Thread: Nice rowboat, nothing fancy.

I'm using these: http://www.gacooarlocks.com/gaco-oarlock.html

They're the same in principle as the racing type (fixed pin, flat back oars) but without all the fancy adjustments. As long as the pin is set vertical they should be fine.

Just threw the first undercoat at the thing. This is tinted the same colour as the top coats, so gives a good idea of the finished product. I like it. Looks good against the oiled timber.

Second undercoat is on and touch dry, so I flipped the boat onto its trolley and took it outside for a few pix and a bit of pondering.

Naturally this procedure dinged the still-soft undercoat in a couple of places, with the added bonus of also dinging the ever-so-spiffily-sanded-and-oiled Surian cedar sheer clamps in a couple of places. Hmm. Methinks I need a bit more rounding of corners and padding on the trolley chocks. So, that's another little job to sort. I reckon I'll go belt and braces, and round over everything then pad the crap out of it. Given my intermittent propensity for idiocy, having it idiot-proof makes sense.

Anyway, undercoat was going to be sanded and sheer clamps are easily touched up with a bit more oil, so no worries.

Having a good look the whole boat in its current state made my mind up about the interior painting. I was originally thinking of using cream enamel on the inside of the garboards and bottom, but had already decided that wouldn't be all that swish. Then I thought maybe cream garboards, with the bottom in the same colour as the topsides. Looking at it today made things clear, so I'm going to do the garboards the same colour inside and out, and carry that over the chine logs, with the bottom panel itself in cream. This will look cool, and we all know that looking cool is terribly important stuff.

I figure I'll get a bit of fine sand and non-skid part of the bottom too. The plan is to have just plain cream paint the same width as the limber holes each side (roughly 45 mm) and about the same forward and aft of each frame, with the non-skid section inside that border. This will keep things clean along the chine logs and through the limber holes, while still providing enough sanded area to catch feet anywhere on the bottom panel.

Anyway, more pix, just for fun.

Now for the other bit. Getting a good sheer line on a prototype is always a bit tricky. Generally, this one looks very good. However, from some angles the first few feet aft of the stem look just a little bit droopy. Nothing tragic, just not quite spot on.

Naturally, as a long time lover of good sheer lines, this annoys me. It doesn't annoy me too much, just enough to want to fix it on the next one. It's a weird one because the sheer "shouldn't" look droopy there, as far as I can tell from the lines plan and perspective views in Delftship, yet it undoubtedly does anyway. Fixing it without borking something else from some other angle is going to require a bit of thought and study. I have time for that, since I won't be building another one in a big hurry anyway.

Forget the droopy sheer, you gotta look real hard to se it , because its disguised by the rest which looks very kool.

The over all boat looks fantastic, and yes you wont have to build another for some time.
I like the way you have economised with most bits, even the paint.
I'm keen to see how she will handle on the water. I know that you have said that the design is for the most part flatish water, do you think she could handle a few2 ft wavelets.? are you talking really flat water
how are the blades coming on.

Yeah I'm not too worried about it. It's just a detail I'll fix on the lines plan before someone builds another boat to these lines (in case anyone ever does).

The "economising" was simply because I happened to have acquired stuff that would do the job, so it made sense to use it rather than leave it lying around taking up space. It wasn't an attempt to save money as such, it just worked out that way. Where it was necessary to buy the right stuff for the job (like the Deks Olje) I bought it. I think this is probably the way most people approach similar projects. If you have stuff that'll work, you use it. If you need extra stuff, you go and get it.

When I was talking about flat water, I meant I was assuming it would be fairly flat when racing the thing. In rougher conditions I'd pick my speed and path to suit the conditions.

In general terms, this boat should handle much like the Herreshoff/Gardner 17 footer, but directional stability should be better. Any conditions that boat can handle should be fine for this boat. That means anything you're likely to encounter on a large estuary, including 25 knot wind against an ebb tide, should be ok if the person handling the boat knows what they are doing. On the other hand, beginners should stick to calm conditions with minimal current.

Oars are coming along. I did some work on the jig for the blades yesterday, and will finish that today. Hopefully I'll get the blades glued up tonight. I've also marked out the first cuts for the tapers on the shafts.

Alllllllllllll righty then. Having screwed up the first go at making the blade jigs, I have now actually got the silly things (Mk II) sorted.

