The San Marco mosaic ship c. 1150 by Louie da fly - 1:75

[Mark Pearse]

On 8/16/2023 at 3:07 PM, Louie da fly said:

But even though this looks somewhat weird

There looks to be an optical illusion, I think it's the tapering of the hull against the squareness, & the rectangle appears wider towards the stern. If there is no evidence the structures were not tapered, would it be wrong to try a version that has a very slight taper towards the stern?

[Roger Pellett]

Steven,

 

Your aftercastle’s second iteration looks logical to me.  I believe that these old vessels can be considered as two separate parts; the hull, and the structures built on top.  It was not until the 1500’s that the castles were integrated into the hull form.  Projecting the bottom of the aftercastle would involve cutting into and weakening the hull.

 

Roger

[woodrat]

This vessel is of an era preceding the use of the large athwartship transom timber at the stern to support the sterncastle. In its absence, it will be necessary to insert curved support timbers which are seen in many of your illustrations.

 

 

Dick

Edited August 18, 2023 by woodrat

[Louie da fly]

7 hours ago, Mark Pearse said:

There looks to be an optical illusion,

Oh, certainly. But I'm convinced that the artists were portraying what was there, and who am I to decide my concept of "rightness" trumps what was actually done at the time?

 

5 hours ago, Roger Pellett said:

 I believe that these old vessels can be considered as two separate parts; the hull, and the structures built on top.  It was not until the 1500’s that the castles were integrated into the hull form.  Projecting the bottom of the aftercastle would involve cutting into and weakening the hull.

Yes, I agree, on both the issues you raise.

 

1 hour ago, woodrat said:

it will be necessary to insert curved support timbers which are seen in many of your illustrations.

Yes, I'd already decided to do that. With a scroll saw it shouldn't be all that difficult to do identical ones, but in this case each pair of knees (starboard and port) will be of a different length from all the others as the hull tapers but the aftercastle remains the same width. I'm even looking at the possibility of radiating the knees out perpendicular to the curved line of the hull. (PS: I've sent you a PM regarding a facet of the rigging).

 

Steven

Edited August 18, 2023 by Louie da fly

[Louie da fly]

Mock-up in balsa for the side rudders, based on one in the mosaic pictures.

And the roughed out rudders. I discovered too late that one of them was too thin at the handle end, so I glued another layer of wood to thicken it up. I'll post a pic of the completed ones when they're finished.

The deck for the aftercastle under construction:

 

And my first experiment in curving timber really tightly - to form the top. Worked fairly well, but the wood started to char - I can't lower the temperature of the soldering iron. But I have hopes of a vegetable steamer that I have permission to use outside the kitchen.

 

Steven

 

[Roger Pellett]

If you get vetoed on the vegetable steamer, you can hook your soldering iron into an inexpensive light dimmer switch to control temperature.  You can also  your wet your wood strips and nuc them in a microwave.  The last, probably as popular as using the vegetable steamer!

 

Roger

[Louie da fly]

I've temporarily (with a couple of small dabs of glue) fixed the aftercastle deck to the hull to adjust the position and verticality (is that a word?) of the mizzen mast, with quite pleasing results. There's still a little wriggle room in the mast partners which will allow me to get it exactly right.

    

Additionally, I've removed the deck framing below the aftercastle, which was in line with the main deck. I intend to make everything below the aftercastle into cabin space, with a lower deck level. I'm not sure at the moment how much work I'll put into this cabin space, as it will be hidden anyway, but I'm thinking of having a crew member climbing up through the companionway onto the after deck to add a bit of interest. The masts haven't yet been cut to length - I'm still thinking about exactly how I'm going to configure the tops and calcets

And after referring back to the paper by Lawrence V. Mott of Texas A&M University entitled The Development of the Rudder A.D. 100-1600: A Technological Tale, I've realised that I'd misinterpreted the rudder shape somewhat, as it was intruded on by other items in the picture I was working from (refer to the mosaic picture in my previous post), and that I'd missed the fact that both rudders were shown in the mosaic (though the artist seems to have got the nearer rudder facing backwards).

And, following Mott, here is the aerofoil (or perhaps aquafoil?) cross-section of the rudders.

 

That's all for now.

 

Steven

 

[Ferrus Manus]

nice "starboards"! 

 

[Louie da fly]

Here's my first attempt to do a calcet based upon the mosaic ships. There was quite a bit of guesswork involved - even guessing that the black things above the tops actually were calcets rather than something else - I'd originally thought they were either the mastheads or flagpoles, but their strange shape, pretty much consistent in 4 out of 5 of the mosaics got me thinking they must be something else, and the only thing that seemed to fit was a calcet.

