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Hybrid NL - semi V modification

12K views 43 replies 9 participants last post by  sharris 
#1 ·
I built my first 8' hybrid NL last year. I like projects and after building it I figured I could change the design a bit to better suit me. Long story short I sold my boat and got most of the money back that I spent on building it (down about $50 from build cost) and ordered supplies to build another one.

There were a few things I didn't like about my first hybrid that I want to change on this one.
1. I don't like how it tracks, but that is what the trade off is for the stability. I think making a semi V shape in the front shouldn't take away much stability and should make it a lot easier to paddle. I am working on an idea right now and we'll see how it goes.

2. I really hated the water that my dog brought in when she climbed into the boat. For this one I am going to put on pods and put a dog platform on the pods so the water drains out of the boat into the lake.

3. I am going to modify my fiberglass techniques and see if I can get the build time lower and epoxy waste lowered.

4. I have been wondering if I can do away with the front frame to make the internal fiberglassing go easier and decrease the boat's weight. I have some ideas about how to do this.

Here are pics from day 1:
-Sketch out the general shape that I want on thin luan plywood. I think the arch may be too steep towards the tip and my angles might need to be changed on the sides. I'll play with it and maybe cut off 6-8" from the front before I glue it.


-Insulation foam makes a great underlayment for cutting when using a circular saw. The wood doesn't move and when I'm done I can cut the foam up for flotation in the pods.


If anyone has tried this design modification and has suggestions, let me know. This is going to be a very slow build, but I'll post pictures periodically as I go.
 
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#3 ·
It works. ONE other guy (AR34 on the "other forum") did it came out nice - I keep threatening but haven't gone there yet. You are doing it correctly.

As for glassing the inside - stitch up the boat - do your epoxy glue and don't glue the Frame/bulkhead in. Pull the bulkhead out, glass the hull, then put the bulkhead back in while everything is still gooey - glue and tape it in. I do that on the Prototypes and it works well.

Some other boats use wood sticks up the sides and across the top - you could work something like that instead of the bulkhead. Just remember that you get a lot of structural strength at that location - it supports the bend of the bow, the sides, the bottom, the top deck, and now in your case, it will help support the V.

I'd put a layer of tape or heavier cloth down the V and an extra layer on the outside - as much to help strengthen as to protect from wear.

Haven't been building much due to overworking myself. Thanks for taking the build to the "next level" - that's what makes it worthwhile for me - to see someone improving on the design. Keep us posted! :thumbsup:
 
#5 ·
MissedAgain said:
It works. ONE other guy (AR34 on the "other forum") did it came out nice - I keep threatening but haven't gone there yet. You are doing it correctly.

As for glassing the inside - stitch up the boat - do your epoxy glue and don't glue the Frame/bulkhead in. Pull the bulkhead out, glass the hull, then put the bulkhead back in while everything is still gooey - glue and tape it in. I do that on the Prototypes and it works well.

Some other boats use wood sticks up the sides and across the top - you could work something like that instead of the bulkhead. Just remember that you get a lot of structural strength at that location - it supports the bend of the bow, the sides, the bottom, the top deck, and now in your case, it will help support the V.

I'd put a layer of tape or heavier cloth down the V and an extra layer on the outside - as much to help strengthen as to protect from wear.

Haven't been building much due to overworking myself. Thanks for taking the build to the "next level" - that's what makes it worthwhile for me - to see someone improving on the design. Keep us posted! :thumbsup:
Thanks Missed. Here is the issue with the front frame/bulkhead. If you look at this image, I put in an arrow that shows where the center cut extends to (20" beyond curve). This allows there to be a much gentler transition from the V shape in the front to the flat shape in the back. If I put in the front frame at the normal spot I have to determine exactly how much of a V shape needs to be cut into the bottom of the frame early on (plus account for the change in width of the bottom at that point). My plan is to stich and glue the bottom V-shape together and after it's complete put together a temporary frame to hold the sides in place while I epoxy the sides to the bottom. The temporary frame is going to be 2X4's and they will be above the seam between the side and bottom, so that I can run the fiberglass tape without interruption. For fiberglassing I am skipping using construction adhesive and instead will put down a little epoxy and before it is fully cured put down a fillet of epoxy/talcom mix and put the tape on top of that. If I put it down wet I should get a smooth seam between the side and bottom without having to do any sanding.

