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How to build your own Jackplate


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#1 OFFLINE   firecat1981

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Posted 28 April 2010 - 01:24 PM

Ok guys be gentle, this is my first How-to article.How to build your own jackplate.This article is about building a simple, light weight, adjustable (in 1 inch incraments), budget minded jackplate. It is intended for those who either can't afford, or simply don't want a larger hydrolic unit. The whole project can be finished within a day's time and when adjusted properly can allow you to get better performance, both speed and running draft, out of your boat. Please note these plans are for smaller motors, but can be adjusted to be used on larger motors within reason. Please see my builder's notes at the end for more detail.What you will need:- 4 pieces of 3x3x1/4" aluminum angle cut to 12" long.- 2 pieced of 3/4" plywood 11x10" (for the motorboard)- epoxy to laminate the motorboard.- paint (optional for the motorboard and jackplate.- 3/8" drill bit- 3/8" hardware SS = 4 1" bolts with washers, nuts and lock washers. (for the adjustable sides) = 4 2.5" bolts with washers, nuts and lock washers. (for attatching the motorboard to the JP) = 6 bolts (size depends ont he thickness of your transom) with washers, fender washers, nuts and lock washers. (to attatch the JP to your boat)Start off marking the aluminum, and drilling the 3/8" holes. here is the pattern I used, all the holes were drilled 1.25 inches from the edge. The pattern can be adjusted if needed:AluminumPosted ImagePatternPosted ImageWhen finished it will look like thisPosted ImagePosted ImageNext you need to drill the holes to mount the jackplate to you transom, this is the pattern I used, I did not give measurments because you will need to adjust the height first then drill the JP accordingly.examplePosted ImageNow you need to start on the motor board. It is easier to cut the 2 peices of plywood slightly larger and then trim them after lamination. I went with 11x10" because when I mounted my motor it allowed me to bolt it through the motorboard and the aluminum. I used epoxy resin thickened with sawdust/wood flour to laminate mine, but if you have some 30 minute, or one hour epoxy around you can use that too.Laminated and clampedPosted Imageonce it is dry, trimmed and sanded you can drill the 3/8" holes through the aluminum and motorboard. Just make sure that where the bolts are won't interfere with clamping the motor down.Test fitting the motorboardPosted Image At this point you can size up and drill your transom. you can move the plate up some, but I would leave atleast 9.5" or so below the top of the transom to maintain strength. Use clamps to get the position right, mark your holes and drill the 3/8" holes. (Note - 4 bolts may have been enough, but with 6 of them the jackplate is rock solid!) Remember to seal any exposed wood with epoxy!ClampedPosted ImageDrilled and test fitted (ignore the small washers here, I just used them for fitting because the fender washers were not withing reach)Posted ImageNow all that is left is rounding the corners, with either a jigsaw or grinder, and smoothing the surfaces. As stated earlier painting is optional, but you really need to paint the motorboard or it won't last very long. I epoxy coated mine then hit it with a few coats of krylon.Rounded corners and painted board (notice the small piece of cutting board in the middle of the aluminum, I put it there so the clamps sat flush)Posted ImageOnce you hang your motor be sure to drill the holes to bolt it to the jackplate. If you plan on painting the aluminum I would do it after you have found it's final running position or the paint will get scratched up while you are adjusting it.Finished jack platePosted ImageBUILDER'S NOTES:I based this design loosely off of Dillon Racing's design but decided to change it to better meet my needs. With the 3x3x1/4" aluminum this jackplate can easliy handle up to 25hp motors. The original plans called for 4x4x1/4" aluminum and was rated for 40hp motors. If you needed it for an even larger motor you could use 3/8" angled aluminum for up to a 50hp motor. This set up gave me about 4.5inches of set back, but if you decided you need more set back you can buy 4x3 aluminum and get another inch or 2. Total cost for me was less then $50.

#2 OFFLINE   livetofish

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Posted 28 April 2010 - 01:29 PM

You are one talented firecat. Amazing your out of pocket was only $50.

#3 OFFLINE   firecat1981

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Posted 28 April 2010 - 02:33 PM

Thanks man, but really anyone can do this, or anything else I've done. It just takes time and a little bit of money.