  

  

Why a calcet would be that particular shape, I have no idea. But I can understand that there could be a wide variety of shapes that would still do the job. So rather than get too involved with the mystery of the shape (that can be for later) I just made one that seemed to be the right shape and would do the job. Based on pictures of calcets - both drawings from some centuries later than this model, and the photo of the Ma'agan Mikhael calcet referenced above, I've given it two sheaves. I worked out a possible configuration to make that work, but again, this is pure speculation.

There are two tyes attached to the lateen yard, each of which runs through one of the sheaves in the calcet (at the top of the mast) and down. They come together to form a strop around a block which connects via the halyard to a knight at deck level. There's no direct evidence that this is how it was done, either iconographic or written, but it should work.

 

So here is the calcet for the mizzen, with a scarph joint to connect it to the mast itself.

 

Note: The scarph joint doesn't line up perfectly - this is a prototype; I've cut it right up at the top of the mast, above where it's supposed to be, just to see if it works. As it seems to be ok I'll now do the real joint in the correct position - the bottom of the joint should be in line with the base of the "crow's nest". I think I can arrange things to the tyes don't foul the sides of the crows nest, which is an open framework (see pictures in post #155 above).

 

 I've also added more deck beams for the main hull and finished the deck beams for the aftercastle, with openings for the mast partners and for a companionway coming up from the cabin space below.

And then I removed the aftercastle to work on the deck beams and sides.

I added a railing around the aftercastle, which is how I interpret the mosaics.

 

Next I plan to do all the rest of the deck beams (allowing openings for two hatches - one between the aftercastle and the central mast, and one between that mast and the foremast). And make and install beam clamps for the deck of the cabin below the aftercastle. Unfortunately my cheap soldering iron which I've been using as a plank bender, up and died today, So it looks like I'll have to get another one - unless I can make the vegetable steamer do the job. Worth a try.

 

Steven

 

 

 

 

 

[Ferrus Manus]

Hey Steven, i'm building what will likely turn into a nef. Just letting you know, because i know you're really into ships from the High Middle Ages. I will likely also need your help. 

[Louie da fly]

Yes, happy to help. I take it you haven't started a build log yet.

 

Steven 

 

[Ferrus Manus]

look for it in the pre-1500 kit logs! I look forward to your presence, as i always do. Cheers! 

[Ferrus Manus]

Can someone explain to me how a steering oar actually steers a vessel, and how it is operated?? 

[Glen McGuire]

6 minutes ago, Ferrus Manus said:

Can someone explain to me how a steering oar actually steers a vessel, and how it is operated?? 

I can't speak to the mosaic ships that Steven is modeling, but when I was doing research for my Oseberg build, I came across this webpage describing the steering oar for Viking ships.  Perhaps the concept is the same or similar.

 

https://www.vikingeskibsmuseet.dk/en/professions/boatyard/building-projects/gislingeboat-2016/the-hull/rudder-and-tackle

[Ferrus Manus]

It seems like a rudder would take at least two men to operate: one on the tiller, and one to continually loosen or tighten the bottom (or top?) attachment to allow the rudder to move horizontally. 

[Louie da fly]

In a few words, it's swivelled from side to side as you do with a stern rudder. Works just the same as a stern rudder, right down to having a tiller. But Mediterranean ships usually had one on each side, often with a single steersman holding both tillers at once. Side rudders also swivel in the vertical plane, but that's just to get them out of the way (i.e. out of the water) when the ship enters port/is in shallow water etc. Or so you can use just a single one.

 

For more information on the whole side rudder thing, I'd recommend you read The Development of the Rudder A.D. 100-1600: A Technological Tale by  Lawrence V. Mott of Texas A&M University. It used to be freely available on-line along with a huge number of other master's theses in the University's website, but when I checked recently it went to a general site that just told you about the University itself. A terrible shame; it was a really good resource. Apparently it's now published as a book which you can buy, or access through inter-library loan.

 

BTW, Mott makes the point that side rudders are actually more efficient in steering a ship (of this size and type, presumably) than a stern rudder, as they're freer of the turbulence caused by the hull. BTW, traditional whaling boats still use a steering oar - they race them here in Victoria, Australia. I've seen them in action.

 

Steven

Edited August 31, 2023 by Louie da fly

[Ferrus Manus]

So the bottom attachment (rope, withy, whatever) would be regularly kept loose enough to allow for sideways motion? 