Just like in my last boat build I am putting the tape down first and then putting the cloth over the top. I previously did it for cosmetic reasons, but this time I am doing it that way to make glassing the inside of the boat quicker and easier since the tape will hold the boat in shape and then with the frame/bulkhead out it will be a lot easier to glass the inside.

I am taking a break for about 1.5-2 weeks to work on other projects, but will then start glueing the bottom into the V-shape.

 
#6 ·
Sounds good to me. :beer:

I have limited epoxy experience with the cabosil/aerosil/silica powder and found it to work great as glue - I've used it wet under the tape & cloth just as you mentioned - works great. You can mix it like peanut butter or you can use it "looser". I found that when I mixed it in a zip lock & tried to use it like a frosting tool (cut the corner & squeeze), it left too much mix in the bag for my liking. I mix it in a bowl and am happier not loosing so much material. Anyway, I would spread it in the seams and then use a plastic spoon or epoxy-saturated paint brush to smooth.

Keep us up to date.
 
#8 ·
mudpack said:
Great tip on the foam pad beneath....but how do you cut those curved lines with a circular saw?? :huh:
It's really easy. As long as the blade is adjusted just beyond the thickness of the wood it cuts curves just fine (plus it's a lot quicker than a hand saw or a jig saw).If the blade is adjusted too deep then cutting curves doesn't work. Also use a higher tooth count -- I think this is a 40 tooth blade.
 
#9 ·
Quick update. I've been busy with travel and visitors but finally got a chance to glue the V-shape in the front. This basically just shows my fiberglass technique I am going to use for the whole boat.

Top view - Zip tied into shape.


Front view - blue painters tape so the epoxy doesn't run


Epoxy technique step 1: I am using 3" tape so I put a line at 2". I then add resin to the wood (this makes it a lot easier to put the tape down) and put a mixture of resin/filler at the joint. This combo has a peanut butter consistency.


Epoxy technique step 2: Add 2 layers of overlapping fiberglass tape. Paint epoxy on tape until it is saturated.


Ready to dry: Using this technique I get a smooth joint with no air bubbles. It is far stronger than the wood. A toothbrush works really well to put down epoxy for the tape. Hopefully I get some time in the next week or two to put on the back and sides. The very front will be cut off when I put on the sides so I left a little gap.
 
#10 ·
I v the bow on all mine, It works very well and looks like you have the lines lofted good. Be careful using the luan as most of it has interior grade glue and will delaminate if/when it gets wet. Ply used should have exterior rated glue. Also it looks like your using micro ballons for filler, they are typically used for fairing the surface. They don't make a structural filler. Structural fillers would be a better idea, silica and wood flour or fibers, or even just silica would be much stronger.
Just some tips...
 
#12 ·
Lane said:
I v the bow on all mine, It works very well and looks like you have the lines lofted good. Be careful using the luan as most of it has interior grade glue and will delaminate if/when it gets wet. Ply used should have exterior rated glue. Also it looks like your using micro ballons for filler, they are typically used for fairing the surface. They don't make a structural filler. Structural fillers would be a better idea, silica and wood flour or fibers, or even just silica would be much stronger.
Just some tips...
Thanks for the tips. All of your points sound correct to me. However, for the size/strength/planned usage of this boat I can't imagine that there will be any noticeable ill effects. I am using luan and the inside and outside will be covered in fiberglass cloth to prevent water damage. I did use a fairing compound for the filler. I was intending to use talcum powder but misplaced the container and used what I had on-hand until I get to the store to buy more. I'll fill with talcum powder on the outside of the V when I tape it up. By the way, I read that the fairing compound has about 50% of the strength but it is also used in race boats for fillets due to the lighter weight so it should be plenty strong for a hybrid.

Since you've made the V bow before I have a question about the sides of the boat. Did you have to taper the sides towards the bow?
 
#14 ·
Sharris,
I agree you probably will not have any problems, as long as you store the boat someplace dry when not in use. Even epoxy, will allow a bit of water vapor thru and tho wood will not get wet, its moisture content will rise. That said I have a couple year old prototype that has luan topsides and even in my damp climate, has not delaminated....but I do store it in heated shop when not using. For filler, Ive not heard of anyone using ballons for fillets as fillets are typically structural, but hey if its worked for someone... probably will work fine for you. Talc, or even baby powder works, I use a lot of saw dust I sweep off the floor....
For your sides, what I do , the sides basically become pointed. I bring them to a point at the bow and then all the lines come together very nice. I will look for some pictures, don't have one under construction right now as have been working on a 24' cabin boat last couple months, but may have some pics.
 
