Kara Hummer Questions?

T

Tom Riegel

Member
Hey Folks,

Yes I am a newbee...Have been searching this site for some time now, looking into building a sneak/layout boat and through all the great threads and mounds of advice decided to 1) finally build a Kara Hummer and 2) join the site. I have decided to do some modifications to Rob's original plans, mainly add a rear transom for a mud motor (which is my next projet). I am eliminating the rear nosepiece and adding a complete transom. What I am wondering is whether or not 2 pieces of 3/4 plywood is what I will need in order to mount the motor? I helped a buddy of mine build the Gator duck hunter boat and couldn't remember if we used 3/4" for both pieces or 3/4" and 1/2". Also, I'm little confused on the keel and deck joists. It sounds like what you are suppose to do is bend the keel down to the nose piece, then take a straight edge and mark on the keel from the deck support to the nose piece the angle. If this is correct, my only concern is that you are thining the keel down, making it a weak point and eliminating wood that is needed to secure the deck. Or, do you just transfer the angle from the end of the keel where it meets the nose piece? As can you see, I am just a bit confused about this procedure. Thanks for any help and it's great to finally get to contribute to another great board....

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The keel(s) is on the bottom of the boat and do not attach to the bow piece. I think you are asking about the side pieces or gunnels that run the length of the boat.

In the plans and various photos of the boat builds you will see that the bow piece has been inlet on both sides to allow for the thickness of the side piece. You are not supposed to thin them down.

For the KARA Hummer all the cuts are full thickness of what ever piece of wood you are cutting the notch for.

Do you have a set of plans yet? The method for cutting and securing all the parts was pretty clear in my plans. Once you epoxy down the deck and nail/screw it the whole thing is pretty strong.

For the transom the two pieces of 3/4 plywood with an angled piece (or two) supporting the joint between the upright and the deck would be the way to do it.
 
Tom,
if you are going to modify the transom of the KARA, be careful! If you place the transom right at the back end of the cockpit and don't raise up the cockpit combing, you may sink the boat with your weight and a mud motor sitting back there. The rear nose provides a lot of displacement towards the rear end of the boat and also knocks down incoming waves. I made a boat with this type of modification, but after a buddy and I were looking at it sitting in the garage, decided to raise the back end of the cockpit combing ~ 4". I'm glad we did as it helps provide some extra free board when making turns or the dog decides to move to the back of the boat :)

We used that boat to build all glass boats from, so I can't help you with the thickness of your transom.

Have fun, it's a great boat to build!

Scott
 
I second what Ray and Scott said

Be sure to put some thought into your transom design. It took me about as long to think about it, shop for the right hardware, and make it, as it did to build the entire boat! I only cut the nosepiece a bit and used a 2 inch thick piece of board for my transom. I cut it out to match the size of the electric trolling motor I was going to use on it. I fiberglassed it separately (like wrapping a gift) to give it strength and used 6 inch long deck screws and a triangular metal brace similar to what Ray suggests.

Can't wait to see pics!

Anthony
 
We used that boat to build all glass boats from, so I can't help you with the thickness of your transom.
Click to expand...
Tell me more about the one off glass boats...photos...weight..etc...
 
Tom,
I think you have the right idea with the keel and the top center support. They are a tapered cut that is screwed down to the nose piece. It is not a strength issue.
I dont have any motor on mine so I cant offer too much help with that. The boat was designed to be polled. It works but not easy for long trips with a double paddle.
Trolling motor gets it pretty far on a battery.
Mud motor goes faster and better in weeds, but requires good boat handling and some common sense.
Make the transom good and strong to support the twisting loads.
I dont know if Ed Askew has re loaded his page of modifications. He showed a set up like you want I believe.
 
Thanks Folks!

Ray, I am actually asking about the keel and not the gunnels. I have the plans and have already cut out the nose piece, gunnels, keel, ribs and have assembled the cockpit. I actually made an error in my beginning thread, the keel is bent down from the 40" rib not the deck support, to the underside of the nose piece, where it is attached. I think what Rob is stating and from what the design pics show is bending the keel down to the underside of the nose piece and then taking a straight edge and marking the angle on the underside of the keel to remove wood so that the hull sheathing will lay flat on the nose piece. I hope I have clarified what I was asking.

Another thing I didn't mention was that the transom will be set back about 38" from the cockpit and instead of using a 40" rib at the rear, I am widening it to 42" and this will carry all the way back to the transom. Hopefully this will create more surface at the rear to support the motor and help with tracking. At the transom I'll attach another deck support to carry the curvature of the deck and attach the decking to that. Of course, the transom will be wide enough so that the gunnels will be attached into a knotch, like the keel knotch in the ribs. I will also angle the transom about 10 degrees back. I think this will work. If you see something that design wise may cause problems don't hesitate to speak up. Then as others have mentioned take another 3/4" piece of plywood and attach it on the backside of the transom for the mud motor. I like the idea of actually wrapping the extra piece of plywood and fiberglassing it and then attaching it to the transom. Makes total sense.... Keep 'em coming folks. I am in no way a boat designer or an engineer but am quite a craftsman...
 