[Mark Pearse]

Hi Steven

 

Have you come across the photos of Alan Villiers? In the 1930s he spent some time on lateen rigged dhows. No doubt many differences, however it's just possible some the the technical questions might be helped by some details that are visible. His photos, if you haven't seen them, are very good quality images.

 

[Ferrus Manus]

I saw those on someone else's build. I didn't know ancient shipbuilding techniques existed as late as the middle of the 20th century. 

[GrandpaPhil]

Many things are slow to change, especially if it works well.

[Cathead]

On 8/30/2023 at 8:18 PM, Louie da fly said:

But Mediterranean ships usually had one on each side, often with a single steersman holding both tillers at once. Side rudders also swivel in the vertical plane, but that's just to get them out of the way (i.e. out of the water) when the ship enters port/is in shallow water etc. Or so you can use just a single one...

BTW, Mott makes the point that side rudders are actually more efficient in steering a ship (of this size and type, presumably) than a stern rudder, as they're freer of the turbulence caused by the hull.

Forgive me for a slight diversion, but this discussion of side rudders and the note about one on each side really fascinated me, as I recently purchased a kit that converts a regular canoe into a sailing vessel. As it's difficult to mount and operate a centered rudder on a canoe, this setup uses dual steering oars mounted on a cross-beam. The idea in this case is to use one at a time (whichever is on the lee side) and let the other trail in the water. These also swivel horizontally and vertically so you can store the unused one up on the stern. The system works amazingly well, but I had no idea the dual-steering-oar setup had such a pedigree, I figured it was a modern hack to make the canoe-sailing thing work! To illustrate the point, here's the setup in my backyard and in action on a local lake. Having learned to sail on normal sailboats while growing up along a US Great Lake, the whole side-oar thing was new to me in practice (though I was familiar with its use in Viking vessels);  it does indeed work very well.

 

I don't want to derail this thread into a long discussion of canoe sailing, I was just fascinated by the convergence of ancient and modern.

[Louie da fly]

On 8/31/2023 at 2:04 PM, Mark Pearse said:

Have you come across the photos of Alan Villiers?

Yes, I found quite a number of them on-line, but I never knew the source. Thanks for enlightening me - and yes, they have often proved very useful.

 

On 9/1/2023 at 12:00 PM, Cathead said:

I don't want to derail this thread into a long discussion of canoe sailing, I was just fascinated by the convergence of ancient and modern.

That's fascinating. I never knew about this, and it's really amazing how old proven technology sometimes re-surfaces in the strangest connections. Thanks for letting me know.

 

And now for an update on progress.

 

I think I mentioned that I'd planned to make a cabin below the aftercastle, for the captain/owners. 

 

First I needed to install clamps to support the ends of the cabin's deck beams. It was fairly complicated trying to get the curve and orientation just right, but I think I succeeded pretty well. Here's the stern with the aftercastle removed, and some of the deck beams in place.

And an overall view from above.

Finished all the masts and dry fitted them. The mast steps and mast partners line up quite well, with a little wriggle room to get the masts exactly vertical when looking from the bow/stern. They are all somewhat raked - the foremast (which is in fact the MAIN mast) has quite a pronounced rake forward, the other two slightly back. Lining up the mast partners in the two decks (aftercastle and cabin) to achieve this is an ongoing project, but I think it's going to be ok.

 

Note that they all now have their calcets in place. I tried to get a good contrast in colour between mast and calcet, but I may have to do a bit more to emphasise it.

And planking on the aftercastle deck. You can see the hole for the mizzen and the opening for the stairs down to the cabin. And on the main deck the mast partners and the beams that form the sides of the two hatches, waiting for more deck beams either side of them, to complete the deck structure.

  

I'm planning to have a wall at the forward end of the cabin, with a door leading into the hold via a ladder, so the captain and owners can access the cargo without having to go up a ladder to the poop, down another to the main deck and down a third to get into the hold. I expect I'll have doors to close off the hatches and the companion, as in Woodrat's Venetian round ship.

Here's the first "crowsnest" attached to the mizzen mast just below the calcet. It doesn't have a floor yet; I'm still working out how to keep the halyards/tyes from fouling this structure - I won't have a definite answer until I install the knights on the deck and run the halyards/tyes to them.

 

Steven

 

 

 

Edited September 2, 2023 by Louie da fly

[Ian_Grant]

This is a wonderful example of scratch building.  Really enjoying following along.

 

Probably the calcets' contrast will be enhanced when you wipe on some finish....

Edited September 2, 2023 by Ian_Grant

[druxey]

I'm thoroughly enjoying this discussion/thread! Nice progress on the model, Steven.

