.6 inches, and the trim angle is 3.2 degrees.   With a 10.5 inch pad the depth goes up and the power required is over 35 and the depth is over 4 inches, so it isn't running on the pad alone."

Here's where the above lines up with the hull.  It appears to me, looking over my shoulder (and loosing another hat!) that at least 4 inches of hull depth remains in the water.  If so, the larger strakes would HAVE to do something.

Jeff

PS: This photo is not a high riding hull--it's a port side chine walk.

download/file.php?id=24813&mode=view
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Depth of Running.JPG
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Re: Ran the Dink

Postby Yellowjacket » Wed May 02, 2018 1:42 pm

Have you looked a props that have a removable/replaceable hub, and can you get an inner hub that will fit your shaft spline...

Maybe by mixing and matching pieces parts you could get what you need that way.

Just thinking out loud...
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Re: Ran the Dink

Postby Yellowjacket » Wed May 02, 2018 1:48 pm

What is likely happening is that as you slow down the effective cg is further aft of the end of the planing surface and that results in more pitch up moment so as you come off a plane the nose is pitching up more and the trailing wave is catching up with you and getting close to swamping.

Add surface aft, but outside of the inner strakes and the nose won't pitch up so much at low speeds.

At high speed all of that is out of the water...  If need be you could add some floatation back there too to keep the motor higher when it is just sitting still.
Last edited by Yellowjacket on Wed May 02, 2018 1:55 pm, edited 1 time in total.
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Re: Ran the Dink

Postby 1500J » Wed May 02, 2018 1:53 pm

What was your speed and RPM? During this run? Thanks

Are you in the 40 mph area during this?  

What is your speed on these runs?   RPM?  Need these details
 ME

And again, are you recording MPH and RPM?  

If you posted it I am sorry I missed it.  Each run should have a basic report. including MPH RPM.  Without that we are shooting in the dark.
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Re: Ran the Dink

Postby 1500J » Wed May 02, 2018 2:07 pm

Analogy Time!

:arrow: This whole thing reminds me of the fat bride trying on dresses.  She keeps trying different dresses on over and over and never happy because they all make her look fat.   All the while her bridesmaids scurry about  giving her heaps of technical details on how to stand and walk to help minimize the width of her beam.   The end of the day the bride throws all the dresses away that made her look fat never accepting what needed to be done.  :arrow:


In the above story the bride probably needed a better health plan and some exercise, changing dresses did nothing.   In your story you need a better prop/steering and some practice.

C
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Re: Ran the Dink

Postby 1500J » Wed May 02, 2018 2:58 pm

Now ,

Have you ever considered using your trim tabs as training wheels?    Trim the motor up to where you should be and keep the trim tabs down.     Slowly raise the trim tabs to increase speed.
At some point they should just just be out of the water at WOT, but very close to catch you when you start to wobble side to side.


The faster you go the easier it is to balance on a pad.  In some V bottoms that were sketchy I just had to push past the unstable speed to get to where the boat was more supported by air and the faster the water is going under the pad the harder the water is.  The water turns closer to concrete and easier to balance on.

I dont think your prop has enough pitch or bite to get you to the next level.   I dont know for suretho since I dont see RPM posted.

For what you have in your hands right now, I think it looks very good to be honest.  If you want to take the next step its not likely going to come with chopping the boat up anymore.  Stay safe.

C
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Re: Ran the Dink

Postby Fastjeff » Wed May 02, 2018 6:58 pm

Sorry for delayed response--the wife has me out camping again. (Ugh!)

Speeds (depending on the prop used) are from 35 to 40  mph or so.  It might go faster if I could hold her wide nopen longer, but I can't--don't want to barrel roll!  Rpm are 5,500 to 6,000, again depending on the prop.

Love to play with the trim tabs and motor trim, but... (See above.)

First things first: Cure the chine walking.  Then stop the "U-boat" action when coming off plane.  Then...

Thanks for nyour inputs,

Jeff

PS: Hottest day of the year and we're camping!
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Re: Ran the Dink

Postby 1500J » Wed May 02, 2018 8:23 pm

Fastjeff wrote:Sorry for delayed response--the wife has me out camping again. (Ugh!)