Tom,
It sounds like you've thought it out pretty well. I would slightly taper the transom to give the boat a bit of a reduction in drag. Not a lot, but a couple inches on each side. It will give it a better appearance as well IMHO.




Ray,
Not to hijack Tom's thread, I'll give a brief summary and if you want to learn more we can start a new thread :) About 11 years ago my friend Ben Gallup (from Missouri) showed me how to do this. You can take a boat and use it as a plug. Basically you build a two part mold around the boat. You do the bottom half, then pop that off the boat, then the top half and pop it off. Now, you have two molds, one for each half of the boat. You can cast boats in two parts and then glue the halves together and voila, you have a boat. We've made about 9 boats off the molds over the years. (I don't know the cost per boat today, but it was ~250-300 10 years ago).

My design was based liberally on the KARA (so is the 4-Rivers big boat and even Ira's boats have similar dimensions, shape and characteristics...we all started out hunting with the same people in the same areas in Missouri though I was several years behind those guys). Weight of my boats is about 80 lbs. Yep, the bottom flexes when you run a motor on it, but that's the price you pay for a lighter glass boat. Here is a picture of the original boat being built and my boat when we were heading out to try it out for the first time. I'm also including a picture of the IB duck boat which was Ira and Ben's original design. It's the same length, but much narrower and weighs in around 50 lbs. It isn't nearly as stable as the bigger boats. However, it hides unbelievably well. It can slide in between corn rows and just push them outward a little bit.

My Boat:
View attachment boatontrailerrearqtrsmall.jpg

Under construction:
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the IB Boat before being glued together.
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I had to go look at the mellow collins build thread to figure out what you were talking about.

I had forgotten that the plans call for a piece running down the middle of the boat to fasten the sheething to. When you say keel I consider those to be on the outside of the hull and not the inside.

When you force the plywood to bend over the last rib and flex down to the bow piece you will need to have that piece mated to the underside curve of the plywood. One way to do that is to install the center piece and then take a strip of plywood and temporarily fasten it to the last rib off set from center piece. You can then bend the plywood strip along the center piece and mark the amount of curve you need to remove. Take a hand plane or belt sander and take the center piece down to your mark. Any un eveness will be fixed with thickened epoxy.
 
Scott,
Man, I wish I would have seen your boat 1st, awsome boat design... When you are talking about tapering the transom are you talking about actually tapering from the sides to the midle or to the bottom of the transom: from gunnels to 2"s to the bottom of the outer sides of the transom. I am planning to still use the curvature of the underside on the ends like the ribs. The other addition I was thinking of making, is adding a center runner from end to end. I know, added weight but better maneuverability. But, if the tapering of the transom will elliminate the need for a center runner then I will look at that option. Once again, awsome boat...I likey..
 
Tom, I am in the process of glassing my first modified Kara. What they are telling you to do with the keel is to bend it down to the nose piece and then mark off, for removal, the wedge of wood on the keel that will allow it to mate with the nose piece. This will eliminate excess wood in this area before trying to attach the plywood. As far as the stern, I have also modified my Kara to make it a flat stern. I believe they call it an Atomic Nutria and you can Google this name and find a great website that shows the many stages of building. Two pieces of 3/4 inch plywood might be too much. Obviously it depends on what you are trying to put on back there. I will be running an electric motor and have about an inch of wood built up and am figuring that once it is glassed it should be more than enough strength. Feel free to contact me for any details I can help you with. dc
 
Tom,
Thanks. I'd built 2 Hummers and the IB boat prior to building that boat, so I had a lot of ideas about what I wanted going into that project.

As you asked, there are two dimensions (left to right and top to bottom)

I was talking left to right, letting the boat narrow a bit as it approaches the transom. It's not mandatory, but I think it makes it look better and also helps reduce drag a bit (though that flat transom still sucks when poling/paddling)

as for the top to bottom, I absolutely agree that you should have the bottom curve upward as it approaches the transom (called rocker). This will help lift the bow of the boat as you apply power with the motor and keep the boat from nosing into waves. Head on, I can take some pretty decent waves if necessary (though I really don't want to).

