JEM Watercraft

Hello Matt,

Have really been enjoying your site, the forum and all the wonderfully, wacky conversations and comments....not to mention the amazing boats. Reading and looking at these have convinced me to give boat building a go!

Now, to the question. I paddle mostly Ozark streams and the occasional "Big" rivers like the Missouri. Looking at the bottom of my Wenona tells me these conditions are pretty tough on boats. The streams are shallow in many places with lots of gravel and rocks. I'm concerned about the hull getting beat up. Is there any way to make the hull below the water line bullet-proof without adding tons of weight?

Also, since I'm new to this sort of thing, I was thinking about "which" boat to build. The Freedom 15-4 is a sweet boat and looks about right but I was thinking as I walked past my Prowler 13 hanging on the wall....wouldn't it be nice if the Freedom came in a 13. Just now as I was crusing the "Southern Paddlers" forum, he mentioned you were working on Freedom 13 plans. Sweet! When will they be available? I'm thinking that if this boat comes out like I would like it, I will give it to my wife and build me a 15-4. I am trying to keep these boats light and strong yet easy to paddle and able to carry enough junk to make life comfortable for short camping trips, day floats, etc. Thanks again for a great site and I look forward to getting started....

Oh, one other thing. Outside temprature and resin. I have to buid this thing in my garage and right now it's 3 degrees! As the spring comes obviously tempratures will warm up, but do I have this right....the colder the slower the resin sets...and the hotter....the quicker right? So, when I order, I need to look for "fast" if it's cold and "slow" if it's hot. Am I understanding this right?

Thanks Tim

Bottom toughness:
I'd say build the boat with fiberglass coverage inside and out. Then on the outside bottom and up the side a couple inches, apply one additional layer of 4 ounce cloth. That with give you some extra stiffness and abbrassion resistence. Then, do this trick:

http://jemwatercraft.com/forum/viewtopic.php?t=134 .

It's applying graphite mixture to the hull bottom. Here's a picture of Chuck's.



Freedom13:
It's acutally 12'7 and the plans are ready now. I haven't had the chance to update the website. It's the longest Freedom hull you can get and still only have it made from 3 sheets of plywood instead of 4. I can send them to you if your order. Might take 2 extra days to ship so I can do
a final proof read.

Resin Cure Speed:
You are correct about the resin setting. You can order fast cure when it's cold or slow cure when it's hot. If you order from RAKA, you can get some fast and some slow and then use when approriate. You can even mix the 2 for a "medium" cure speed. Be sure to ask for the JEM Watercraft discount when ordering.

Tim,

The graphite on the bottom makes it a LOT tougher. I paddle waters of Michigan and Canada, lots of sharp, broken rocks to scratch and gouge. I have scratches that start on the graphite, and travel up onto the "standard" epoxy, where they deepen into gouges. Also, the bottom is slicker and slides through weeds and lilly pads faster.

I add about 20% (by volume) of powdered graphite to the mix. I add three coats of graphite-enriched epoxy to the bottoms. I move the masking tape back 1/8" for coats# 2 & 3 to have a staggered edge. Do coat# 2 one day after #1, and #3 one day later. This way they will bond chemically to each other.

Then, lightly sand the last layer to a light grey. BEWARE: this will produce black dust that gets all over everything. Do it outside, or plan on looking for a new spouse.

Heya Tim,

Welcome aboard mate.

Chuck is real pleased with his Freedom 15-4 and the 12'7" one should be just as good.

Mate, if you are looking at running some gravel races and such, I would consider using a thicker and harder piece of ply for the flat bottom panel in addition to what Matt and Jack have said. I would choose a piece of the hardwood, exterior bracing ply for the bottom panel only (just to take the abuse)

Thanks guys...it's great to know you're not "out there" on your own to figure it all out....I've got the benefit of all your collective wisdom! As she rolls along, I'll continue to keep you all up to date.
Tim

Tim,

Almost any mistake can be corrected with epoxy, wood flour, and fiberglass. Don't ask me how I know.

I took the Freedom 15.4 for a multiple day camping trip and it held my gear with room left over.

If you and the wife went out then you would be able to get the gear in the 15.4 and any spill over for two people could go in the 13. Thinking that a extra sleeping bag and a larger tent , 2nd camping chair along with food for two would fill up most of the space in the 15.4. Since you would have the 2nd boat then it could take some of the gear.
Another good reason to build two of them.

As you know these are solo boats and when paddling and camping solo there is plenty of room in the 15.4 for the one persons gear.

Just like when a person is backpacking with a buddy , they take some of the stuff in there backpack.

Chuck.
PS. Jack is right , they are nothing but wood , epoxy and fiberglass so any mistakes are easy to correct.

Oldsparkey wrote:... PS. Jack is right , they are nothing but wood , epoxy and fiberglass so any mistakes are easy to correct.

Except ONE notable mistake. I won't name any names, but his initials are Old Spare Key.

Tim;
Check the link below to the MAS Epoxy website, scroll down to number 5, "MAS Epoxy Cure Schedule". They give a comparison for "Pot life/thin film set/Full cure" for their slow, medium and fast hardeners at different temperatures. Some good info elsewhere on their site.

http://www.masepoxies.com/mas8.htm

One thing they dont recommend is using the slow hardener at 50 degrees F or below. I believe that is common between most epoxy manufactures. Even with the fast at that temp you have days until a full cure.

I am in Florida and I have always used just the slow hardener. Some people only use the fast. Personal preference. But I never have to worry about having enough of one type to finish up. It is 58 degrees (and dropping) here right now, I just applied the cloth patches to some of my hull panels in the closed garage, I put a electric oil-filled radiator type heater under the table. That can locally heat the patch area and get it up to about upper 70's easy, I can drape a cloth over the area (tenting) and heat it a little more, if I had to. I will heat for a few hours and then just turn the heater off while the epoxy is still tacky.

Rising temps during epoxy work can cause some out gassing of the air in the plywood and cause small bubbles, mostly happens on a cut edge. But in the 70-80 degree area I havent seen it happen. Have seen it outside in the sunlight in the 90 degree and rising range.

DM

When epoxy saturating a boat , it is best to do it in the later afternoon as the temperature is cooling down. The air in the wood expands as the wood warms up and this expansion is what causes the bubbles in the epoxy. It works just the reverse if the air in the wood is cooling or contracting.

If you epoxy saturate the wood in the evening , close the DOOR...... The light will attract bugs and when they land on the epoxy .... Guess What ?????

They are stuck there and you will have a really good bug display board. The kids could use it for show and tell at there school.

Chuck.