[Louie da fly]

The deck beams are complete now, and the planking is finished on the aftercastle (poop) deck. The mizzen mast lines up nicely, too. The aftercastle is still dry fitted, until I have finalised some of the things that need to be done before it's glued in place.

I solved the problem with burning the wooden 'rings' that are to make up the tops. I realised that if I turned off the soldering iron once it got too hot, I'd be able to make the rings without burning. And turn back on, then off etc to keep the temperature below burning. Turned out pretty well. I cut the rings to size, allowing a bit of overlap for gluing and glued and clamped.

 

    

Here are the tops under way. Three tops, each with three rings per top - each one has two in place at this stage.

Unfortunately, when it came to finalising the tops I discovered that having sized them 'by eye', I'd made the circles too big and I had to go back to the drawing board. So I made a bunch of new ones and disassembled the tops I'd made and cut down the rings I already had. This time I got the idea to keep them all to the same diameter by wrapping them around a paintbrush handle that was just the right size.

 

There's still some adjustment to be done - in particular getting the frames straight and square. Again, I can use the paintbrush as a "jig" to get the rings parallel and in the right place, and to get all the uprights square. I find that isopropyl alcohol is my friend - it enables me to soften the glue of a single joint so I can slide the piece one way or another till it's all exactly right. Still in progress, but looking good.

 

Planking for the "captain's/owner's cabin" below the poop. There's a bit of sheer in these planks, as I'd inadvertently put some sheer in the clamps, which then got transferred to the deck beams. Still, a nice problem to be solved, and it's turned out well. The large bit of wood crossing the planking is an impromptu wedge, as there's no room for a clamp, to hold the plank down on the deck beams so the glue would hold it in place properly.

  

I trimmed the edges of the hatch in the poop deck. There's going to be a ladder/staircase down from here to the cabin. 

 

 

The poop and cabin decks have now been sanded smooth. I had intended to have a wall at the forrard end of the cabin, with a door leading to stairs down to the hold. But when it all came together I realised that there wouldn't be enough headroom for the door or the stairs - the beams of the main deck were in the way.

  

I'll still have the wall at the front, but the access to the hold will be through an opening in the deck of the cabin (in a place that reduces the available deck space as little as possible). 

  

Next step - STEPS!

 

Steven

 

 

 

 

 

 

 

Edited September 8, 2023 by Louie da fly

[Ian_Grant]

Steven, you work so quickly, puts my scratch effort to shame. And your true-to-the-ship framing is wonderful!

 

There are soldering irons which allow you to set the tip temperature, but they're more expensive.

[Glen McGuire]

6 hours ago, Louie da fly said:

I find that isopropyl alcohol is my friend - it enables me to soften the glue of a single joint so I can slide the piece one way or another till it's all exactly right.

Hey Steven, can you explain what you are doing with the alcohol in more detail?  Are you applying it to a joint that has already been glued?  And what kind of glue does it work on?

[Louie da fly]

12 hours ago, Ian_Grant said:

Steven, you work so quickly, puts my scratch effort to shame.

Not at all. Look at the time-frame on my dromon and restoring the Great Harry. I can be very slow indeed, but sometimes things move faster, for which I'm very grateful. On the other hand, I'm gobsmacked by your RC quadrireme. I'd love to do something like that, but RC and moving parts are a complete mystery to me.

 

Regarding soldering irons, yes, I'm sure you're right, but I don't want to spend a lot of money if I can do it on a shoestring, and now I've found a workable method I'm prepared to live with the extra "fiddle" to achieve the result cheaply. I don't actually use the soldering iron for soldering anyway.

 

Glen, yes I apply it to joints where the glue has already set and I want to alter it - either completely undo the joint or just give it a tweak. The isopropanol makes the glue go gooey so you can adjust the joint a bit (or take it apart completely), and it dries solid again (usually, though I often back it up with a bit more glue, just in case). It usually takes a couple of applications to get it to work properly, but I find a drop or two at a time is enough.

 

By the way, thanks to everybody for all the likes and comments. It's encouraging to get them.

 

Steven

 

 

Edited September 9, 2023 by Louie da fly

[Mark Pearse]

On 9/9/2023 at 9:07 AM, Louie da fly said:

The isopropanol makes the glue go gooey so you can adjust the joint a bit

Hi Steven

 

What glue does this work on?

 

Mark

[Louie da fly]

PVA (otherwise known as "white glue") - I use Aquadhere. BTW, isopropyl alcohol or isopropanol is also known as rubbing alcohol and can be bought at Coles of Woolies under the name of Isocol in 75 ml green plastic bottles - and 75 ml lasts for months.

 

Steven

Edited September 11, 2023 by Louie da fly