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Building a 7'6" Crackerbox

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Building a 7'6" Crackerbox

Old 02-17-2008, 09:53 PM
  #76  
2005ARSENEAU
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Default RE: Building a 7'6" Crackerbox

A few more...
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Old 02-17-2008, 11:41 PM
  #77  
c-cat
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Default RE: Building a 7'6" Crackerbox

Cool boat! I like the modified outboard concept, might have to have a stubshaft coupling made to connect the powerhead to the lower unit. I might have to 1/4 scale an offshore cat and mod my old 18hp merc! Sweet ride keep up the on the info, way sweet!
Old 02-17-2008, 11:51 PM
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stuch
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Default RE: Building a 7'6" Crackerbox

ORIGINAL: 2005ARSENEAU

A few more...
guy i think 2 polini clone motors will move that boat just right. i have real polini race motors in my pocket bikes there 50 cc and 12hp motors and one of my grc p/b's is 60lbs and i weight 187lbs and it gps's at 47mph and pulls the front wheel up at will. and i also have polini clone motors in other p/b's with running weight of 60lbs also and the clone motors dynoed at 10.3 hp and those bikes gps at 44mph. the blata clones are 39cc with 7hp but on e-bay theres a 50cc jug for the motor with some case modding they run strong. all my motors have 19mm delorto carbs. the polini clone comes with a 18.5mm del carb and the blata clone comes 14.5 del carb. the polini clone motors are bullet proof motors. all you have to do is set the squish to .50mm and polini green reeds in the reed cage and the 19mm del carb. and i think the boat will move pretty good. go to this site PocketBikePlanet.com join the site and post what you're doing on you're project and myself and other members will give you more info and a link where you can buy and how to mod these motors. to purr like kittens. also if you want to do a search on the site to see info on the polini based motors look up banshee p/b's if you want to see info on blata clone motors look up c1 or the new bike with the blata motor c2 p/b's. if you do post a new thread there post in the water cooled section that where the real turners are. also on the left of the site you'll see p/b parts for sale. guys are always selling these type of motors. i have a polini 50cc clone motor with like 5 breakin runs on it runs strong and it rev'd to 15,100rpm's with me on it. its currently for sale pm me for more info and pictures.
Old 02-18-2008, 09:42 AM
  #79  
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Default RE: Building a 7'6" Crackerbox

http://www.northerntool.com/webapp/w..._278476_278476
Old 02-18-2008, 12:24 PM
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Default RE: Building a 7'6" Crackerbox



2005.

I have a 8' WW II Higgins PTB. It weighs 45# with no ballest. 90# at MINIUM water line.
I first put in a HUGE 55 cc chainsaw engine with a 1 ; 1 timing belt overdrive. It had to drive 2......5" x 5" x 5 bladed props. Engine was used / abused ?
Bottom line was it could not get up on plane.
Switched to a 16# Minnkota motor. Still a ploughing tugboat.

Put in a new 41# thrust Minkota. Bingo!
It takes TORQUE to get heavy V hulls up on plane. High revving screamers without gear boxes, do not get up on plane. You need prop thrust to climb UP & ON TOP of the bow wave.

The PTB Yanked me off the pier the first time I held the stern rope and slammed the throttle to WOT. Good thing I had the throttle on a spring return to OFF, channel.

A 400 hp bike engine does not accelerate a 4500# Caddillac. A 500 CI x 250 HP does.

The PTB can plane in 20' to 30' It does about 25 mph, compared to cars going by.

The ESC is a Novak Super Rooster reversing. Hooked it up backwards 2 x to the trolling battery since 2001. Runs perfect.
It does not blow the 60 amp auto fuse in any type of show off running.

