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Catspaw 8 #799

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Hey everyone! I'm getting started on a Catspaw 8. So far everything is going pretty smoothly, but a couple of questions have come up about the transoms and I thought I'd throw them out here on the forum.


I've glued the stiffeners to the transoms, and I'm at the point where I need to bevel the port and starboard ends of the stiffeners to match the angle of the sides. My question: Should I also bevel the edge of the plywood, so that the stiffener and the plywood edge make one continuous plane? Or do I bevel just the stiffener, so that the side will contact the beveled stiffener and then the outboard corner of the plywood, with a little triangular gap in between the two?


Second, I'm having a little trouble deciphering the plan diagrams that show the framing for the stern seat. My interpretation is that the 1 1/2" x 3/4" piece of seat framing that attaches to the stern transom goes below the transom stiffener (i.e. so it's attached to the plywood, not the stiffener). Then it has a shallow U-shaped notch cut in it so that can overlap the filler piece and the outboard pad. That was hard to explain, and probably hard to understand, but does it sound like I'm on the right track?


Thanks for the advice!

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Hi Ben,


You do not need to bevel the ply. We prefer leaving that gap so that it will fill with epoxy when you lay in your fillet. The bevel for cutting the stiffeners can be taken from the quarter knees. Most people do not even bother with beveling the stiffeners just filling the gap with thickened epoxy. I like to bevel them but if you get it wrong and have too much bevel you will have to trim it off which can be difficult because it is across the grain. I find that a mini grinder with a sanding disc will allow you to trim it easily. On the same note; when you screw the sides to the transom stiffener, you need to just draw in the screw until the sides just touch the transom. If you tighten the screw it will pull in a fish tail when viewed from above.


I need to look at that plan to be sure that I give correct advise because there have been some options, the way I intended it was as you interpreted it. The 1 x 2 should be fitted round the vertical reinforcing. Because the transom rakes, you need to bevel the top edge of the 1 x 2 so that the ply top will sit flat.

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10 hours ago, Designer said:

The bevel for cutting the stiffeners can be taken from the quarter knees.

I thought I was all set, but this line threw in a new complication. The specified angle for the stern stiffener matches up perfectly with the aft quarter knee, but the forward one does not. Which one should I follow?


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The angle between the sheer and the top of the bow transom is approximately 115 deg. That would be the angle of the forward quarter knee (or very close to it). The bevel angle of the stiffener on the bow transom will not be this angle because the bow transom has a lot of rake compared to the stern transom. Measuring the angle at 90 degrees to where the side and bow transom come together (shown with a disk below) is much closer to the given angle of 127 deg. I can see how that would be confusing but that is the angle you would set your bevel gauge to in order to cut a bevel on the end of the bow transom stiffener.  Let me know if that make sense. 








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Overthinking things again on a weekend morning...The plans don't call for sheathing the hull in glass. If the plans don't call for it, then I'm sure it's not necessary, but I see that some other people have chosen to do it anyways (one example). What are the pros/cons of doing it vs. not doing it?


I'm going to be using this to row out to my boat on its mooring. It'll get stored on dry land, so there'll be a little bit of hauling it in and out of the water, but no really rough treatment.

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Correct, not necessary for strength. If you want the lightest boat possible then don't sheath in glass just tape the seams. Every ounce counts on a small tender. It'll make it easier to carry and haul on board. That is what I personally would do. On a small boat it's easy to do little repairs to the bottom if it gets scratched or dinged. You can just flip it over, do the repair and your good to go. 

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  • 3 weeks later...

I've got the inside taped up and coated in epoxy, so I'm ready to flip her over and start on the exterior.


Looking ahead, I have a small question about the gunnel. The instructions say something about making sure the gunnel is applied 1/16" from the top the of the sides, but I'm unsure as to whether that means 1/16" above, or below the top of the sides. Above makes sense to me, since then I'd have a little meat on the gunnels and could bring that down to match the sides. Is that right?


Oh, also, I'm not supposed to glass the outside of the center seam, right? The bedding of the keel gives enough strength for this joint?



