finished the jack plate project

[danderson]

well, in order to solve the hydrofoil problem that a few of us have been talking about on the site, i made my own jackplate! most of the assembly was done by my more mechanical friend andrew. heres the specs

went to chicopee welding and had them put 4 bends in 5/16 steel. we decided this jackplate had to be beefy and were originally only going to go with 1/4 steel, but this is all they had available.

from there, we brought the steel back to andys house and while i looked for my starter and worked on the pull start on my engine, he assembled the jack plate.

oxy - asetolene (idk how to spell that one) was used to put the 8 slits on the side of the plate to intelock using bolts. then andy welded a bar 3 inches from the top so the plate automaitcally raises my engine the requirered 3 inches i had needed.

he then did the fancy stuff and welded a bolt through the middle to allow easy adjustment. and here is the product!

she weighed in at 58 pounds worth of steel! and cost $60 to create (plus the welding supplies, but andy already had that coveredBeerchug )

http://i70.photobucket.com/albums/i119/danderson_pike/jackplate001.jpg

4 inches of travel, up or down!

http://i70.photobucket.com/albums/i119/danderson_pike/jackplate002.jpg

http://i70.photobucket.com/albums/i119/danderson_pike/jackplate005.jpg

the easy up bolt mechanism

http://i70.photobucket.com/albums/i119/danderson_pike/jackplate004.jpg

http://i70.photobucket.com/albums/i119/danderson_pike/jackplate003.jpg

[Gary P]

that's cool, now get it chromed!

[Crestliner]

Outstanding job! Now just get a patent on an aluminum rendition and you'll be our next MaAngler's millionaire! Have you tried it yet? How did you determine that you needed to raise it 3"? I know I still have to raise mine more, but I don't know by how much. I like the adjustable feature of your project. Fine job indeed. Please keep us posted on the results!

[danderson]

that's cool, now get it chromed!

is a can of aluminum colored rustoleum paint good enough?Tongue1 Grinning1

Outstanding job! Now just get a patent on an aluminum rendition and you'll be our next MaAngler's millionaire! Have you tried it yet? How did you determine that you needed to raise it 3"? I know I still have to raise mine more, but I don't know by how much. I like the adjustable feature of your project. Fine job indeed. Please keep us posted on the results!

i knew my engine needs to be raised at least 3 inches because the top of my cavitation plate is 3 inches from the bottom of the boat. i'm actually rasing my engine an additional 1 and 1/4 inch up until the prop is barely below the bottom of the boat, for max performanceBeerchug Thumbsup


crestliner, can you send me a picture of the stern of your boat with a ruler for comparison next to the prop and the shaft of the engine. for best performance, all engines should have the cav plate at the bottom of the boat. if you more space between the top of your prop and the bottom of the cav plate, you can still raise your engine a little more but you run the risk of cavitation burn (i'm sure you know what it is)

once i get the new electric starter in my boat (if i ever find the thing) i can get you some resultsMachineGun MachineGun MachineGun

[danderson]

some more perks i forgot to add, this is PVQ steel, my engine wont be going anywhere incase of accident Thumbsup and that it allows me to drop down far enough to properly use my 4 horse kicker for quabbin!

[JeffA]

wow, good job.

[Uncle Rickers]

Awesome job. Now get her running and let us know how it works. You do have issues if the electric starter is missing, and the pull rope doesn't work. Maybe someone could offer some help if you detail the problems.

[danderson]

nah, i'm actually pretty good at repairing outboards. and the rope starters fine now, i just hate using it. actually, the only things i cant do on my own for an engine are reboring a piston/resleeving. other than that, between me, james and andrew, we're our own OB repair shop (we're actually thinking of opening our own shop in october!)

[seabass]

Thumbsup great job and ingenuity u guys - that looks like it'll work just fine and the travel you have wil help move it up and down without all the hassle WTG!!!!
Bow1 like cresty said...make it out of aluminum and take it to a patent office.Bow1 Beerchug

[Crestliner]

danderson - Here are some pictures of my stern engine position after raising it 1 1/2" above the transom. From what I can see visually while running at WOT, the fin just above the Doel Fin, is just breaking above the surface(?). I could be wrong; it's difficult to determine, looking over the stern while running WOT Yikes! You can see the water line as well in the pics. Is this of any help?

http://i146.photobucket.com/albums/r251/Crestliner_photos/HD1.jpg

http://i146.photobucket.com/albums/r251/Crestliner_photos/HD2.jpg

http://i146.photobucket.com/albums/r251/Crestliner_photos/HD3.jpg

Let me know if you need to see more Notsure. Thanks for your input!

