Trireme Olympias by Richard Braithwaite

[Richard Braithwaite]

Ive chosen the same wood to build the spars (Lime) as used for the rest of the hull. Spruce might have been nice but I always think the grain looks abit to big at this scale.

Her is the Main mast tapered and marked out for "octagonalizing":

The base of the mast is square where it fits into the tabernakle and the top is tapered to fit the mast head fitting described earlier.

The square base is finished with a radius at the forward edge to make raising and lowering the mast easier: 

Finally, both masts with their masthead fittings:

 

[Richard Braithwaite]

A short digression on the rig of Olympias...

 

There were a number of collaborators in the design and construction of Olympias andO.T.P Roberts was resonsible for the design of the rig (I have two articles by him describing the design and subsequent sailing trials, published in, The Trireme Project, Operational Experience 1987-90 Lessons Learnt and The Trireme Trials 1988, both published by Oxbow books). The rig design featured a large and a small sail and a large and small yard as described in Naval Inventories at the time, although there is apparently no iconographic evidence for a two masted rig in galleys of the last millenium BC. Morrison and Williams  (Greek Oared Warships 900-322BC, Cambridge 1968) poi9nt to evidence that the the main mast was unrigged for battle and the smaller "boat sail" was retained to be used for down wind escape if necessary.

 

The forward mast on Olympias also serves as a useful gantry to raise the much heavier main mast (method described in drawing MSR 13)

 

The sails on Olympias were rigged on a yard hoisted by twin halyards but is unsupported by lifts. As mentioned before the mast is only supported by fore and backstays and has no shrouds (as designed) requiring a substantial tabernacle. The sail is controlled by brails and the downward pressure of these (and the yard braces) is thought to account for the downward curving yards seen in the icongraphy. An illustration of this , for a one masted galley is shown below.(figure taken from The Sailing Rig of Olympias, p30, The Trireme Project, Oxbow Monograph 31)

There are no reef points, as such on the sails. Sail reduction, and furling, is accomplished by brails passing through rings on the leeward side of the sails, and fixed to the foot of the sail. Fore and aft balancing of the rig could be achieved by partly brailing the sail to move the center of effort fore and aft to counter weather or lee helm as required, as shown below (figure also taken from Roberts article in The Trireme Project.) Trials on Olympias also showed that slightly drawing up the middle brails when sailing downwind. Apparently this helps maintain the rectangular shape of the sail, preventing the clews pulling in and spilling the wind out of the bottom of the sail. In the two masted configuration this also helps the airflow over the forward boat sail.

 

Performance on trial suggested that progress could be made to windward with close reaching up to 60 degrees off the wind while making 7 degrees of leeway. In light weather a sailing speed of 2.5 kts could be doubled by light rowing as a bireme (i.e. two top rows of oars only) which would have enabled 1/3 of the crew to rest on passage, even in light winds.

Roberts comments that the main yard on the reconstruction was over engineered and so did not flex in the way sugested by the above illustrations. It was also very heavy, so the original plan to make the halliards from 45mm diameter leather were amended to use 20mm 3 strand polyester rope for safety reasons...

 

Edited September 10 by Richard Braithwaite
additional info and spelling...

[Ian_Grant]

Very interesting!  👍

[Richard Braithwaite]

Completed the yard for the forward mast ("boatyard").  A nice , straightforward, tapered yard 7m long with a maximum diameter of 166mm (full size). Drawing MSR 3 gives diameters at the marked points in the series of photos below to help with the shaping:

 

Edited September 11 by Richard Braithwaite

[Richard Braithwaite]

Shaping of the mainyard, took a bit more thought. Made of two pieces lashed together (like the illustrations in Roberts papers described above), with a relatively more complex transition of section where the two pieces are joined. I havent made yards for a very long time, but I remembered (for this last one at least...) to remark the circumference of the yard at the measurement stations at the point when it is octagonal to act as a guide to help make the faces even when shaving down the vertices to make the yard 16 sided prior to sanding to its final round shape...

Finally a pic of both masts and both yards together, from which it is clear how heavily built the main yard was...

 

[Richard Braithwaite]

Im looking into making all the rigging fittings I need, blocks, deadeyes, fairleads etc.

This page from Davey and Co's catalogue (Products – Davey & Co London Ltd) looks like a good indicator for appropriate block sizes for different rope sizes:

I can also scale from photographs of Olympias, e.g. :

 

 

I havent done any rigging for a very long time... Are there other good sources on block, deadeye etc proportions?

Edited September 16 by Richard Braithwaite

[Thukydides]

I have no knowledge about ancient seafaring practices, but steel gives the ratios for blocks to rope for the late 18th century (https://maritime.org/doc/steel/part5.php#pg153).

[Richard Braithwaite]

Thanks, Thukydides. I looked through Steel a few days ago, and missed that bit...

 

Today Ive been fitting the brace cleats to the  Fore Yard. A bit of careful positioning of the yard and a spacer to make sure they both end up on the same centerline (Image ncludes part of drawing MSR 3  © Estate of John F. Coates, reproduced with permission)...

 

[Richard Braithwaite]

More rigging fittings. Brail fairleads this time. Small (105mm long full size , 4.35 mm at 1:24) bronze fittings defined in drawing MSR 8. 

 

Even working at this large scale, I do get to make some small stuff!

 

They sit on top of both yards and I need 16 of them altogether. I made them on my Unimat in strips of 7 which was the most I could do given the extent of the transverse travel on the milling table...Used my "manual CNC" approach again. Quite a challenge to remember where I was in the sequence right through 7 repeats. I lost one strip because I didnt believe the dial movements ant tried to measure with my vernier guage...Turned out the dial settings were right and the measurement I made wrong...The mounting holes are 0.35mm in diameter and nicely fit some 0.3mm diameter (4mm long) brass pins that I just recieved from Dry-dock Models and Parts.

[Richard Braithwaite]

Ive ordered (and now recieved) ropes made by Ben of Ropes of Scale for this project. Ive gone for polyester tan as a reasonable match for the mixture of Hemp and Polyester rope used on Olympias. I constructed a simple spreadsheet to convert the rigging list (defined in drawing MSR 10) into 1:24 scale and then match against the diameters offered by Ben:

the spreadhseet then sumarises the totals of each rope diameter for ordering:

 

So 47 m in total. As Ben makes these up in 6m lenths I have some margin (varies from size to size...). Whether this is sufficient remains to be seen.

 

First attempt on the model today, lashing the Trierarch's chair to a quarterdeck beam (Image includes part of drawing MSR 26  © Estate of John F. Coates, reproduced with permission). Its very fiddly work, and Im still getting up to speed with it!

In this case I was using Bens 0.35mm rope (equivelent to 8mm full size). I practiced with some sewing thread to work out a suitable method and work out how much rope I needed. When it came to using the polyester rope I whiped one end with Gutterman 120 thread, again very fiddly work. Ive yet to come up with a method for making this go more smoothly...Process then:

1. Start with a clove hitch around both seat and deck beams.

2. pass one more turn around both beams (to match the 3 overall turns shown in the drawing)

3. 3 half hitch turns around the lashing (again to match up with the drawing)

4. I couldnt get in there to whip the final end...so sealed with a drop of CA glue and then cut off.

 

I ended up using a piece of rope 50mm longer than ended up in the lashing (to give me something to hold onto to do the half hitches at the end...) which means a 25% wastage rate for this first effort...

 

Hopefully Ill get better as I go along...

 

Edited Monday at 03:39 PM by Richard Braithwaite