# Out with the old and in with the new IPB 16



## jttracey (May 3, 2011)

Picked up my new (to me) IPB 16 last night.

It will be replacing my 14' Stumpknocker that I've been fishing out of for the past 2.5 years.  Not sure if any of y'all remember it but here's a picture and some 'memory lane' pictures.



First fish in it:


Couple of successful trips:



Fed a lot of people!

First time getting towed back to the ramp:




Well I've been out of school in the real world for over a year now and have been keeping an eye out for a micro hull to suit my 70hp merc a little better than what it's currently on and finally found one.  Made the trip down to Corpus last night to pick her up.




Not a short trip, but certainly worth it.







I think she might be the prettiest thing I've ever seen. 
The back deck is hinged in the back with heavy duty latches in the front and a 12gal fuel tank bolted down beneath it. 
Not pictured that came with it - 
22' Graphite Push Pole (needs refinishing but beats the pants off my bamboo one I had)
Aluminum bow leaning rail/cooler frame (the guy had it made for his 105 qt yeti he used as a casting platform)

To do:
Move my Merc & TnT, battery, and trolling motor to the new skiff (trying to think of the quickest/most cost effective way to do this)
This will be my first time wiring up a boat from scratch but I'm looking forward to the learning experience. 
I will need binnacle controls for the new boat but I'm not exactly sure what I'm looking for.  I have just started researching my options but would love some advice.  I'd like some newer controls and I understand that I will need an adapter to make that happen but what else would I need? (1982/83 70hp Merc)

Also, if anyone in the Houston area is in the market for a Stumpknocker hull and trailer let me know!


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## TC (Feb 15, 2011)

Congrats on your skiff purchase! Are you sure it will handle your 70? I thought the IPB 16's were rated for 50hp max. (I had one. Power was a Yami 40 4-stroke. I believe the largest motors Eastcape was putting on them were Honda 50's.)

Maybe you know something I don't.


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## jttracey (May 3, 2011)

Thank you sir! 

No, you are correct they are rated for 50hp.
I think the weight should be fine for the time being though since those 70 mercs only weigh in at around 190lbs.

I am currently looking around for a 40 or 50.
Just need to sell my old rig for some more $$$$$ ;D


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## jttracey (May 3, 2011)

So I'm kicking my stupid self this morning because I realized that I never took into account the change in transom height...
I know I have a jackplate, but I don't think that it will compensate enough to bring the cavitation plate flush with the bottom of the transom.

My 70 is a longshaft (20") and the IPB transom is 15"

Since this realization I've been running through all my possible options but would like to hear from y'all.

1. Is it possible to still use my outboard? I've done a good bit of googling on this subject and it does seem possible via one of these guys:
http://www.thmarine.com/products/Outboard-Jack-Plates/Static-Height-Plates/CMC-Static-Jack-Plate-5-inch-vertical-extension

But would it be safe? And also, would it be possible to mount my cmc TnT on since my Merc does not have TnT?

2. Sell the whole rig and start looking for a short shaft.

So far, those are the only 2 avenues that I seem to have...


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## Dillusion (May 21, 2012)

Why dont you call brad? He sells a metal riser plate made out of 1/2" stainless steel plate that brings the transom up to proper height.


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## firecat1981 (Nov 27, 2007)

Sell the motor, and buy a short shaft. Using a riser plate is ok at best, but only in the HP range. Over powering and using a riser will add tons of torque to the transom and can lead to failure.


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## Dillusion (May 21, 2012)

> Sell the motor, and buy a short shaft. Using a riser plate is ok at best, but only in the HP range. Over powering and using a riser will add tons of torque to the transom and can lead to failure.


You will be hard pressed to find a 'short shaft' 50-70HP motor. Even mercury only made a short shaft into 40-50hp with their two-strokes. Yamaha/Merc 2-stroke 70HP were all long shaft 20" motors.


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## firecat1981 (Nov 27, 2007)

> No, you are correct they are rated for 50hp.
> I think the weight should be fine for the time being though since those 70 mercs only weigh in at around 190lbs.
> 
> I am currently looking around for a 40 or 50.


Sell the 70hp, and buy a nice 50hp short shaft with TnT.


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## jttracey (May 3, 2011)

> > Sell the motor, and buy a short shaft. Using a riser plate is ok at best, but only in the HP range. Over powering and using a riser will add tons of torque to the transom and can lead to failure.
> 
> 
> You will be hard pressed to find a 'short shaft' 50-70HP motor. Even mercury only made a short shaft into 40-50hp with their two-strokes. Yamaha/Merc 2-stroke 70HP were all long shaft 20" motors.