#4 OFFLINE   surfman

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Posted 11 May 2010 - 11:31 AM

Thanks, good job with the details.

Tight Lines,

Steve


#5 OFFLINE   pappoose

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Posted 02 January 2011 - 03:57 AM

i think i have to build one i have a 16 foot flat im currently doing i got a 1986 28 hp spl evinrude cheap but strong motor its a long shaft is there a set spot where the propeller should be below the transom im kinda new to this but i can build that jack plate i just want advise to how low should my prop be at the bottom of the boat im guessing two inches

#6 OFFLINE   firecat1981

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Posted 02 January 2011 - 09:00 AM

It's not really measured from the prop, it's usually measured from the cavitaion plate right above the prop. If you have a long shaft motor (20 inches) and your transom is 20 inches then the cavitation plate should be about equal with the hull bottom on a flat bottom boat.There is no set location that works for every boat because of different hull designs, motors, loads, and balancing of the loads. That's why most jackplates are adjustable, you need to do a few test runs to find what works best. I will say the general rule of thumb for smaller boats is for every 2 inches of set back you can raise your motor +/- 1 inch. If you have a cupped prop you can usually get even more out of it before it ventilates (which will make it feel like it's studdering)Are you looking for better performance, or are you trying to fit a long shaft motor on a short shaft boat?Hope that helps

#7 OFFLINE   pappoose

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Posted 02 January 2011 - 12:15 PM

okay my boat transom looks real short i havent measured it yet i will be getting the motor in week or so but soon ill measure every thing and try to get pictures like i said im new to boat this my 1st project ever but here i go just found out yesterday what a transom is lol but firecat yeah man i got a 1986 evinrude spl 28 hp long shaft rebuilt tip top shape but i was reading about how jack plates can make a difference about keeping the motor in cleaner water and something about the turbulance coming from the boat bottom also being able to trawl in shallower water not really looking for speed i live in louisiana we have some good shallow canals here fish is abundant everywhere i just want my motor to be in a good spot to have how you say no problem fishing as far as prop being in mud etc or shallow water safety driving i hope you understand me firecat cause i really think ill have to make a jack plate just like you have i really like that design also i wanted to ask with a 4x4x1/4 that should hold up to a 40 hp i notice you used a 3x3x1/4 with a 28 hp motor i know the 1986 evinrude dry weight is 118 lbs but later a few years from now i plan to go up to maybe a 40 hp motor so i wonder if it make better sense to go with the 4x4x1/4 or 3/8 just incase i upgrade soon Posted Image

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#8 OFFLINE   pappoose

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Posted 02 January 2011 - 12:20 PM

okay i got a picture up not a good picture for detail but this the boat im redoing i will sand it etch prime it with duplicolor then paint duralux green ill take some better pictures in a few minutes for you to see my transom area so you understand what im working with firecat thanks for anwsering me cousin i hope get it right im learning as i read stuff online lol but i love fishing man happy new year so glad i found this site you mite be a life saver for me Posted Image

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#9 OFFLINE   pappoose

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Posted 02 January 2011 - 01:02 PM

Posted Image this a few pix of my transom please dont laugh at at me she been hit by hurricane katrina and all i lost everything plus i aint rich like most fishers but she will look good when um done i put up more pictures as i go :unsure: also i was thinking of going with a square piece of aluminum 1/8 thick on the back where they drilled all those hole to make that outside wall more flush for my jack plate.

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#10 OFFLINE   pappoose

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Posted 02 January 2011 - 01:07 PM

i will pull that 2x6 treated wood out cut it and put another piece at the bottom behind that bracket to make it stronger i think i will upgrade to a 40 hp later i think it would give me more of something to bolt down to Posted Image and then come with a fresh new c channel to cover the top along the back maybe the length of my jack plate because the bracket in the back is split from the top. To make it stronger with a new c channel then grind everything smoother prep for paint i was wonder how hard is it to weld aluminum

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#11 OFFLINE   pappoose

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Posted 02 January 2011 - 01:09 PM

i was thinking of going with a square foot aluminum plate 1/8 thick to make this back flush and cleaner also the inside make it more stronger flusher and cleaner where they drilled the holes i will cover that with a thin plate before putting the jack plate on it Posted Image