#15 ·
These little boats look pretty darn cool. :beer:

I have a couple of questions:
-are they all made of 1/4" plywood, and some 1x4" pine boards?
-What oz fiberglass are yall using and how much epoxy does it normally take (quart, 1/2 gallon, gallon).

I have no problem buying the plans from the guy just trying to figure out the options. I've built smaller boats for a friend's dog to lounge in the pool with us using stich and glue so this just looks like a blown up version.

I'm definatly following this thread closely.

Thanks,

Tod
 
#17 ·
Thanks Lane! That picture helps a lot. I figured I would have to modify the front a little from the stock plans. Your work looks great.

Tod - Any plywood width works, but since the strength is from the fiberglass most people choose thin plywood to keep weight down. I use 6 oz fiberglass cloth and I think my tape is 8 or 9 oz tape (I can't remember since I bought it off ebay). My last hybrid took 2.5 gallons of resin but I wasted a lot since it was my first time working with it.
 
#20 ·
Hi Missed - Last weekend I cut out the transom and the bulkhead but a storm was predicted so I didn't glue anything together. I'd like to glue them in and attach the sides this weekend, but am questioning whether the weather will cooperate.
 
#22 ·
I finally had a little free time to work on the boat.

-Here is a pic of how I modified the sides. On a later picture you'll see that the outside curve probably should have been a straight line instead of a curve. I'll saw it straight before putting on the top.


-The sides are on and it is braced into place.


-I "spot welded" the sides in place with epoxy mixed with fairing compound along the outside. This let me remove the bracing and zip ties so I could tape the inside seams without obstructions. Those will get sanded off when I fiberglass the outer hull. I did it this way because it is a lot easier to sand outside the hull than inside.


-Seams taped and roughed with sandpaper.


-Fiberglassing (definitely not a professional job when you look up close at all the runs/drips, but it will suffice)


-This shows the profile after I cut off the extra wood. The front is narrower than a normal hybrid NL. Also, the boat is now at 7 ft long for the cockpit. If I wanted it longer I would have moved the transom farther back, but this should do it for me since I am going to put my dog area behind the cockpit and still have a couple feet of wood to play with back there.


-Interior view
 
#23 ·
Looking good. I'm not one to tell anyone their business but if it was mine at the place you have it.... I would cut a gage block to match the height of the sides at your rear bulkhead. Then use that to make a pencil mark around the ext of the boat and keep everything kinda straight and level. I think you will find your sides will transition into the bottom back from the bow and you'll be cutting a little more at the bow section as well. Otherwise you will probably wind up with the illusion of running bow high even empty and youll have more chance of casting odd shadows that make the bow stand out while your trying to hide.
 
#24 ·
Thanks for the suggestions Lane. I was planning on cutting the bow a little (you can see in the second to last picture that the sides curve up in a rainbow shape right before the bow tip). I'm not sure how much I am going to cut off yet. It might just be from the front frame to the bow, but I'll do some measurements first and then decide. I'm OK with the bow being a little high since that is how the flat bottom hybrid NL's come out.

What plans did you use for your boat? I might want to try something a bit more detailed one day instead of just "winging it" as I have been doing. I bought a 50 yard role of cloth so I still have supplies I can play with in the future.
 
#25 ·
My boats are my own design. I originally had big plans of getting a good design and then making plans avail for others. But while searching for surface drive motors small enough to power a layout, I came acrossed MissedAgain's build thread and plans. Not wanting to take away from his effort, I'll not offer plans, just offer assistance. I normally build much larger craft than layouts. The layouts are just a lot of fun to build cause they don't take forever.
 

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#26 ·
I'm going to cut my boat to make it shorter in the front. I am actually building two boats right now (one for a buddy) and his boat is getting the modifications that I am learning through experience. With his we moved the whole frame further back in relationship to the bottom to keep the front lower. The obvious tradeoff is that there is less of a V in the front.



 
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