Spars and Engines
Over the coming months, most of the work on the Morgan will be focused on the spars and rigging. Two big spars are currently in the main shop. They’re both douglas fir from Washington state. The first is the bowsprit, a massive timber.
Trev has been working on shaping this fellow for a while now, and his progress is more apparent every day. He’s shaped the tenon at the end of the timber and rounded over the top edges.
While the top stays flat with rounded corners, the bottom of the bowsprit will be fully rounded.
Here he’s laying out the guide lines for rounding the underside. Rounding is done in stages, by creating a series of smaller and smaller facets. Here’s what it looks like. The end of the piece is marked with centerlines and the desired circle. In Trev’s case, he’s only doing the upper half of the circle.
Next, 45 degree angles are marked tangent to the circle using a bevel gauge.
The points where those angles intersect the face of the block are carried down the spar as the guide lines you saw above.
There’s also a numerical way to arrive at the 8-sided guide lines. Looking at the drawing again, I’ve marked the width of the 8-sided face as X and the width of the 45 degree tangent faces as Y.
The total width of the face of the part is X + 2Y. The ratio of X:Y is 1.41 : 1, and you can use this ratio to come up with the values for X & Y if you know the width of your piece. So, if Trev’s bowsprit is 20″ wide, you get X + 2Y = 20. Since X = (1.41)Y, we can substitute this into the equation: 1.41Y + 2Y = 20. We can add the 2 Y terms and get 3.41Y = 20. Solving for Y, you get Y = 20/3.41 = 5.86 Since X + 2Y = 20, X = 20 – 11.73 = 8.27.
Whew. And that’s for 8 siding.
After the corners are cut off,
the spar is re-marked for 16-siding. This can be done using a bevel gauge set to 67 !/2 degrees, set on the flat faces with the blade just tangent to the marked circle.
As before, the intersecting lines are marked along the piece, and the high points are taken off.
In real life, it looks like this:
It’s looking very close to round by now. If you take the points off evenly, you’ll end up with a 32-sided spar. This is very very close to round.
Trev uses a power planer to make long, consistent cuts as he takes off the corners.
After that, all the final rounding is done by sanding.
As they say, it’s easy once you know how. You may have noticed that in the photo of Trev marking the guide lines that he’s having them taper to a point. There’s no formula for doing that taper, he uses his eye and experience.
The other big spar in the shop is the lower foremast. This spar was turned at the Spar Shop at Gray’s Harbor Historical Seaport in Aberdeen WA.
The old foremast was not in very good shape, and it had been treated with pentachorophenol, an excellent wood preservative that is naturally pretty toxic to everything and everyone.
It wasn’t worth putting it back into a boat right through the fo’c’sel where the crew would be sleeping.
The old spar was measured, and all the hardware locations recorded.
The hardware was then cleaned up and put onto the new spar to make sure that everything fit properly.
This is the spider band.
The spider band will attach to the foremast about waist height above the deck. The tubes hold the belaying pins (the wooden rods that are used for securing lines that go up to the sails)
This is the futtock band.
And how it will look in place:
This piece is a bit trickier to explain, and perhaps I’ll just let Wikipedia tackle it.
This spar was turned along its entire length when we received it, and top 11′ or so needed to be made into a tapered square. Here’s what we’re talking about (from the Morgan model)
The tapered section is called the Doubling, because this is where the lower foremast overlaps the fore topmast. There is a platform, called the Top which slides down over this tapered section and lands on the shoulder created by the round section below the taper. The top has a square opening in it that receives the lower section of the top mast.
At the top of the tapered section is a large wooden piece called the Cap. This fits onto a tenon at the top of the taper and has a round hole in it that the top mast goes through. This is the mizzen cap, but they all look pretty much the same.
The Cap and Top hold the topmast in two places, just like the mast partner and mast step hold the lower section of a mast as is goes through the deck to the keel.
In the previous post, you saw the topmost end of the lower foremast laid out for the taper.
This taper was laid out using long battens to create cut lines, and then the rough flats were formed using a chainsaw, axe, and adze.
These were cleaned up with hand and power planes.
The level is used to make sure that there is no twist along the length of the flat surface. If there was twist, the level would show that area as slightly sloped to one side.
The spar rakes aft just a little bit, and thus, the shoulder where the top sits needs to be beveled to keep the top level. It was easy to measure the existing bevel, but a little tricky to transfer the shape of the flat, angled shelf onto the round surface of the spar. Luckily, we have a laser guide that’s perfect for the job. The laser projects a flat plane of light that, when properly positioned, marks the exact location of the bevel across the curve of the spar.
I know, it’s definitely NOT how they would have done this in 1841. They would have used a steam-powered laser of course…
Once marked, the bevel can be cut with a handsaw, and tuned up with chisels and hand planes.
After that, the cap is slid onto the spar and the fit checked.
Comealongs and a rolling floor jack are used to slide the heavy top along the mast as it’s checked and adjusted.
Ali has been busy painting up on the foredeck recently. Everything is looking very nice and finished there.
She’s also been stripping old paint and prepping the upper deck.
That’s a huge job.
John has been working on the breasthook that ties the sides of the boat together just above the bowsprit. It will go across the opening to the right of Mariah.
There’s a lot of shape to this piece.
Dean forked it up to the boat the other day
It just made it… we’d be toast without the boom extension.
John built a platform for the breasthook to slide on for final fitting to the hull.
He’ll be able to slide the piece to the boat, check the fit, slide it out of the way, tune it up, slide it back… repeat, repeat.
Jamie, Matt, and Nick have been working down in the hold getting the foremast step properly located and attached.
The base of the foremast notches across the keelson,
and the step captures it to prevent fore-aft movement.
The main mast step has also been installed.
This is an interesting piece. If you’re familiar with mast steps, you’ll recognize the mortise cut into the step to receive the tenon from the base of the mast. But unlike most mast steps, this one has a large athwartships span. It is more common for mast steps to be oriented in the fore-aft direction, like this much smaller NY 30′s step.
The idea of having the mast step run along the length of the boat is usually to spread the load of the mast across multiple frames. We believe that the main mast steps in whaling ships are oriented side-to-side because of the mast stresses particular to these types of vessels. In a whaling ship the main mast has significant side loading. Whale blubber is pulled off of the whale and hauled up over the starboard side of the ship using a block and tackle attached to the main mast. This would exert a great deal of side stress on the mast. These ships were also hove down (literally pulled over sideways) by their main masts to expose their undersides for repair at port.
The ballast has been moved around a bit down below. We’ve shifted a sizable portion of the led forward and along the keel to balance the boat.
This is a work in progress, and we’ll be adjusting this more over time. In the meantime, we’ve got a lot more lead for the final ballasting next year.
Lastly, I’ll leave you with a few images from the antique marine engine show that Scott organizes here each year. First, a small thing. This is a working scale model of the steam engine in the Sabino (one of the seaport’s boats that operate on the Mystic river). Here’s a video of the original:
And here’s the model, built by Greg Young.
And this amazing thing is an actual wrench that Greg made specifically to work with the custom nuts that he made for this model.
And on the other end of the scale, seaport staff and volunteers have been working for over a year on an Atlas Imperial engine that was donated to the seaport last spring. They finally got it up and running just before the show. You could feel the earth move when this beast got going. Scott is the fellow in charge of the vise-grip throttle.