Rich
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Old 02-19-2008, 05:01 AM
  #81  
sowega flyer
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Default RE: Building a 7'6" Crackerbox

Cyclops2 is right- IMO. I believe what you should be looking for is torque not RPM. Any powerplant that you put in there will be heavy so a high RPM screamer with a small prop isn't going to do it. I have a 6 HP johnson outboard- it weighs in at 52 pounds not including gas. I believe it would power your boat pretty well with the right prop, but thats not going to be very scale.
Have you considered a custom made V-drive? I think a small, run of the mill, go-cart engine would do just fine if you were to make a V-drive transmission for it. You could gear it any way you want, and have enough torque to put an effective prop on it and drive it at a reasonable RPM. Say a 5 HP honda engine with a max RPM of 3800- if you geared your drive at 1:2, you would get 7600 RPM at the prop. With a sub-surface drive set-up, and the right prop, you would be in business. The only thing to figure out then, is how to keep it cool.
BTW, mounting the outboard inside the hull,with the lower unit sticking down will ruin any chance of a high speed boat. The "well" will hold the boat down, and not allow it to plane-plus it will be a very good way to add your boat to the bottom of the lake. Take a bucket of water and a cup. Put the cup in the bucket of water and allow it to sink. Now take the cup, while under water and turn it upside down. Try to pull the cup out of the bucket

Just my thoughts...
Old 02-19-2008, 08:57 AM
  #82  
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Default RE: Building a 7'6" Crackerbox

HOLLY BEWILLIKERS BATMAN! [X(] that one big cracker. Ever seen those small outboards made by TANAKA , SEARS . they are powered buy weed eater motors and driven buy flexshafts just like your weedwacker. the support tube is hollow and you can cut the flex shaft down to size. you could probably end up with a 10 to 12" tall outboard. bottom end is gear driven and it had a 8" ro 9" prop on it. might make a great powerplant for that cracker. i had a 3hp version a while back and it pushed a 12' jon boat around at 6 to 8 mph. might be what your looking for. good luck. keep up the great work.
Old 02-19-2008, 01:31 PM
  #83  
firelite_marine
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Default RE: Building a 7'6" Crackerbox

pssh... Ive got a 14' jon with a 1974 9.9 johnson and my speedometer hits 35mph. now what might be fun is to make it an rc and ride in it with the radio so i dont get a cramp in my arm from the tiller. thats a big cracker but i think justaddwater has a 96" fountain with twin inlines and I also recall seeing a thread on here about an 8' cat with a pair of inline tripples. so i'm confused as to why were talking real outboards for a 7' 6" boat when twin inlines with the right props might do quite nice on a boat this size. sorry, got carried away again. nice lookin boat.
Old 02-19-2008, 02:55 PM
  #84  
nieto1124
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Default RE: Building a 7'6" Crackerbox

IM SURE THE THREAD IS DRIVEN BUY THE ALMIGHTY DOLLAR. twin inlines probably about 3500.00 by the time the exhaust, drives and props are purchased. old weedwacker outboard about 175.00. heck he could put twins in for less than 500.00
Old 02-19-2008, 05:12 PM
  #85  
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Default RE: Building a 7'6" Crackerbox

Theres a lot of great "out side the box" ideas going around here. One thing is not being questioned - you have room to mount any motor you care to consider

I like the outboard conversion idea. I have a 4hp Merc in the basement for a similar idea I had brewing. While I think that torque is definately a worthy consideration I also think you will need an RPM range that will allow you to get some top end speeds out of her. The V twin brigs maxes out at 3600rpm which I am sure is less than most outboards. I have never used a tach on any of mine but would have to think they are in the 7k+ range.

I am thinking that the cracker has a lot more wetted surface (and weight) than the 96" fountain and as such might not be the best candidate for a pair of inlines. While they are powerful - I think the cracker might be running in a league of her own.

Another motor option worthy of consideration may be a 250-500cc bike motor. You will still have the clutch, you may even have some gear ratios to work with.
Old 02-19-2008, 08:28 PM
  #86  
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Default RE: Building a 7'6" Crackerbox


Is a Cracker ALMOST the same shape on the bottom as a Jersey Skiff ?

Rich
Old 02-19-2008, 11:51 PM
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Default RE: Building a 7'6" Crackerbox

No. A Jersey skiff has a totally flat bottom with round chines, a cracker box has a slight vee bottom and square chines. Doug
Old 02-20-2008, 02:56 AM
  #88  
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Default RE: Building a 7'6" Crackerbox

ORIGINAL: firelite_marine

pssh... Ive got a 14' jon with a 1974 9.9 johnson and my speedometer hits 35mph.

You need a new speedometer.