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Ben, your boat is looking good.


The gunwales give the top half of an open boat lots of strength. Another function is to give the top of the boat a finished look as it defines the sheer line. The reason that I stand the gunwales above the sides at the ends of the boat is twofold, it is more aesthetically pleasing if the gunwales are tapered slightly at the ends. You will notice that the sides have more flare at the ends, especially at the bow. If the top edge of your gunwale is 90 degrees to the sides which is normal, the top outboard edge continues to angle down below the plane of the bow transom as it goes forward. I like the knees to follow the camber of the transoms and the gunwales top edge to follow the camber of the transoms. After installation, it is easy to dress off the top with a plane using the bow and stern transoms as a reference to get the angle just right. I dress off the transom beam tops to the gunwales at the same time. I always enjoy this part as it really brings the boat to life. 


At the stern transom centerline I leave the top edge square which matches an outboard bracket if I will be using one. From the outboard pad I plane a twist as I work out to the quarter knee


You must glass the keel line on the outside. Plane a 3/4" wide flat the whole length of the keel before glassing so that you will have a landing for the keel. To keep the flat horizontal, I monitor the flat as I go by setting my plane centered across the flat, I can see if the gap is larger at one end and then plane a bit more on the appropriate side to keep the flat horizontal. You may be more comfortable using a small level as a guide but make sure that it is square to the boat when checking.



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  • 3 months later...

Still plugging away on my Catspaw, although my dreams of launching her this summer have…sailed.


Right now I’m assembling the center seat and I’m wondering, is there any reason not to affix the pieces together with fillets rather than the 3/4 x 3/4 rails called for in the plans? I have it all tacked together with epoxy and at this point it seems easier to go the fillet route rather than fitting and shaping filler rails.



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I can't really tell you which is better; I did mine as per the plans and it did work well.


One thing that might be specific to my use though: I spent about five months this year in a boat-access only place and commuting to work, I used my Catspaw to get out to the mooring where I kept my big boat.


What I found was that every morning and evening, when I picked up the Catspaw to carry it up or down the beach, I ended up picking it up by the centre seat and by September I was starting to hear little pops and cracks when I'd pick it up.


So depending on my workload over the winter, I would personally be inclined to replace the cleats with fillets, but then run fibreglass tape over each one.


BUT: I think my boat has had harder use than the vast majority ever will, getting rowed and picked up and set down every day, sailed on the weekends, and left floating in the bay ten hours a day from Monday to Friday.  Making me question the decidion to finish it all fancy-like, of course, but when I built it I didn't realize I'd be moving to my cabin for half the year and working on a different island.

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  • 3 weeks later...

Progress over the summer was slow, but I'm picking up the pace again, and it's looking more and more like a boat. I've had a couple of setbacks, the most recent one was when I epoxied the side of the centerboard trunk on the wrong side of central spine of the seat. :rolleyes: Had to cut it off, fill the scars, and rebuild it, but I'm almost back to where I was.



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On 10/18/2019 at 9:04 AM, Steve W said:

For me, a lot of building is thinking to avoid mistakes and then thinking about how to fix the ones you made anyway.

This is very true to my experience.


Speaking of thinking, I decided (since there's no worry any more about trying to get the boat in the water this season) to beef up the central frame with some additional joinery, rather than relying entirely on gussets. I went with bridle joints at the ends and an odd-shaped half-lap in the middle:



I'm going to add gussets to the side joints, but I'm planning (for now) on leaving the middle joint gusset-less, since it's also going to get epoxied to the centerboard trunk, which I figure will give it sufficient support.



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  • 4 weeks later...

Ok, the frame is almost ready to go in, along with the central seat. Any tips for how I can align the seat properly with the keel? I’m thinking of epoxying it down first and then cutting the centerboard slot later, but I want to make sure everything winds up in the right spot.


Second question: what’s a good way go about cutting out the limber holes that pass through the seat and frame? Do one first (probably the seat) and then trace onto the frame. That’s what’s making the most sense to me, at the moment.


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