Penobscot 13 Build

[Kunzwerks]

Attachment 103154

Thanks Daniel … your apple is looking great. Umm … that doesn’t sound right.

[Kunzwerks]

I'm thinking about using Ramboard to make plank patterns. It comes in a roll at building centers, and is a very stiff cardboard. I'm also going to use it to cover my 'boat shop' floor, since my shop is a finished great room in our barn. Management will NOT be happy if I gunk up the floor with epoxy.

https://www.homedepot.com/p/Ram-Boar...8200/202088850

i look forward to seeing your build. Please share.

[dt123]

I see the stiffness as being a drawback. I think having a thinner material be able to drape and conform to the curve, and be easy to cut quickly in place, would be better. But give it a try and report back!

[dbp1]

I see the stiffness as being a drawback. I think having a thinner material be able to drape and conform to the curve, and be easy to cut quickly in place, would be better. But give it a try and report back!

It can't be _that_ stiff -- it comes on a roll!

And I would think that you want a material that is close to the material you'll be using -- as if it is too floppy, the shape that it conforms to (and that you cut it to) wont be how the actual wood lays on the boat.

Having said that, I used cardboard all the time! Throughout most of the building process, I was collecting big boxes under the hull to use to cut out templates for various parts -- at least for _flat_ parts, cardboard (at least, the tougher stuff used in boxes) works perfectly. I know people often use lightweight plywood but it's still somewhat expensive and, at least for what I needed it for, never seemed quite worth it. The only time it didn't work was when I used a piece that was a little too floppy, and the resulting template wasn't quite the right shape (I didn't notice this until I cut out the wood! But it was close enough, and on a skeg that the designer said could be smaller, or done away with entirely).

[MushCreek]

I've used Ramboard before, for it's intended purpose of protecting floors during construction. My biggest concern will be finding a way to cut it cleanly, quickly, and accurately. I find paper patterns to be tedious to trace around. With care, the cardboard plank patterns might even be re-usable if someone else were to build the same hull. Time will tell.

[RowAndSail]

Regarding waste of ply, I can confirm that when I built mine, I went with the overly-wide-rectangular-strip method. In the end I did not have enough and needed to get an extra sheet. At the time, they cost me $80 each, so not as bad as what it is now for you. That price per sheet is a shocker to say the least.

[Kunzwerks]

Cutting the shape of the deadwood and securing it in place took more time than anticipated. First was planing a flat on the hull centreline, and ensure it was plumb. Since you have to lean over the hull while planing, it’s difficult to keep your plane level. Here you see I used an upright stick placed in the vertical middle of the transom as a reference. Using a cabinet square, I was able to sight that the gap between the square and the stick was not skewed and my hull flat was level.

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The deadwood is western red cedar, which is too soft to use as a deadwood. But, it’s what I had on hand. To guard against the inevitable scapes and dinges, I added a 3/8” thick strip of Osage Orange. Again, I had it and saved me from ordering half oval strips of brass. Osage Orange is an extremely durable wood and is considered to be one of the most decay resistant woods in North America. Then everything got glued down.

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The outer stem was chamfered and after doing that, I realized the error I made. Wasn’t thinking, obiviously. The chamfer should end at the bottom of the top stake … not the top. I went too far on my chamfer. I decided to leave it, instead of making another outer stem. This will make it not so easy to fit the rub rails and sheer strake moldings. I’ll think of something ….. suggestions?

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[dt123]

I see what you did there. I think you just have to adjust the angle of the faying surfaces of the rub rails to match. They were going to be angled anyway, and now a little less angled. No biggie structurally. Just not exactly right cosmetically. Only you can decide if it bothers you enough for a redo.

Believe me, no one but you will know how it was supposed to look. I have a few "features" like that on my boat. As they say in computer programming, when you have a bug in a program that you just can't seem to fix, "Give it a name, and call it a feature." This is your Extra Chamfer feature.

Way cool to have Osage Orange wood on there. Down where I live we call that Bois D'Arc wood. It is so rot resistant you can bury it in the ground, like for a fence post, and it will last nearly forever.

[Kunzwerks]

I see what you did there.

Yup, … let out a few curses when I realized what I had done. But, as you say, it will become a feature. Should be OK.

[Kunzwerks]

The last piece clamped in place before the flip.

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….. and the flip.

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Well that felt good. Before all the molds come out of the hull, the breasthook and rub rails need to be installed. Starting with the breasthook, I am using yellow cedar in a precarious looking glue up. Hoping for a tight seam if it all holds till the glue drys.

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[Rich Jones]

Nicely done!

[Kunzwerks]

The breasthook is made from 2 pieces, joined at the centre. It helps to choose nice looking wood grain for your pieces. The joint is a cut on an angle, determined by the bevel gauge placed against the sheer clamp. Both pieces get cut at that angle.