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#12 OFFLINE   firecat1981

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Posted 03 January 2011 - 01:59 PM

pappoose, Find a buddy who knows how to weld aluminum and fix that sucker strong before even thinking about hanging a motor on it. I say this cause nothing is worse then smacking the bottom in shallow water, hearing a splash, and looking back to see your outboard hanging on by the fuel line. Ask me how I know :laugh: .It's hard to see from the pictures what you really have going on, but I would definately straighten out all that metal and then weld in some extra supports. Find a scrap metal shop in your area and you can get stuff cheap. I've had friends who replaced there transoms with diamond plate they got from scrap yards. Either way find someone who knows a bit about boats to check it out for you and make sure it's solid. The reason I'm stressing a solid transom is because you have a short transom (15") from the looks of it, but you say the motor is a long shaft (20"). This means you really need to build a riser plate just to get it to work right on the boat. Measure everything to confirm. Basically you can build a jackplate to raise it 5-6", but this will put alot of stress on the transom by turning the motor into a lever. Think about jacking up a car, the longer the handle the easier it it, same thing here so you need to make sure the transom is bullet proof or else you can have a major failure while running!You can go with 3/8" if you want, but in your situation you will want as little setback as possible to lessen the stress so I would use 4"x3" angled aluminum. The 4" sides will go towards the boat and motor, and the 3" sides is where you will drill the holes to adjust it. The mounting bracket (attatched to the transom) will need to be atleast 5 inches longer because of the motor you are using. This way it sits 5 inches higher. Honestly I wouldn't worry about performance right now, just see if you can get it to the proper functioning height (cavitation plate equal with the bottom of the boat). And if you buy a 40hp in the future, make sure it is a short shaft (15") motor. you can always cut down the bracket if need be.

#13 OFFLINE   pappoose

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Posted 03 January 2011 - 08:24 PM

okay i will see if i can weld it myself i can do things like that im pretty crafty just got to find the equipment the transom strong just the c channel been split by whoever had the motor before my dad got it but i think ill do like you said weld a stronger c channel on the back and stiff up the back wall where i had the 2x6 ill split that bolt it down also i found a guy in detroit ebay got the jack plate metal if home depot dont have it down here and i know the motor im getting just 118 lbs but i will take into what you saying cause im learning my cousin live next door he welded aluminum rig for his shrimp boat so i guess he can show me how to do that but this what i did today sanded and etch primed front deck a a lil side wall with duplicolor etch primer Posted Image Posted Image

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#14 OFFLINE   captaindavid

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Posted 04 January 2011 - 12:38 AM

firecat1981, You impress the heck out of me with these projects. Shoot me a pm with your personal e-mail.

#15 OFFLINE   pappoose

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Posted 04 January 2011 - 02:26 AM

firecat i got some info on durafix so i read bout that when i get to the transom area thats what ill do fabricate the back up like you said bolt the wood down add the c channel then weld everything in thanks man for your help i think i will make a whole new backwall with aluminum plates and well you will see later man

#16 OFFLINE   firecat1981

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Posted 06 January 2011 - 11:26 AM

pappoose - I don't know anything about durafix so I can't advise you on it, but if it does as it says then it should work out well. I would still add some additional diagonal (corner) bracing if you put a 40hp on later, but I'm sure you will be fine.Now lets talk about this "rich fisherman" deal here :laugh:. Most of us started out with nothing, and you will see most guys with big fancy boats are very well established and worked there way up. There are still amny guys, including me, that don't have alot of cash so we fish smaller cheaper boats and make our own accessories (like homemade jackplates ;)). In no time you will find that little by little you will be rigging out that boat and it will make a fine fishing platform.CaptainDavid - nothing very impressive about my stuff, just takes time, a little money, and be willing to try. Heck all this jackplate is is a few holes drilled in aluminum and bolted to some plywood.