About halfway through this schemozzle I started thinking I could have just gone ahead and carved the blades from solid. I wanted to try this idea though, once I'd thought of it, so kept going. I figure if it works well it will mean making more blades should be a piece of cake, if I ever want to do that (probably will sometime).

The jigs look like the pictures. I've taped the wedge to the clamping batten, just so the arm the clamp goes on top of will sit level. I think I have headed off as many gremlins as possible, although no doubt more will be lurking somewhere. The blade shown in the pix isn't glued yet. That's the next step, for after lunch. I expect it'll need a few more clamps around the edges, but that's easy enough. Generally it sits very nicely, and having the pressure and curvature applied from the middle should mean the excess glue will naturally want to move to the edges, so it should give good glue lines everywhere, without lumps and/or voids. Fingers crossed.

Ok, so the sticky stuff is on and they're all clamped up. Nothing went wrong. I'm not sure if this means I'm getting smarter, or if they're just biding their time and plotting something dire.

I'll leave all the clamps on until Saturday morning or afternoon, depending on how badly I need the bench space then. I figure the bricks can go tomorrow since they're only to help contact until the glue gets a cure underway. Not having the bricks there will make the work area a bit less precarious, which is always good.

Got the oars blanks roughed out. One of them took a slight vertical curve when I cut the excess wood away, so I'm leaving them overnight to stabilise and will reassess the taper, etc tomorrow.

I'm not too worried about it since the unwanted curve is very slight, and I was thinking I'd laid out the taper so the shafts were a bit too thick towards the blade end anyway. That means I have a bit of meat I can afford to lose if I want to do a bit of straightening.

The blades will come out of the jigs tomorrow too, which is necessary before I do the final shaping of the shafts. I have the process for fitting the blades more or less sorted in my head, but no measurements as such. I'll sort it as I go.

Also, I don't agree with all of Culler's ideas on oars, but I do like his reverse tapered handles. They just seem to fit my paws very nicely. IMO straight or barrel-shaped grips are just not as nice in the hand.

Just pulled the blades out of the jigs. They seem to be fine. Hardly any springback. They basically drop straight back onto the jigs. They are very stiff. Holding a blade in two hands and trying to flex it gets no noticeable result. Ok, that works. I now have compound curved plywood blades.

Threw them in the kitchen scales and they weigh 350 grams each. This will be trimmed slightly by the time they are on the oars, but then they'll require a finish of some kind, so 350 is probably about right for the finished product. This isn't bad. The Gaco oar blades, which are a glass/carbon/Coremat composite, come in at 300 grams per blade for the same blade area, so 350 in boring old wood isn't a bad deal.

There was (of course) one slight glitch. When I was sighting the blades before gluing them up, I did notice a slight unfairness along the top edge towards the end. After more sighting, measuring and thinking, I convinced myself it was an optical illusion caused by the blade profile. Therefore, I didn't bother to pack the jig slightly to get rid of it.

Now that the blades are out of the jigs and I can see them clearly from every angle, it's clear that it wasn't an optical illusion. They're still good enough to use, and look fine from most angles, but if I was making another pair I'd pack the jig slightly. This wouldn't be hard to do and would give a better result.

Had a thought about these plywood blades. The weight is pretty good already, but an easy way to improve it would be to replace the middle layer with 2 mm balsa sheet. The middle layer contributes hardly anything to the strength and stiffness of the blade, so replacing it with balsa would be an easy way to reduce weight without any significant increase in labour or cost.

2 mm is the cheapest thickness (thinner and thicker being more expensive for a given area) and would drop about 25% of the weight from each blade, giving a finished result somewhere around 280 grams each. The cost of the balsa would be minimal, under $5 per blade, and although it would require end grain sealing this wouldn't be hard to arrange.

This would be great. A 25% reduction in blade weight would have a substantial effect on the "swing weight" (or polar moment of inertia if you want to be techy) of the oar, which is going to be a great benefit to the biomechanics of grunting your rrss off for a couple of miles. Obviously it would also help the static balance of the oar too. I think I'll have to experiment with this.

Anyway, I reshaped the cedar shaft blanks yesterday and also cut the hoop pine facing for the back faces. I'll laminate those on today.

Got the first bits laminated on the oar shafts.