I don't exactly recall the date that Merc stopped rating hp at the crank, but wasn't it after '85?  Wouldn't that mean that if my 70hp was rated at the prop it would be closer to 45-50hp?


Yeah I know they're out there but few and far between.

Thanks for the help so far guys!


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## firecat1981 (Nov 27, 2007)

I think most outboards have been rated at the props since '84, if memory serves me. However I have heard merc used to test at the prop even before then which is why they were always thought to be under rated back in the day. Even assuming a 20% loss in efficiency you are still at 56hp, but I'm betting it's better then that.

What year is the Merc?


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## jttracey (May 3, 2011)

> Why dont you call brad? He sells a metal riser plate made out of 1/2" stainless steel plate that brings the transom up to proper height.


Tried calling him but his mailbox is full.


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## jttracey (May 3, 2011)

> I think most outboards have been rated at the props since '84, if memory serves me. However I have heard merc used to test at the prop even before then which is why they were always thought to be under rated back in the day. Even assuming a 20% loss in efficiency you are still at 56hp, but I'm betting it's better then that.
> 
> What year is the Merc?


I think it's between '80-'83.  I'm still trying to track down the serial number on it but that's another discussion all together.  I've looked at A LOT of pictures/videos and read everything I've been able to find about these motors and my best guess is that year range.



I'm also taking into account that she is 30 yrs old and has probably lost a step or two since she came off the production line.


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## Gramps (Nov 1, 2007)

JJ - Don't you have the registration for the motor? :-X

I would text or email Brad - sometimes seems the easiest to get a hold of him. But like the others have said, I would not want to hang that motor until you get the green light from IPB.


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## jttracey (May 3, 2011)

Gramps-
The motor was purchased in Tennessee where they do not require any registration or titling for outboards.  I have spoken with TPWD and I just have to present my Bill of Sale and a letter from the seller stating that the motor was included in the purchase price.  I'm going to have to take it to a dealer though to see if they can find the welch plug that has the serial # stamped into it.


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## jttracey (May 3, 2011)

Update:
I actually found a guy that's decently local that is wanting to trade his 1990 Mariner 40hp Magnum for my Merc.  Currently trying to work out details of the trade.

Does anyone have experience with these motors?  Serial # OC168568.
He'll be sending me a video this evening, but here are some pictures:







Seems like a great deal and more or less perfect for the IPB.

edit: except that it isn't a short shaft...


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## Gramps (Nov 1, 2007)

4 cylinder 40?   That bad boy may be too heavy! 


Hrmmm google fu says 187lbs so that may be a great engine choice!


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## menzor29 (May 23, 2012)

I went through the exact same thing as you JJ, I had a 81 stumpnocker with a 20in, 25hp mariner on it that I ran for a while then decided to try and strip and rebuild but just ended up buying a IPB16. I thought if I got a jack plate i could get away with it but just couldn't get the damn thing high enough. it wouldn't plane right and the drag was unbelievable. your definitely doing the right thing if your going short shaft. with some patients I found a 40rude, short shaft, tiller everything i needed for a good deal. with the jack plate dialed in the thing will scoot pretty good.


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## jttracey (May 3, 2011)

SoCo - Wow we did go through nearly the exact same series of events 

A short shaft would be ideal but it's not in the cards just yet (and by cards I mean budget ;D )
I ordered a set of CMC 5" Vertical Adapters from to raise it up to the proper height so hopefully those paired with the jack plate or my TnT will ensure proper alignment. Has anybody here done this?
Right now I'm just trying to get it rigged up and on the water as soon as possible!

The outboard trade is still in the works. After much deliberation I have decided that if the trade does not go through I will be mounting my 70 on the back. I figure it weighs less than most newer 50hp motors and the extra power won't be dangerous if used safely and responsibly. I'm speaking strictly from reasoning based on physics and not legality or liability.

I'm going to try and install the casting platform leaning rail this afternoon/evening if I can get off work in time to stop by home depot.
Will post pictures hopefully this evening.


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## menzor29 (May 23, 2012)

Dude as long as your getting that motor high enough it should run might look funny (idk because never seen it) but it will definitely run. Only thing is, just sitting here brain storming, is whether the torque being way above the top of the transom like that would add in adverse affect to the transom. just to add, some long shafts are longer than others..lol, my mariner was like 22" I have seen some at like 19." or 19.5" or just 20" depends on brand i guess.


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## jttracey (May 3, 2011)

This was/is my primary concern. 
I've been doing some research on torque and here are the numbers I've come up with. They're not exact but they get the idea across.