[danderson]

from what i can see, you have a semi v, so this is going to make it tricky. but heres my idea

it looks like you have a small prop, and some space to spare between the top of the prop and the bottom of the Cav plate. you definitly need to raise your engine up, but because of your semi v design, you may not be able to get all the hydrofoil out of the water before you start to get cav burn.

i also noticed that you have 3 bolt holes on each side to choose from, so i would say forget your transom clamps now and just use those bottom 2 bolt holes and raise your engine up with those. there is another alternative to a jack plate
you can raise your engine up with plywood and a board clamp on to those then use your available bolt holes to truely secure the engine

[pondhopper]

Is the hydrofoil still well below the bottom of the boat? Looks like it may be as much as 4 inches or so lower but it is hard to tell from those pics.

What is the measurement from the bottom of the transom bracket to the bottom of the cavitation plate. This will give you the actual shaft length. http://www.smalloutboards.com/shaft.htm

I am thinking that the shaft is too long for that boat.

[Uncle Rickers]

Great Link. That site pretty much explains it all. Good luck gentlemen.

[Crestliner]

danderson - First off, she is a "deep-V" hull; all Crestliner "Sportsman" series boats are DV's. Don't forget, you're only looking at the stern in these pics. As far as drilling holes in the transom; originally, when purchased last year, it was drilled and bolted, with the engine frame resting on the transom. I removed those bolts and raised the engine twice now using wood blocks and only using the clamps for securing. Now what you're suggesting is to drill more holes in lieu of any other option - until I find the correct height? I think NOT. LOL! Once I find the correct height, then - and only then - will I consider re-drilling that brand new transom! This boat represents a considerable investment to me my friend; punching a bunch more holes isn't a viable option, from where I'm sitting! Please tell more about this "plywood" alternative?

pondhopper - please re-look at my boat pics from yesterday on this thread; you will see the position my hydrofoil is, in relation to the stern. I'd guess it's only about 1 1/2" - 2" from being even with the keel(?). Tough for these old bones to lay down on the ground for a straight on view, but I did the best I could!

I really do appreciate all your inputs on this problem; I believe if I can solve it, it will benefit a lot of other folks thinking about buying a new boat and/or improving the performance of their existing rig. THANKS muchly!

[pondhopper]

pondhopper - please re-look at my boat pics from yesterday on this thread; you will see the position my hydrofoil is, in relation to the stern. I'd guess it's only about 1 1/2" - 2" from being even with the keel(?). Tough for these old bones to lay down on the ground for a straight on view, but I did the best I could!

I really do appreciate all your inputs on this problem; I believe if I can solve it, it will benefit a lot of other folks thinking about buying a new boat and/or improving the performance of their existing rig. THANKS muchly!

Ok then Now I have better idea of how it sits I can better understand how to advise you. Hopefully your guess is accurate. You can measure it accurately just like I told you how to do the prop shaft measurement in the other thread. If your guess is later found to be innaccurate then you will just need to adjust my suggestions by the same amount as the difference between your guess and the actual measurment. No biggie.

In order to get that Hydrofoil out of the water when on plane you need to come up at least the 1 1/2 to 2 " you are now below the bottom of the boat. According to that webpage it is ok to be within an inch either way of the bottom of the boat. That would allow you to come up 2 12 to 3 inches more. That will make a huge difference in drag. Short of putting a manual jackplate this may be the ticket.... http://www.iboats.com/Transom_Elevators/dm/session_id.365572583--cart_id.264541855--category_id.217144--list_time.1188418090--view_id.40157

Looking at your prop it does look small. You say it is a 9 pitch. Is it the same diameter as the other prop? What is the other number. Should be ## x 9 or something similar. On my Tracker with the 25 I used to run a 10" x 13" which is a 10 inch diameter by 13 inch pitch prop. Also what are the specs on the original prop?

Another question is, have you tried the original prop since you moved the motor up? It is easy to swap props and the smaller prop may have you operating out of the powerband.

What I would do if I were you is try to get that cav plate up to around 1" above the bottom of the plate, put the old prop back on and take her for a spin. I bet you will see significant improvement.