I have an aluminium (yes you Murricans, that's how you spell aluminium) straight edge that is 2.4 metres long, 80mm x 40mm, with 3mm thick walls. It's very handy when I want something that is dead straight and will stay that way, which is why I bought it years ago of course.

I used that to keep the shafts straight while doing the first laminations, with packing tape up and down it to stop the pox sticking to the metal. I did stick something to the metal though, that being stops each end of where the wood was going. These were just to reduce the degrees of freedom once everything was slippery with glue. The stops are only stuck on with Prep Multihesive, which is quite weak (compared to pox) and easy to get rid of later. It also sets up fast, which is handy for jobs like this. I also used some of my plywood planking clamps as packing under the screw clamp ends, just to protect the cedar oar blanks. The whole thing went well.

Naturally though, I did have a better idea after doing all of this. I should have done this laminating before doing any shaping of the oar shafts. The reason I didn't is because, at the time, I wasn't sure if I'd want the hoop pine laiminated on before fitting the blades or after. Now I know. I want it before. Hey ho.

Had another better idea too, following on from the balsa-core blade idea. If I'm going to make lightweight oars suitable for racing there's no point screwing around. Hollow shafts are obviously the way to go. Usually these would be D-shaped in section, but although this is necessary at the rowlocks (to allow feathering) it makes no sense anywhere else. The most logical section is a basic box, providing the oar will only be loaded within the elastic limit of the timber (and if it isn't, you've screwed up anyway). A basic box is also the easiest hollow section to build, which is another bonus.

Obviously it'd have a small radius on the corners of the box section, and be packed to a D shape at the rowlocks to allow feathering. If it's done properly there's no reason why it should look clunky, and it would be the most functional solution. So, I'm thinking that's the way to go for the next pair of oars I make.

Anyway, pics of the glue up are attached.

The other bit of progress is that I got the first undercoat on the inside of the boat. This is just for the areas which will be non-skid paint. They're going to be done in the cream colour the paint was before I messed with tints (I saved some of the original).

It made sense (to me anyway) to drop these in first. Masking a fair line off the chine logs and frames was easy, and it now gives me a fair line to mask the other way for the green undercoat that will be used on the garboard, chine logs, and the narrow edging strips on the bottom. The plan is to get the green done, then mask the cream patches up again and drop the non-skid topcoats in last.

Often people like to make their non-skid patches have rounded ends and corners. I decided against that as I reckon it'll look sharper without any "blobby" bits. So, it'll just be corners between frames and a point at each end. I like it.

Haven't made any more progress on the oars, but have modified the rowlocks to suit my preference. As mentioned, I'm using Gaco rowlocks. I like these since they are good for pitch control, as well as being light, cheap, quiet and very strong. They don't look as nice as bronze but are far lighter, and will work better than most fancy rowlocks on the market at a fraction of the price.

However, personally I prefer an open-topped rowlock so that I can withdraw the oars from the rowlocks easily. I don't like having the rowlocks permanently attached to the oar. I'd rather attach them to the boat. So, what I've done is to cut away the upper section of the rowlock to convert it to an open top. This is fine since they are massively strong anyway. Even with the tops cut away, they are still strong enough to handle an emergency stop from full speed (ie: reverse blades, drop blades into the water, and hold them fixed relative to the boat). The resulting shape will still hold the oar securely at the normal rowing position, where the shaft is thickest, but the taper of the shaft will allow the oar to be removed from the rowlock once it is slid inboard.

There's still a little bit of cleaning up to do, but the procedure was basically simple. On the inner rear face are five grooves, which allow the rowlock to flex when the top is being clipped or unclipped to allow extraction of the oar. In practice, almost all the flex occurs in the top section past the fifth groove, with the rest of the rear section being very stiff. Since the rowlocks are made of polypropylene they can be worked with ordinary woodworking tools.

I started with the rowlock clipped together as standard, placed it on edge on top of a chunk of wood, then cut through the fifth groove with a tenon saw. I then stood the rowlock up vertically and made another cut to free the section I didn't want, while leaving the retaining clip section on top of the pivot pin. These cuts were then cleaned up a bit with a sharp chisel, working vertically down onto a chunk of wood with the rowlock on edge again.

The upper ends had a bit of a ridge in the centre, so I smoothed that a bit (chisel again, use freehand) to prevent damage to the oar shafts when extracting them. I'll do a bit more judicious shaping with a file or two, but the result so far is as seen in the pix. I think this will work very well.