1983 Mercury 70hp (190lbs) -
(Assuming max rpm of 5,800 & 2:1 gear reduction ratio)
67 foot-pounds of engine torque
122 foot-pounds of propeller torque assuming a propeller RPM of 2,900 (If someone knows the actual gear reduction ratio that would be awesome)

Brand New Mercury 50hp 4cylinder (260lbs) - 
43 foot-pounds of engine torque
98.9 foot-pounds of propeller torque with calculated propeller rpm of 2,575 (6,000rpm/2.33:1 gear reduction)

1989 Mariner 40hp Magnum 4cylinder (187lbs) -
38 foot-pounds of engine torque
76.6 foot-pounds of propeller torque

Is it a generally accepted principle that the propeller will produce torque approximately equal to twice the engine's horsepower? 
Also, I have not yet found an equation that allows me to include the variable of increased engine height. After the height is added, how much effective torque will be added to the transom after factoring in the coupling of the hull and outboard? 

Also, does the engine weight have any gravity beyond increased/decreased displacement?

After these calculations my concern has returned...damn...


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## jttracey (May 3, 2011)

Well, I went through with the motor trade and got everything just about rigged up. Only hitch in the trade was the tilt and trim on the motor doesn't work (no problem since I haven't sold the CMC TnT on my old skiff yet).
Went ahead and ran it all over Clear Lake on Saturday and Sunday with out the TnT just because I was itching to get out on the water. 
It ran very well but with the motor tucked under the whole time anything past 3/4 throttle and the bow would get shoved down into the chop (made for a very wet ride)
Getting the TnT rigged up this week. Hopefully I'll have it done by the weekend.

Found binnacle controls, cables, key switch, and kill switch all for a little under $250. 

I haven't been very good with recording the process visually but I'll post some pictures and a vid after I get the TnT rigged up.


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## 'Nano-Skiff' (Aug 27, 2012)

Yes more pics please!


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## cor21e (May 4, 2011)

so Your saying a short shaft is 15 inches long right? and a long shaft is 20"



> I went through the exact same thing as you JJ, I had a 81 stumpnocker with a 20in, 25hp mariner on it that I ran for a while then decided to try and strip and rebuild but just ended up buying a IPB16. I thought if I got a jack plate i could get away with it but just couldn't get the damn thing high enough. it wouldn't plane right and the drag was unbelievable. your definitely doing the right thing if your going short shaft. with some patients I found a 40rude, short shaft, tiller everything i needed for a good deal. with the jack plate dialed in the thing will scoot pretty good.


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## menzor29 (May 23, 2012)

I thought for second maybe this is some type of trick question, then i thought hmmmm maybe this dude is being an ass then i remembered i have asked a few memorable ones myself... yes i do believe the general guideline is short shaft 15in and long shaft 20in. 



> so Your saying a short shaft is 15 inches long right? and a long shaft is 20"
> 
> 
> 
> > I went through the exact same thing as you JJ, I had a 81 stumpnocker with a 20in, 25hp mariner on it that I ran for a while then decided to try and strip and rebuild but just ended up buying a IPB16. I thought if I got a jack plate i could get away with it but just couldn't get the damn thing high enough. it wouldn't plane right and the drag was unbelievable. your definitely doing the right thing if your going short shaft. with some patients I found a 40rude, short shaft, tiller everything i needed for a good deal. with the jack plate dialed in the thing will scoot pretty good.


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## Gramps (Nov 1, 2007)

The definition of short shaft vs. long depends on the manufacturer and horsepower. Generally speaking, for the Microskiff mindset, 15" is short and 20" is long. Get into HP much 40 and over, it seems that 20" becomes the short and/or standard shaft length.


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## jttracey (May 3, 2011)

Snapped some quick pictures of it rigged up today






The bottom of my 5in extension plates need to get trimmed off I think...
They don't extend under the bottom of the hull so I don't know how they'll effect the water pressure while underway. What do y'all think?


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## jttracey (May 3, 2011)

Also, is it possible to clean my old TnT to return the shine?


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## makin moves (Mar 20, 2010)

mothers polish


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## Gramps (Nov 1, 2007)

Looking good JJ! Regarding the extensions - trim them, they are lower than the cav. plate and will cause drag. As MM mentioned, Mothers with a powerball type thingy-ma-jigger will bring back the shine.


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## Dillusion (May 21, 2012)

You put a jack plate on a jack plate? Holy cow.


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## rkmurphy (Nov 2, 2008)

that thing has more setback than the US Economy

Bet you can raise that motor up a good bit, though. Let us know how it performs. Looking good!


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## shadowcast98 (Jun 21, 2013)

Love that side console! ;D


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## jttracey (May 3, 2011)

Matty - *an extension plate on a TnT... but yes...yes I did...
I actually had those mounted on a static jackplate last weekend and it ran great.