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The angled surfaces are then glued together as in the photo of the previous post. It’s a little tricky to clamp together, but it helps if a spline is part of the joint. The assembled breasthook is placed back on the bow, ensuring it’s centred. I used a string to help visualize where the centreline was. Each side of the breasthook is now square to the sheer clamp. Mark off the breasthook by running a pencil line underneath the breasthook along both sheer clamps.

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Cut off the port and starboard sides and the breasthook will magically fit into place.

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Then with a little trimming and smoothing … actually, a lot of that.

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[timo4352]

Very nicely done

[Steamboat]

Well done!

[KenStocker]

I like your process, and the outcome is lovely. Even the grain on the inside of the curve looks great. Well done!

Ken

[dalekidd]

Looks fabulous! I'll be doing my breasthook shortly. Going to mark this page and come back to it.

[steffenme1]

This looks awesome, I really like the Penobscot and I'm hoping I can tackle one in the next few years. Excited to see your progress.

[Kunzwerks]

Thank you for all your comments, gentlemen.

I did a dry test fit on the rub rails and found it very difficult to hold the sheer line, especially at the bow of the boat. So I decided to section it and further cut curved rub rails to follow the sheer line at the bow. The mid and aft sections remain straight. A little more work, but securing it on the boat was so much easier.

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[dt123]

Hey, Kunz. I guess I still don't understand why you are not using screws to attach things like the rub rails and are instead using all those clamps and making the rub rails in parts, some curved. When I did mine, I ripped continuous, straight 14.5-foot rub rails out of Douglas Fir, and curved and twisted them right to the sheer line with screws spaced one foot (@) apart. A quick pass with a bottom bearing flush trim bit on my handheld router made a perfect top surface.

Could you explain your strategery? What is it you are trying to avoid doing it your way? Are you using an unbendy type of wood or thicker dimensions than specified? Not being critical at all, just want to know. dt123

[Kunzwerks]

Hey dt123, I’m using yellow cedar for the rub rails 3/4” by 5/4” with a 20 degree bevel on the underside, which is per plan. Trying to bend the rub rail in place was not working and could not hold the sheer line at the bow end with clamps in place. Maybe the grain of the wood or the internal stress of the wood working against the bend … don’t know. The plans call for gluing the rub rails in place with screws or clamping it. Maybe I needed more clamps, but the way I looked at it, was to see what else I could do to solve my problem.

When something is not working, trying harder with the same method usually (in my experience) gets poor results. Thinking of another way to accomplish the task works for me … maybe not the quickest, but certainly less stressful. A bigger hammer doesn’t always work. I’m not trying to make more work for myself, although some of my process looks that way … I would say it makes aspects of the work easier and more enjoyable. Case in point; the clamps I made for the planking took maybe an hour to make, yet saved me hours if not days of sanding screw holes filled with epoxy. Also, spilling the planks was easier for me than what the instructions laid out, and also saved expensive plywood. Just saying …

[dt123]

Must have been the yellow cedar that was causing the problem. I have just read up on that type of wood, which we do not see down where I am. Very cool to be able to use it. I think you are overestimating the time it takes to level an epoxied screw hole.

[Kunzwerks]

There are several things being prepped; the daggerboard box, twarts and mast partner. Nothing worthy of photos at the moment.

The position of the mast partner was of some concern, due to the rake on the mast that has to be accounted for, which is specified at 3/4” per vertical foot. That meant the hull has to be level, to get an accurate tilt on the mast. There is no mention of levelling the hull in the instructions, and I contacted Arch Davis to get some advice.

In my shop the floor is not level. Not a problem propping things up to achieve level, however I didn’t have confidence that I could reference off the cradle for the hull, to determine if the hull was level. One end of the cradle could be higher and even a small difference, makes a big change when measured several feet out. Again, the instructions don’t mention constructions details for the cradle to ensure the hull sits level.

Levelling side to side… no problem.

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For the bow to stern level, Arch recommended I use the transom as a reference since we know that it is 20 degrees from vertical. Positioning my adjustable protractor on the transom to get a true vertical, that is parallel to a plumb bob, gets me a level hull … or pretty close. Turns out, I had to drop the stern end about 2”.

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How do other builders get their boat level? Determine the waterline or use some other reference?

[timo4352]

Your way of leveling the boat fore / aft is very clever...
On my last build I had a waterline and a few level lines on the frames to pick from.
Your boat is looking great.

[dt123]

On the Penobscot 14, the bottom of the deadwood, and top center portion of the keel, are supposed to be level fore and aft. This is set by the frames in the beginning when you attach the keel, carries through when you attach the deadwood, and then by the cradle after you turn it over. Assuming your strongback is level in the first place.

My strongback was level from Day 1, so I never had your issue. I made the cradle before I did the flip and leveled the bottom of the cradle as I made it, sitting on the boat. After the flip everything was thus still level.

Having things level at this point is important because your aft seats and thwart are made level, and the pieces won't match up in the end unless they are really level. Also your centerboard might not work right if the case top comes in at the wrong height. I learned the limitations of a bubble level when my centerboard case came in about a half inch too short. In hindsight I wish I'd used a laser.