Speeds (depending on the prop used) are from 35 to 40  mph or so.  It might go faster if I could hold her wide nopen longer, but I can't--don't want to barrel roll!  Rpm are 5,500 to 6,000, again depending on the prop.

Love to play with the trim tabs and motor trim, but... (See above.)

First things first: Cure the chine walking.  Then stop the "U-boat" action when coming off plane.  Then...

Thanks for nyour inputs,

Jeff

PS: Hottest day of the year and we're camping!



Obviously one prop is running 40 and the other 35.  How about we stick with the fastest one and work in a positive direction from there.

How about what RPM is the fastest prop turning?

Your data is really loose.

Get off the computer and enjoy camping.  Have a good one.
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Re: Ran the Dink

Postby zul8tr » Wed May 02, 2018 9:25 pm

Some V's in action, a lofty goal with the dink. Note there both going down hill  :wink:
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Re: Ran the Dink

Postby Fastjeff » Sat May 05, 2018 7:41 pm

Amazing to me is how far forward the drivers sit in each boat--I'm practically sitting on the transom, yet their boats ride nice and bow high as well.  I say "as well" 'cause, after looking at years' worth of in-boat video, and comparing the horizon to the bow, it seems like the bow was always coming up.  (Yeah; I'm embarrassed!)  

The drive by video was a revelation! Got the idea after I watched Conrad's old Dock Wrecker video over the winter with the camera on a dock  (or was it a break water?)  That gave me the idea of putting the camera on....something.  More thought and I recalled there's a duck blind right there in the river.  Halleluiah!

Hull Number 4 is mostly done.  Needs another coat of paint and the aluminum hull protectors have to go back on.  Hope to splash early in the week.  It features wider, deeper strakes (the old ones were a joke), removal of the deeper pad (before it killed me), and the elimination of the notch (before I swamped dropping off plane).

Jeff
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Re: Ran the Dink

Postby 1500J » Fri May 11, 2018 11:31 pm

Is this thred  dead now?  

Sounds like in another thred your changing powerheads again?   You started with a Mark 78, then to stock triple , then maybe a modified triple, now possibly back to a stock triple.   Is that whats going on now?  

Im lost.

Time for a beer.  [drinkingcheers.gif]
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Re: Ran the Dink

Postby Fastjeff » Sat May 12, 2018 2:23 am

Yeah.  The external reeds motor won't idle down for some reason without 'dive bombing' to a stop.  Had this problem before and cured it, but I don't remember how I did it.  (So much for my meticulous record keeping!)  Shame, for it would have pushed the boat at least 5 to 7 mph faster--maybe more.  

Got too much on the old plate right now to mess around with it--I'll tear it down and find out what's going wrong in there later this summer.  The Mark 78 is waiting in the wings should that reliable stock triple George got for me fail.

Jeff
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Re: Ran the Dink

Postby 1500J » Sat May 12, 2018 5:11 am

Ok  hope it works out for you.   [fingerscrossed.gif]

Im gonna step away from this .  [drinkingbeer.gif]

Ill leave you with some final thoughts.  Most I've told you many times before.  [drinkingbeer.gif]

You need to blow the dust off that wallet and buy a  performance propeller to go faster, if you decide to try again.     When you go faster your going to need at least dual cable steering to control the speed your new prop is going to go.     As your balancing your rig at 50-60 MPH you don't want to be pumping a bottle jack for trim, because its dangerous, and it just plain looks funny from the shore as you go by pumping away.  :D

Until the above is figured out, enjoy what you have as is.   No sense pushing a rig not set up right and getting hurt.
Stay safe. Conrad
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Re: Ran the Dink

Postby Fastjeff » Sat May 12, 2018 10:44 am

Thanks, buddy.  Totally agree.

It was fun getting the boat to go faster, but I'm not enjoying boating like I used to. Haven't even gone a mile from the ramp yet--too busy making test runs.  Enough!

Jeff
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