Jon Boat to Bass Boat Conversion

[JiggMaster24]

Hey guys, I'm new around this website and I thought I would share my conversion process of an old piece of crap boat to a useable fishing boat. I'm sharing this because converting Jon boats to bass boats is becoming a big phenomenon and I would like to assist those who are trying to do this. This is the whole process minus adding the carpet, enjoy! 

Converting a Jon Boat to a Bass

I purchased a 1962 Polar Kraft 14 FT. V bottom boat from a friend. I bought the boat, trailer, and motor for $500 (pictured below). The motor that came in the package deal was a 1957 Johnson 18 HP outboard motor (later sold & currently searching for a new motor).

For the price I paid, the boat was actually in really good condition. First things first, I pulled the bearings on the trailer, cleaned them, and repacked them. Next I stripped all the paint off the outside and inside. 

After all the paint was off the boat, it was time to tackle the transom. Because this boat uses a wood transom and the current transom was falling appart, the whole thing had to be ripped out and re done. Pictured below is the back of the boat after I ripped all the rotten wood out.

Finally the boat was back to its bare naked self, and I could finally start the conversion process. First things first I lightly sanded the boat, and I gave it a fresh new layer of marine grade paint. After that I reinstalled the transom.  The transom is constructed with advantech (which is a high quality treated type of plywood meant for water applications) and held together bolts with marine grade rubber washers to resist rot, and provide a good watertight seal. You can see the boat after this process in the pictures below.

Now that the boat is painted and the transom is complete, now its time to begin construction on the front deck for fishing. It took me a long time to decide on how I wanted to go about building a casting deck, but finally I came across a picture while browsing the internet that assisted me in the planning process. The picture below is the framing design that I followed.

The materials needed for the frame are minimal (6 treated 2X4's, metal framing brackets, galvanized deck screws, & 7 carriage bolts with washers and nuts). Pictured below is the complete frame building process from start to finish

Casting Deck Framing Process

Step 1: I had to put these two 2x4's on top of the seat as pictured, to ensure that the deck was level, and that all joints of the frame were flush to ensure a flat level surface for the plywood to sit. These two pieces are attached with 3 carriage bolts each to serve as the anchoring point for the deck.

Next I cut this piece of 2X4 to provide an anchoring point for the front of the frame. I cut the angles to match the angle of the boat, and attached it with a carriage bolt with lock washer. (This piece is attached to a vertical metal bracket that is supposed to serve as an anchor attachment point, so most boats may not be able to follow this option).

Next begins the framing process. I measured twice, and ensured all angles were spot on. Pictured below is the process of building the frame.

Most joints throughout the frame were attached with galvanized deck screws, plus these metal framing brackets that you can see in the pictures above. You may notice that I stacked five 2x4's in the middle of this section pictured above, this is to provide a sturdy base for my pedestal seat.

Now that the frame is complete and secured to the boat, its time to get some plywood and cut it to shape.

So the plywood ended up being a lot more tedious than I imagined. This was because the back edge of my deck frame was wider than 4 ft, and as everybody knows plywood only comes in 4 ft wide sections. So to cover my deck with plywood, I just turned the plywood sideways across the front of the boat. I then traced the outline of the boat with pencil onto the plywood to give me the rough dimensions of the boat. I then had to trim the edges in order for the plywood to sit flush on the deck frame which is sitting inside the boat. Now because we had to turn the plywood sideways, there was a small gap remaining in the plywood at the very front of the boat, as you can see in the picture below.

Because of this gap, now I had to cut a small piece of plywood, to fit inside that gap. This was easy, I simply used cardboard, and created a template for the small section. Where I ran into a problem, is now how am I going to attach this small piece to the rest of the plywood? Well after a long thought process I decided to attached both pieces with liquid nail to create a seamless surface, and also I used small sections of scrap wood and secured those to the underside of the seam to provide more stability. You can see this process in the pictures below.

After the liquid nail dried, this seam was not only seamless, but also very sturdy. All that was left was to cut a notch in the very point of the plywood to provide space for wiring, and then the plywood for the deck was complete!

The next step in the building process is to cut a door, to provide access to the huge amount of storage space underneath the deck. I had to think for a while and decide the doors position and what shape it would be. Because my trolling motor would be hanging over on the left side of my deck, I decide to cut one door on the right side of my deck. To provide the door with good stability, I added two more 2x4's to the frame to establish the shape of the door. You can see this in the picture below.

Next to ensure that the door would be precise I had to trace the shape of the door on the plywood. This required my 6'3" frame to climb underneath the seat to access the underside of the deck. After much wiggling, I traced the outline of the underlying 2x4 frame to provide a template for cutting the door.

So I would not have to add supports to the door itself, I measured 3/4 of an inch
(half the width of a 2X4) to provide a lip for the door to sit on. You will see what I mean in a second. But next I grabbed the jigsaw, and cut the door out of the plywood. You can see the completed door in the pictures below.