For maneuverability, do you mean tracking or turning? Mostly the runners are there for protection and several people have said it helps with tracking while paddling. I've always added them for protection because some of the areas I hunt include dragging the boats over levees and I carry the boat on a flatbed trailer so it helps protect the bottom of the boat. I can't compare it as far as tracking is concerned since I've always had them on my boats. Two runners has worked great on my setup with a small outboard motor and for poling. If you meant for faster turning, all I can say is don't :) That outside deck WILL dig in if you try and turn at any speed at all and you'll get wet. I've had water up within 1" of the top of the combing and don't want to be there again. SLOOOOW steady turns when motoring a piece of plywood in the dark in December :)

Enjoy your build and be sure to share pictures of it so those of us having withdrawal can enjoy it!

Scott
 
Dave,
Thanks! I finally figured it out.....small brain...Anyway, I have seen the Atomic Nutria and had thought about going that direction but since I am going to eventually put a 65-85 lb. mud motor on the back of it, I was thinking that I would need to beef the transom up and widen the hull to not only handle the load but the torque. I may also use a trolling motor but should be able to rig something up for that, with the beefed up transom. If I run into anything (which I usually do) while building I'll definitely contact you... I haven't ever fiberglassed before so when I get to that stage I am sure I will have plenty of questions. Hey-Thanks for the help....I need all I can get... Tom
 
Tom, I am a fiberglass irgin myself. I glassed across the seams last night on the bottom. I will sand them tonight and get ready to glass the bottom this weekend. I will put two layers of glass on the bottom and one on the top. I have a friend coming down this weekend to help mix it as we go. I am hoping everything goes well. Just holler if you have any questions. dc
 
Dave,

Man, I wish I was close to you, because I would definitely give you a hand. Fortunately, My good bud Scott will give me a hand with the glassing of my Hummer but I'll have to work around his crazy schedule as a trainer for Special Forces. We built him the Gator Duck Hunter but he opted out of glassing...wasn't my idea. We are currently in the planning of building him an 18' duck boat based on the Duck Hunter but modifying it up deck to handle rougher seas. Eventually, I am going to build the same boat (shhhhh! don't tell the wife), This time we are going to glass this boat. Tom
 
Scott,

I gotchya.... Thank goodness the piece of yellow pine I ripped the gunnels and keel out of, naturally curves up both bow to stern so this should be a pretty easy feat, lifting both the bow and stern. I'll opt out on adding the center runner and just attach the recommended 2 runners with the added attached aluminum for protection. Thanks for pointing that out to me. I have figured out this isn't a "scull" hull and turning will be slow and deliberate. I just have to keep reminding myself of this...

Yes, I'll definitely add some pics as I progress. As someone else here said, "this boat building is addictive". But, it's much better than being addicted to drugs or alcohol and my wifey knows where I am...hahahaha!!! That's what I keep telling her... I just can't tell if it's working.... she keeps comparing it to my afflication to buying fine firearms, which in my defense has slowed down considerably..

Tom
 
Just a quick Thanks! to all who answered my questions. I have the frame assembled and am waiting for the epoxy so I can epoxy the frame to retard water rot. Total hours so far are about 20...a good bit of that spent on figuring out my modification. The actual assembly has been relatively simple. I pretty much did it all from memory after reading the instructions a few times.

Now for the sheathing and then the fiberglassing. Once again, I am going to take it slow. I hate waisting material...As the need arises I can guarantee I'll be asking more questions and I definitely won't hesitate to ask the members here. You Folks are great! I'll try and get some pics up of the frame in the next couple of days. My wife is at a conference in the big apple and she took the digital camera with her. I may try and see if my teenager will let me use the one I bought her but she is a teenager....

Tom
 
Ok,
I have actually been working on my modified hummer for a couple of weeks now and am having a blast. Frame done and bottom added. Next, resin the frame and inside-then adding the top skin. Can't wait..... Went ahead and addeda few pics so you folks can see my transom mod. and my progress. ThanKs All! For all of your help. Tom R.
 
IT LOOKS ALL WRONG! Hahahahaha, just kidding! Tom, it's coming along great......only 5000 more hours and plenty of head scratching over different options and ideas. Hahahahah! Have you bought the paint and stencils yet? dc
 
Dave,

Thanks! I was beginning to panic...What did I do wrong...! Nope haven't gotten the paint yet. Here I live on the coast, with tons of recreational boats all around and not one of the marinas is carrying Parker duck boat paint.... Go figure! It looks like I'll have to find, once again, another supplier on line.

Thanks Again for all of your help.... Hey, I just looked at a photo of yours in your paint thread and it looked like you used 2x6s for all of your ribs. Is this true or just a pigment of my imagination???? Man, if you did I may have to build me another one since I used 1x6s....mainly, to lighten her but now I could see that this would increase the weight but you do have the advantage of putting more weight in her... This boat buildin' stuff is a freakin' addiction!!!! Oh, I hope you don't mind but I am going to steal your idea for the double gun racks....2 racks are better than one...LOL..
 
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