#17 OFFLINE   pappoose

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Posted 06 January 2011 - 12:29 PM

you right firecat man since hurricane katrina trying to get back to the basics still hard but we getting stable again so i am building this boat for my dad so we can hit the waters soon ill post pictures as i go but will take every advise i need and can get from guys like you because i am learning plus my dad always working busy and i do have a very cool older cousin next door who been helping along the way yesterday man he gave me a gallon of paint duralux pigoure green also he has welding experience plus him and my dad they boat alot so with all you guys advise i should be going in good places now can you explain the way and why you used epoxy on your 3/4plywood is that like a glue to make the boards stick together or is it something that coats to prevent rot cause i saw some aluminum plates i can get off ebay 1.5" thick i can get it 12x12 12x6 or the size i need since i plan to maybe add a 40 you think using the plate instead or wood would be better i talked to some guys who build boats to like backwoods landing they said they usually use 20 hp motors on 16 ft flat i have a 28 i read something bout the 1986 evinrude spl being a 28 but something about 35 hp output low end and 28 top end the guy i am meeting the guy saturday to pick my motor up from said he has a 15 foot boat and did 32 but he had all kind of stuff on his boat i will just have a 1/2" deck plus the steering helm he giving me and the navigation lights not planning to add no extra weight wana keep it light as possible but strong so if the boat move good with that motor ill stick with he said he never brokedown just serviced the motor rebuilt everything so i think the motor good he said its strong and dependable still waiting for my trailer parts from etrailer.com to be shipped so i an redo my trailer new hubs tires bearing buddies winch stand etc plus i will go with bunk slides now about the jack plate i see what you saying about having to rise a bit more so instead of going with 12" long aluminum angle bars i think i will go with longer plus use 3/8 for strength and last i do you think i should make the jack plate wider for more coverage strength i saw how you plate gave you enough room to mount your motor in middle of the plate too also let me know what you think about going with a aluminum solid thick 1.5" plate instead of wood :cheer: B)

#18 OFFLINE   firecat1981

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Posted 06 January 2011 - 01:22 PM

pappoose - I don't think I would go with the 1.5" aluminum block cause it would weigh too much and you want to keep the weight in the rear down as much as possible.The epoxy I used for 2 different reasons, first was to seal the wood, and second was to bond, or glue, the 2 pieces of plywood together. To bond the 2 pieces together you need to thicken the epoxy a little bit. You can use most anything to do that, but wood flour (or saw dust) is the easiest. mix the epoxy well with the saw dust until it's about cake batter thickness, then coat the 2 pannels with the thickened epoxy. Stack them on top of each other and put as much weight as you can find on top! Let it dry and then coat it with epoxy to seal it all. TIP - put down plastic sheeting or wax paper on the floor or else you might end up gluing the plywood to the garage floor!As far as the width of it, if you use the 3"x4" aluminum your mounting board will already be 2 inches wider then mine was and should be wide enough for the 40hp. The most important thing here is no matter how wide you build it, you must be able to bolt the motor directly to the aluminum! The mounting board is fine for clamping the motor down, but once it's clamped you must drill the mounting board and aluminum so you can through bolt it, especially since it will be remote steering. Otherwise you may not know the clamps came loose until the motor falls off.Go with 3/8" if you feel that is best, it won't hurt anything. You only need the pieces of 3x4 (or 4x4 if you choose) on the transom side to be longer. so you should have 2 peices of angle aluminum 17" long and 2 peices 12" long.One last thing I was thinking of is on an aluminum boat you will need a plate on the inside to spread the load better instead of fender washers. Nothing crazy, maybe 3/16" or 1/4" and enough to match your bolt pattern you will be drilling through the transom.

#19 OFFLINE   pappoose

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Posted 06 January 2011 - 03:10 PM

let me see if i got you i understand the epoxy i have some in my shed now but sand the wood before i epoxy seal for smoothness right. And on the boat angel bar that 4"x3" face the 4" side flat to the back of the transom and the 3inch side is 3" side is coming out to the other adjustable bars now the adjustable bars can be 4x3 or 4x4 but explain this again you told me about the setback thing if i go with 4x3 4x3 or 4x3 4x4 which one do you think would be better im guessing the farther back would put more stress to it then stay closer to the boat right i hope you understand

#20 OFFLINE   captaindavid

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Posted 06 January 2011 - 08:03 PM

I learn a lot from these posts