All that is left for the door is to add hinges, but we will worry about that later. But as you can see, when the door is shut, it will rest on the 2X4 frame underneath to provide a sturdy and functional door to access my battery, and other storage space.

Next all that is left is to add carpet, mount my trolling motor, and install my pedestal seat. Stay tuned!!

[Murrica]

Great step by step process.  Are you going to do anything for a rear deck?  Or are you going to leave that open?

[Tim Kelly]

Do you think it will be stable enough as the deck is very high?

[MDBowHunter]

Looks good and strong, but very heavy. 

[FloridaFishinFool]

I did a conversion for my boat too, but when I researched for materials I found that I should never use any pressure treated wood because the chemicals used to treat the wood are corrosive to aluminum. I even replaced the running boards on the trailer so it would not sit on corrosive treated lumber.

So when I did my conversion I did not use any wood at all. I used only aluminum framing and aluminum 1/4" plate for the transom, and I used expanded foam PVC board for the decking.

So none of the materials I put into or on my aluminum boat are corrosive, none will rot and deteriorate either. And, on top of that, my front casting deck in physical weight of materials is far less than treated wood which can be heavy. And none of the materials I used on my boat soak up any water at all.

So keep in mind that using wood, it will soak up water like a sponge and get even heavier. It can mildew, and mold, and it will eventually rot out and need replacing yet again, if the soft aluminum hull survives intact without serious corrosion issues.

And, you gotta be careful of the metal hardware you use on the aluminum too. Using dissimilar metals causes galvanic corrosion. " Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact,"   mmm so when two different metals are in contact with each other, guess which one loses the corrosion battle? The weakest metal, and if the case of aluminum boats, it is the aluminum that is eaten away to nothing. My boat had this problem from a previous owner who was clueless. I had to repair his mistakes. So to avoid this problem I simply ordered all aluminum hardware, aluminum hinges, etc. I did use some stainless steel in specific location in the transom where stronger bolts were needed, but not on the hull where it is normally wet or below the waterline.

And this brings up another issue of aluminum boats. Do not connect your battery or electrical system to the hull of the boat! This will speed up the galvanic corrosion process big time! Always float your electrical system and wiring on an aluminum boat! Do not use the boat hull as part of your electrical distribution throughout the boat! Keep the electrons away from the hull or else!

So please keep this in mind as you move forward.

Another issue I see with your conversion is you are trusting the seat rivets to hold the front casting deck. Over time you will be stepping up and down and up and down on that casting deck. Those seat rivets holding the seats in are going into the hull which is very thin. How long do you think it will be before those rivets start to wear and give out? For my conversion I took this into consideration and created a heavy duty rear L bracket to hang the back of the casting deck from the heavier top railing so I don't run into a problem of tearing out seat rivets from the hull- because they were never made for that type of loading.

Another issue I am wondering about is the paint you used. No doubt you used a good paint but what about the primer? Was this directly onto bare aluminum or was the boat previous painted?

Paint tends to not stick on bare aluminum. So there are specific primer paints used for bare aluminum, and they are not cheap! And it is not just a paint, it is a chemical process of surface etching the aluminum so the primer can get a grip or foothold on the bare aluminum to stick to it. Then the top coats can go on.

When I did my boat I contacted an epoxy chemical engineer who helped me through the entire process. The aluthane primer was $100, and the top coatings of epoxy were also about $100 and I used the same outdoor UV rated epoxy paints that are used on large ships, bridges, and water towers, the best made because I figured if I was going to do it, I was only going to do it once and do it to the best it could be.

Here are some images of my conversion:

All solid aluminum 1/4" plating. No corrosive treated wood used in repairing this transom! This plate cost around $150.00 and I cut it by hand using a template I had drawn by hand and fit onto the boat before transferring the image onto the aluminum plate. I had only one shot at this and it had to be right the first time!

No welding of the upper bar across top of transom. Welds in this location tend to crack and fail as the previous owner found out. So I used bolts to act like hinges when the top of the transom flexes under thrust loads. I designed it to flex. I used just two pieces of aluminum for the transom repair and in 3 years no issues. It is now 3 times stronger than factory and no wood to rot out. This transom can now outlast me!

Here are images of the transom welds cracking and failing from the previous owner. This transom knee weld is cracked 4/5's of the way around the top of the knee just under the outboard motor mount:

Here is a welded side thruster bar the previous owner installed. Also cracked. This is what happens from years of flexing under load. I wanted my repair to avoid this problem and I have succeeded so far since I have no welds to crack now.

Here is an image of the front casting deck under construction. The front two cross members are mounted on the seat mounts on the hull, but I knew I would tear out those rivets eventually if all I used was the seat rivets to support the rear of this casting deck, so I hand cut and hand hammered into shape some custom L brackets I hung from the top railing using 3 aluminum bolts to give me the needed strength and support the back of that casting deck would need for having full grown men step up and down from it day after day, year after year. I was not going to trust a couple tiny little rivets drilled into a thin hull for that support!