[Kunzwerks]

Thanks timo4352, but the idea of using the transom for levelling fore and aft, goes to the designer of the Penobscot 13 …. Arch Davis. Now that the hull is level, I’m still scratching my head on getting the rake of the mast done.

[Kunzwerks]

On the Penobscot 14, the bottom of the deadwood, and top center portion of the keel, are supposed to be level fore and aft.

I thought so too, and asked Arch if that was what I was suppose to do. He suggested the transom as the reference.

I guess there’s more difference between the 13 and 14 than one would suspect. Further, all the seats and thwarts for the 13, line up on the top of stringers, so no levelling required. Those stringers were aligned as part of the layout on the molds. I just need the hull level for the mast partner position to account for the rake of the mast.

[dt123]

Huh. That really is kind of weird, not having anything to point to on the boat as being "level." No wonder you had an issue. I assume you know how to use your plumb bob to find the center of the mast partner hole now. I can explain if not.

[Kunzwerks]

I assume you know how to use your plumb bob to find the center of the mast partner hole now. I can explain if not.

It seems I’m going about this the hard way. Must be some aspect I’m missing, so any advice is very welcome. I have the vertical line (plumb bob) over the mast mortise in the stem, but the offset of 3/4” per vertical foot, leaves me in mid-air. Do I have to apply some trigonometry that I have forgotten long ago?

[dt123]

OK, so let's say, for easy numbers, the distance between (1) the top of the stem at the center of the mast and (2) the bottom of the mast partner at the center of mast, is 24 inches. The offset over that distance will be 1.5" (2 feet times 3/4" per foot.) These are just easy numbers for talk purposes. Your measured distance will be different, but convert it to feet and multiply times .75 to get inches offset.

Still using the easy numbers, mark a point on the stem center line 1.5" aft of the stem mast center point (a Sharpie dot on a piece of masking tape will do). Drop your plumb bob over that point and hold it there. The string at the mast partner bottom is the center point of the mast partner bottom. You position your mast partner so the center of its hole coincides with the string, and fix it to the boat.

[Kunzwerks]

The offset over that distance will be 1.5" (2 feet times 3/4" per foot.) These are just easy numbers for talk purposes. Your measured distance will be different, but convert it to feet and multiply times .75 to get inches offset.

Still using the easy numbers, mark a point on the stem center line 1.5" aft of the stem mast center point (a Sharpie dot on a piece of masking tape will do). Drop your plumb bob over that point and hold it there. The string at the mast partner bottom is the center point of the mast partner bottom. You position your mast partner so the center of its hole coincides with the string, and fix it to the boat.

OK, I think I understand. You have confirmed the same calculations I made, so that’s reassuring. I’ll try this tomorrow. Thanks.

BTW, a little trigonometry converts those measurements to 3.576 degree tilt from vertical. Call it 3.6 degree. No … I’m not going to measure 3.6 degrees ! Seems like a lot of tilt though?

[Kunzwerks]

This is for clarification, for 1st time boat builders, like me, to set the mast rake. It’s easy, once you know how.

Having the hull level, both fore and aft; and side to side …. Position a plumb bob directly dead centre over the mast mortise as in the first photo. Place a scrap board where the mast partner would be positioned, almost touching the vertical string. Take a measurement from the stem to the underside of the scrap board, as shown. If the thickness of the scrap board is the same as the mast partner, then take the measurement to the top of the board. If not, add the thickness of the mast partner to the previous measurement.

Apply some math as explained by dt123 in post #64, to get the offset measurement. On my boat the total measurement from the stem to top of mast partner was 16”. The math calculation indicated an offset of 1”.

Without changing the anchor point, raise the plumb bob so it is just above the actual mast partner that can now be positioned in place. Place a mark under the plumb bob and measure the offset number towards the aft end. This will be the centre of the hole to be drilled for the mast.

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I made a convex shaped mast partner. Therefore I had to account for the additional “thickness” by placing it on a flat surface to measure from the said surface to the top of the partner.

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[Kunzwerks]

Work has slowed down on the Penobscot 13, as my time was (is) demanded elsewhere. Such is life.

I have managed to get a few hours work in here and there, and finally got the daggerboard case made and glued in place. I still worry if its water tight … won’t know until the boat gets in the water. The daggerboard is protruding since the boat isn’t sitting high enough for the daggerboard to go all the way down. Also, got the seat beams done and went a little fancy on the butt joints.

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There are choices when it comes to seating placement and design. I decided on this one. Boards are rough and need to be further trimmed before final install. I decided not to place a traditional twart against the daggerboard case. This will leave more leg room in an already small boat.

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[garyb]

Nice craftsmanship on your handle on the daggerboard there.

Yeah, daggerboard and centerboard logs are notorious for having subtle (or even not subtle) leaks. Hopefully you have it sealed good.

Sure looks pretty, in any case.

[Benny]

Beautiful work

[Rich Jones]

It's looking really good!
If you glued that centerboard case down with thickened epoxy, expect no leaks.