Old 02-20-2008, 09:29 AM
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Default RE: Building a 7'6" Crackerbox

On Plane. Ive also confirmed it with a 17' running alongside me. whens this beast of a cracker box gonna be done. I cant wait to see some videos. for the record, it was 22F when this picture was taken. I was an ice cube when I got back.
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Old 02-20-2008, 11:37 AM
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Default RE: Building a 7'6" Crackerbox


SAVE THAT JOHNSON !!
Old 02-20-2008, 03:16 PM
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Default RE: Building a 7'6" Crackerbox

just to awnser some other questions you might have. the boat looks much better now with a paint job, It doesnt way much, I check in at 6' 4" 250lbs. the motor has been kept in great condition and if I remember right, has a top rpm around 5500. aswell as my 57 apache rc the 14' was my other winter project. I bought the hull from a guy who had it sitting in a field for 2 years.
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Old 09-07-2008, 09:28 PM
  #92  
2005ARSENEAU
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Default RE: Building a 7'6" Crackerbox

Hi,

I finally found a Suzuki 9.9HP outboard motor that is about four years old but had the foot banged up. I got it at a steel of a price. I have taken it apart and I will be getting made a engine joiner that will allow the shaft and the exhaust to connect with the new foot. I will need to cut down the shaft at the proper lenght.
I also made some hardware out of stainless steel. I am now looking for a foot with the prop that would fit the build.
I am already thinking about paint ideas. I am not decided of going with base coat/clear coat racing colors or going with the mahogany look. I may go with both! I was thinking of going with the mahogany wood finish at the front and having the racing design colors, pealing off towards the back.
Any ideas outthere?

I will keep you posted when I get the motor mounted.
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Old 09-12-2008, 12:17 PM
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Default RE: Building a 7'6" Crackerbox

Great build, can't wait to see the finished rigging
Old 09-12-2008, 02:15 PM
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Default RE: Building a 7'6" Crackerbox

The engine looks to be in pretty good shape. And the best part of all: It says made in Japan! And is that an electric start? It looks like an electric start gear on the front, left of the engine there. Everything looks great. The only thing I would question is the strength of that rudder you made. I'm worried that rod is a little thin and would flex in anything over 15-20mph. Other than that, Awesome job and keep us posted!
Old 09-12-2008, 05:11 PM
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2005ARSENEAU
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Default RE: Building a 7'6" Crackerbox

Hi,

I did notice that the rudder maybe a little to weak for this boat, so I am making another one right now. I will post pics when finish. The only drawback that I see is I will not have reverse or neutral because I will eliminat the gear section. I will make a engine to gear box joiner that will allow the exhaust and water cooling to work.

I will keep you posted.

Thanks
Old 09-12-2008, 05:16 PM
  #96  
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Default RE: Building a 7'6" Crackerbox

Reverse is not that big of a deal, but nuetral, I would rig up something like a clutch or maybe a slip belt system. Meaning it would be belt driven with a tension pulley that could be engaged and disengauged by servo.... Neutral is pretty important to me, especially if it is more for show and not gonna be nailing the throttle all the time.
Old 09-12-2008, 05:42 PM
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Default RE: Building a 7'6" Crackerbox

if you want neutral why not a snowmobile engine?
Old 09-13-2008, 10:35 AM
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Default RE: Building a 7'6" Crackerbox

I have some very large props in stock e mail me if interested [email protected] chris
Old 12-28-2008, 04:34 PM
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Default RE: Building a 7'6" Crackerbox

Hello!

Working a litttle more on the Crackerbox build. I have found a old Mercury 40hp racing outboard motor that has a smaller and narrower gear box. It also has a stainless prop that may be to big. I've cut the leg to the appropriate location and I will weld a aluminium mounting plate, that will join the motor mount to the lower leg. ( You will notice on the pics that the blue motor mount is temporally sitting on top of the grey leg where there will be the mounting plate). This aluminium mounting plate will also allow me to attach the unit under the boat and secured. As I see it, everything will be alligned perfectly. I will be keeping the exhaust and the water cooling at there location. The racing Merury motor didn't have reverse or neutral. That may be a problem???

I also found a racing helmet and life jacket for the scale size driver. I will have its head turn with the rudder. I will keep you guys posted wth the build. I have noticed a few large builds on RCU and other sites. I guess I am not the only dreamer out there... Hey !!!

Thanks guys.
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Old 01-13-2009, 08:14 PM
  #100  
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Default RE: Building a 7'6" Crackerbox

that is some beast!
i must see this boat up close

glenn

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