Here is an example of galvanic corrosion from the previous owner who installed his own oar locks using all steel hardware. You can clearly see the outline of the steel washer he used and how where it got wet over time ate through the softer aluminum hull. I had to make custom all aluminum washers to cover these hull breaches. This image was taken after the final epoxy coats & before the repair.

Here is an image of hull corrosion I found under the transom knee when removed. The boat was leaking here. It was caused from salt water use and the salts were not rinsed out and over years caused this corrosion.

I would like to show you some images of a second boat I was given that I was not able to restore due to 30 years of salt water use completely destroying the soft aluminum hull. This boat was a 1983 alumacraft outfitted for salt water use. When water and salt reached the wood on this boat, the corrosive results were catastrophic. Even sitting on a trailer with treated 2X4's under it severely corroded the hull beyond use and beyond repair.

Here is the transom wood before being torn out. Notice it is rotten enough to hand stick a screwdriver into it and all the white is dried up salt crystals. Some salt crystals on this transom board were 1/4" thick!

Now take a look at what it did to the hull in the transom:

If light can shine through, then water is certainly getting through!

Salt and aluminum do not mix!

Just look at all that hull pitting and corrosion! This is from using wood, combined with salt and water. It ate this hull up!

 

Here is an image of what happens to an aluminum boat hull when sitting on treated lumber on a trailer combined with salt water:

I am posting this to be helpful in communicating some of what I have gone through when converting my own boats. And I will follow this same path for future boats as well. I hope this information will be of value to you in your own conversion.

My nearly finished conversion:

I'd like to add a couple of things... before buying any aluminum for this boat, I contacted alumacraft and asked them what type of aluminum was used to build this boat. Once I got that information I could then buy matching aluminum so galvanic corrosion would be at a minimum. There are different aluminum composition alloys and I did not want to buy differing metal alloys that could interact with each other in a negative way, so I tried to match aluminum alloys as closely as possible.

Next, the way I did this conversion is recyclable. If this boat should fail I can always buy another boat just like it for under $500 and remove all of the parts I used for this boat and re-install them into the new boat with little to no fabrication work. And virtually no additional costs too! Alumacraft sold tens of thousands, if not hundreds of thousands of this exact same model starting in the mid 1950's up through the 80's. Next time I will look for one in a state with no salt water anywhere near it! No more salty dogs for me!

This boat is a 14' boat, but alumacraft also made a 16 footer same as this one with 2 more feet added to the back of the boat. Same dimensions, so these parts I made for this boat will transfer over to the 16 footer too!

[gulfcaptain]

I like your idea, but you should have used a marine grade plywood, used fiberglass resin as well as some cloth to seal the wood and all joints.  You used treated wood which is good, but you need to do something to protect the plywood casting deck otherwise your hard work is going to warp and delaminate under that carpet as well as mildew and rot from the inside since it's aluminum and a big cavity underneath.  Just observations from working in the marine industry and doing a bit of reconstruction on wood/fiberglass boats.  Overall, not bad.  Not sure about treated lumber(2x4's), we just used regular wood but always marine grade plywood and always sealed the seams with a marine adhesive (4200 on screws and 5200 on seams) and then glassed over to prevent water from getting to the wood.  Also may have mocked up your deck and then taken it to the lake and seen how it balanced incase you have too much weight up top causing it to be tippy.  Remember these are just observations and not knocking your work.

[JiggMaster24]

3 hours ago, Murrica said:

Great step by step process.  Are you going to do anything for a rear deck?  Or are you going to leave that open?

I'm gonna leave it open because I also use this boat for duck hunting, this is why I made the deck so I could remove it during duck season 

3 hours ago, Tim Kelly said:

Do you think it will be stable enough as the deck is very high?

Because my boat has a V hull, the boat won't be the most stable ever, but I've been in V hull boats with front decks, it just takes some getting used to.

@FloridaFishinFool @gulfcaptain wow thank you for all the information it will be very helpful! As far as the chemicals in the wood, every piece of wood, including the plywood was sealed with waterproof sealer, and I put plastic underneath the wood where it comes in contact with the boat. And as far as stability, I had a friend that used this exact process and his boat was really stable. But since this is a V hull boat it will always be rocky, it just takes some getting used to. Thanks again everybody for the info!

[gulfcaptain]

1 hour ago, JiggMaster24 said:

I'm gonna leave it open because I also use this boat for duck hunting, this is why I made the deck so I could remove it during duck season 

 

If you're making it removable, take the extra time to glass the wood from below.  Your sealer is a start.  But you are going to end up doing it often.  Use a good resin and seal it. Tape the seams.  Make it a solid deck and the work you put into it will last a lot longer and won't have to worry about it.  You waterproof sealer will wear off and if there are any spots in the wood you missed (like between the joints) the water will find its way in.  Wrap fiberglass tape around the ends of the plywood (use thin tap) and then sand smooth.  This will insure your hard work lasts.  And screw hardware for your hatches, use 3M's 4200 adhesive.  Use stainless hardware or brass if you can as well instead of galvanized.