why had some ancient boats such high stem- and sternposts ?

like with the viking ships or Roman galleys or Greek triremes ...
The explanations gathered from "the internet" leave me unconvinced, like: 1/ to impress the enemy 2/ to break high waves 3/ to provide a high lookout 4/ to connect the curving planks at the ends

As these boats were rowed or sailed using a square sail I would have thought it would be important to keep the windage low in particular at the extremities. Mast stays and sail sheets appear to have been connected only at the base of the posts.

 

Perhaps, who could know? knowledge in aerodynamics and hydrodynamics was not, then, as advanced as it is today. Hence, for example, they carried square sails instead of current high performance sails.
Just for venturing an answer.

 

The explanations gathered from "the internet" leave me unconvinced, like: 1/ to impress the enemy 2/ to break high waves 3/ to provide a high lookout 4/ to connect the curving planks at the ends
I would think all of the above are correct. Boats were built before the art of "Spiling" was introduced so the high bow/stern is a result of non-tapered planks.
The high bow is also "impressive". Dugout canoes around the Pacific Rim are sometimes fitted with symbolic 'high' bows.

 

Actually, the simplest explanation is always the best. And anyone who has actually built a historical ship knows that the stem and sternpost are extended to allow the backbone to be braced vertical on the stocks free of the planking runs. Once the backbone (keel, stem, sternpost, deadwood) is fastened, the backbone is erected and then braced plumb. Then the mould frames are erected. The bracing has to be out of the way of the ribbands which will be used to construct the fill frames (Norse and Levant shipbuilding is a bit different as the planks are set before the frames are fitted, but the bracing still needs to be above the planking runs). See The Evolution of the Wooden Ship by Greenhill or photos from any build before the 1930 or modern historical build.
Medieval Histories on Twitter https://twitter.com/i/web/status/859373889138429952

 

What is a source of information about when the art of spiling was introduced?

 

I don't know - perhaps a good book on wooden boat history. My guess, around 1700-1800.

 

Actually way before that time because a ribband was used. See The Evolution of the Wooden Ship by Greenhill.

 

Does Dr. Basil Greenhill tell there about what time the use of ribbands started? The Oxford lexicon dictionary hasn't found the word before 1711, which of course doesn't exclude that the technique was practiced before, and it most probably has started before the word was even invented, otherwise there was no need for the word, or other words for it in other languages...

— ribband (also 'reaband') —
‘‘ Early 18th century; earliest use found in William Sutherland (fl. 1711–1717). From rib + band. Perhaps a folk-etymological alteration of ribbon, compare ribbon and the formal overlap with ribband riband, but it is perhaps more likely that ribbon shows influence from this word. - Verb: Early 19th century; earliest use found in Shipwright's Vade-mecum. ’’

P.S. - about the mentioned William Sutherland's book from 1711: The Ship-Builders Assistant - Just came across one sold for € 512 on catawiki.



P.P.S. - Here's 229 pages (incl. the covers) of William Sutherland's The Ship-Builders Assistant, 1711 — like eg. pic #7 —

You can change the bold red marked 7 near the end of the below URL from 1 to 229 for the page numbers, and change the bold red marked 1600 for the preferred pixel page width.

http://digilib.mpiwg-berlin.mpg.de/digitallibrary/servlet/Scaler?fn=/permanent/library/AE4UUGBR/pageimg&pn=7&dw=1600

 

Weather the term used by the builders was "ribband" is a moot point, however as stated in Boats of the World: From the Stone Age to Medieval Times by Sean McGrail "ribbands" were most likely used to fair the hull of the "Blackfriars" I ship (Blackfriars Ships - Wikipedia https://en.wikipedia.org/wiki/Blackfriars_Ships) dated circa 2nd century CE. If you use a ribband to fair the frames you can easily pick up the plank spiling. Spiling certainly existed by the 12th century CE as hulcs had spiled planks.

 

Thanks for the info John, and as a serendipity "ribband" also brought me the 1711 book by William Sutherland, which I've added in some stages in a P.S. and a P.P.S. to post #8.

 

A convincing theory for me is that, because these ships were sailed primarily downwind, the biggest waves they were likely to encounter would be from astern. Also--just like today--copying was rampant. So when one made a ship a certain way, and it was successful others copied it. The lookout theory also seems convincing to me. Another reason may be when rams were added to galleys (sometime during ancient Egyptian times) there was no reason to build a high, upsweeping bow.

 

The high stern and bow castles gave an advantage point to archers; later riflemen and cannoneers.

 

Thank you for participating in this discussion.

When archaeologists sufficiently uncover the scope of technology, material, resources, utility et al about an era or historical man-made objects there is often awe at the ingenuity and perseverance of our ancestors. While we enjoy rapid waves of technology innovation like during the last century our ancestors had easily a handful of centuries of experience with the same tried and tested technology and reached most likely the best economy of use given the historical context.

For certain, man had experience with the effect of wind catching a mat while standing on a floating log for at least 10.000 years but only 1970's technology allowed the "invention" of windsurfing.

So somehow the high stem- and stern posts must have been worth it for centuries. Particularly for boats I find it hard to believe that they would accept handicaps in handling a ship just for ornamental or reasons of mere traditions.

Using the posts to hold the frame during construction is a clever observation. But I would think they would have sawn them off once built and not useful for managing the boat on the water.

Using the posts as observation points would have generated reports about pegs and/or steps found in the posts of these ancient ships.

For breaking waves I would think the posts in like viking ships are way too narrow to provide much shelter.

Extending the surface of planks to come together at the ends and make a sturdier join does make sense and could explain the curve up determined by the lowest and thus most vulnerable planks. But still the height of the posts for that reason alone seems excessive.

And maybe the windage was not that bad given that posts on both ends balance out ?

It should be easy enough to test. Anybody with experience sailing a viking ship replica ?

 

This terrific film of Draken Haralde Harfagre sailing in storm conditions may offer some insights. Interesting to note how well the hull rides up over the waves, including following seas, the comparatively low freeboard and thus low windage (no superstructure), the height of the wetted point on the bow, the water breaking over the boat on the quarter and the bow (not the stem or stern, but the helmsman still seems to catch it) when close hauled, the finishing of the planking high into the stem, and of course, the terrifying (and beautiful) dragon's head!

 

maybe they ran a rope from high bow/stern to mast (or from bow to stern if no mast) for a tent ridge-line.

I wouldn't underestimate the desire to have at least a tent with headroom if stuck being outside in changing weather for extended time.

On the video the girl mentioned looking out for icebergs, but I've never heard or seen of any provision to post a lookout up on a high prow. Never seen anything that would indicate they were used by archers, etc. You expect a well designed system of foot and other "holds". Something to brace your legs so upper body is mobile.