For builders needing to buy a saw, you can’t go wrong with a high quality saw like the Porter Cable (see the links at left.) This one comes with the blade either on the left or right hand side. For ripping the stringers, and other ripping operations, make sure the saw you buy has a rip guide available, also shown at the left. The rip guide for the Porter Cable saw is about $14, and well worth the cost.
Sometimes you’ll see cheap circular saws available, and if your boat is about the only time you’ll use the saw, they will probably work OK.
The Hatachi shown at left is about the cheapest you’ll find in places like Amazon.com’s Tool Crib, at $110, but I didn’t see a rip guide for it. And, I have to be honest, for the $20 difference, I would go with the nicer Porter Cable saw (in fact, I did, and love it!) Sometimes you can find Skill or Black and Decker homeowner saws for under $50 at Lowes or Home Depot ... a good buy. They aren’t as durable and nice, but if you only need them for building a Weekender, they’ll do fine.
The Blade
The blade can make all the difference. Most saws, especially the cheap ones, come with lousy blades. You
can spend over $100 on a blade, but great thin kerf, carbide tipped blades can be found for under $20, and make a
world of difference when making curved and plunge cuts on your boat. You might be tempted to buy a more expensive
"plywood" or "veneer" blade, but a thin kerf, "combination" blade is the most useful. You don’t have to change
blades to quickly saw 2 x material, and then change back when cutting the plywood. The blades are not that
expensive; the DeWalt thin kerf we've linked is about $10. The Matsushita blade is about $13 (they also have a
better grade of carbide on one blade, and its about double that.) I’ve used the DeWalt and its cheap cousins,
and they work great. Much better than the plain steel blades that usually come with the saws. The thin kerf
helps in two ways; it eats up less wood, and is easier to push through the stock. And easier to make those
curved cuts when cutting out the keel, bottom and deck panels too.
In the general safety tips area: Leave the safety devices enabled. And then watch for complacency during use. Think through each cut before you make it, keep the area clear so you can make the cut from one end to the other without tripping over things. Watch the cord to make sure it doesn’t hang up while you’re cutting (sometimes the plug will catch on the edge of a long piece of plywood, and without thinking you start to try and force the cut.) And let the saw cut the wood: if you have to force it, something’s wrong, and you may be headed for injury. Stop, release the trigger to stop the saw, look around, and don’t continue until you find the reason the saw is binding.
Kickback can happen when the cutoff can’t
I prefer to work with the material as close to the ground as possible, using 1 x 2’s or 2 x 4’s directly on the ground to support both sides of a long cut. This minimizes binding if I have miscalculated how the kerf will open up, and errors are much easier to react to. If its plywood, and I know I’ll be working my way across it on my knees, I make sure to support the plywood where I’ll be kneeling with an additional 2 x 4 underneath. Blade depth should be set as shallow as possible to cut through the material. Even though I’m a slob, I try to work in a clear area too; make sure you don’t trip, get the cord hung up, or cut something you intended to leave in one piece. Like the cat.
There are a lot of times you can "hurry up," but it isn't when you are using a circular saw. Take your time, and think "safety". If you start to get tired, STOP. An injury just isn't worth it.
Rip CutsFor long straight cuts in plywood, many craftsmen use a straight edge clamped to the stock. First, they mark where the cut should be, then measure the distance from the edge of the shoe to the blade on their saw, then measure back from the original mark on the material that amount. Then they clamp the straight edge to the stock with C-Clamps, double check that they have measured correctly, and cut the stock by guiding the saw along the straight edge. Tool stores sell 8’ long aluminum straight edges specifically for this purpose, but any straight piece of lumber or other material will do, such as extruded aluminum salvaged from sliding glass doors, etc. Or even the edge of another sheet of plywood.
An inexpensive jig can be made that simplifies this. Here’s a quick and dirty one I made years ago. I used a 2 x 6 with a good straight edge, and attached a sheet of 1/8" doorskin plywood to it, making sure that the 2 x 6 was set back from one edge far enough so that I could trim off a bit if I guided the saw along the 2 x 6. Then, I did just that, cutting the doorskin on both sides of the 2 x 6.
The jig is finished. I mark the stock, position the edge of the doorskin at the mark and clamp the jig down. Then I cut the stock by guiding the saw along the 2 x 6 edge. Fast, easy, and I don’t have to remember which of those little marks on the tape measure are the eighths to accurately position the jig. An improvement to this would be to use something other than a 2 x 6, like a 1 x 4, so the motor could ride over it on one side. That would leave a wider base on one side of the jig, which is nice for balance.
When cutting the front hatch opening, a plunge cut is used, and unlike with other cuts, you have to hold the blade guard in the up position while starting the cut. Here’s the correct procedure to remain safe: Mark the cut lines clearly on the deck. Drive a large screw into the center of the piece being cut out. Adjust the blade so that it will barely cut through the 3/8" deck plywood. Begin near one corner and place the front edge of the saw base firmly on the wood, lift up the blade guard and line up the blade with the marked line. Make sure the blade is just above the plywood, and not touching it. Start the saw, and slowly lower it into the plywood. When the entire base is flat on the wood, you have cut through. Move the saw slowly, following the marked line, until you are about ¼" from the corner. Don’t move the saw backward with the blade spinning, as the rotation of the blade can make the saw climb out of the kerf. Turn off the saw, and remove it from the cut. Position the saw to saw the other direction on the same line, and cut to a ¼" from the corner. Repeat for the other three marked lines. Because the corners have not been cut through, the waste won’t twist and fall, binding the blade, making the saw jump back at you and injuring you. Use a hand saw or jig saw to cut the corners cleanly. Hold on to the screw in the center while using the hand saw to prevent the waste piece from twisting loose and tearing the corners out. A Great Little Hand Saw
If you don’t have a fine cut hand saw, I especially like the new "Japanese style" saws for trimming like this; they cut on the pull stroke and are easy to handle. They also make great, smooth cuts in rub rails, etc. I nearly wore my Shark pull saw out … at about $15, they are a great buy over the traditional dove tail saw (at $40 plus.) There are quite a few of these available now, and once you get used to cutting on the pull stroke, you'll love them.
Shark Brand Dowel and Dovetail Pull Saw, About $15
Once I get a tool, I end up using it much more than I ever thought I would. If you don’t have a circular saw now, once you buy one, you’ll wonder how you ever got along without it.