Ideally I would have just bought a new shortshaft motor but that's not going to be happening anytime soon. 

murph - I'll try and record a video this weekend to post up

justakid - thank you sir. i think i might look into changing it to a CC at some point down the road but I love the current set up.


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## oysterbreath (Jan 13, 2009)

HA! You've got the same motor as me!
40hp, 4cly, 2 stroke.
Mine is the Merc branded version.
I here that these motors are smoother than the 3cly 2 strokes.








Did you have to do much work to it? My T&T wires are bare, I have to prolly replace the whole pump though. I'm not sure yet. I haven't run it since it was bought MONTHS ago.


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## jttracey (May 3, 2011)

According to my serial # mine is Merc built as well. 
What year is yours?

Wiring the CMC TnT to the motor's TnT harness was pretty straight forward and looks a lot cleaner than using the relay setup I had on my old skiff. 
I can try and send some pictures if you're considering the same rigging.
I didn't really even consider replacing the motor's pump as I already had the CMC TnT. 

I hit the water yesterday for a couple of hours yesterday. 
After I was done fishing I ran it around for awhile testing out the TnT and getting more comfortable with it. It made a HUGE difference!
Those extension plates definitely need to be trimmed up though.


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## jttracey (May 3, 2011)

Also, I'm wondering where I should mount my lowrance elite 5 on my console.  Ideally, the RAM mount would be where the tach is mounted and the tach would be moved down about 6 or 7 inches.  Buuuuttttt I don't want to do all the glass work.  

So I'm thinking the RAM base will be going directly to the left of the tach so that the lowrance can be angled out (to stay out of the way of the wheel and throttle).  I also considered mounting the base to either the vertical surface on the front or side of the console but don't think that would look as clean.

Any other ideas on a clean mounting solution?  



I thought I remembered seeing a small console picture thread somewhere on here but can't seem to track it down.


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## rashouri87 (Jul 2, 2009)

IMHO I think you lost a lot of performance going the way you did. On my IPB we run a 15" shaft tohatsu tiller on a minijacker hydraulic with a powertech stainless prop. You would be shocked at how high we can jack it before it cavitates in turns or blows out. That's ideal for our area since we don't have to worry about scarring up grass flats and the creeks often have sneaker sandbars. The added benefit of fuel economy is nice too. The best part is at idle though, we can jack it all the way up and then trim it to idle in the shallowest of conditions its nice for getting to the very back of creeks etc.


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## jttracey (May 3, 2011)

Rum - There is no question at all that this isn't the ideal set up.
But the kicker is, it didn't cost me a dime. 

Finally got my Ram mount for my GPS/FF 
Just deciding where to mount it up now. 



Never owned a decent unit like this but I'm thinking that this first option would be best for ease of access/viewing.


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## Recidivists (May 9, 2011)

What about the front right side of the console? Not the top, but the front side.


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## Dillusion (May 21, 2012)

Change out that gigantic steering wheel made for a barge or cruise ship. Get a normal sized one.

Step two is to mount the GPS like you did in photo 2. That's the only logical option aside from mounting it on the front side face of the console like recid said above.

I would never mount anything that obstructs your range of motion on your throttle.


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## AfterHours2 (Aug 2, 2010)

Thats a huuuuuuuuuuuuge Beatch! Steering wheel that is ;D


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## jttracey (May 3, 2011)

recid - I considered that option but wanted to avoid it if at all possible.

matty - I actually had not considered a smaller steering wheel but now that you mention it, it is a little ridiculous.  Would 11" be too small or just go down to a 13"?

I'll go with the second option and change out the steering wheel.


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## Dillusion (May 21, 2012)

> recid - I considered that option but wanted to avoid it if at all possible.
> 
> matty - I actually had not considered a smaller steering wheel but now that you mention it, it is a little ridiculous.  Would 11" be too small or just go down to a 13"?
> 
> I'll go with the second option and change out the steering wheel.


Now if I could only convince you to remove one of those jack plates and relocate your gas tank to the bow, you would have a really nice skiff.


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## jttracey (May 3, 2011)

Is there another option I missed to get a 20" motor on a 15" transom?
It's not that I don't want to do these things. More so that it will take some time for the $$$ to catch up with the wants.

Also, any opinion on the wheel size?
It seems like the smaller the better to accommodate the FF/GPS but 11" seems awfully small for some reason.


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## BayStYat (Sep 12, 2012)

13" wheel size is perfect.  That looks like a 15" 

2" less is a big difference 

As for the daaaaable jack plate deal, just call Brad and get the riser plate he makes for 20" motors on his transom. 

Nice ride


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