"Sailing Speed" Topic

From Wikipedia:

"A total of fifty-nine French sailing frigates were built between 1777 and 1790, with a standard design averaging a hull length of 135 ft (41 m) and an average draught of 13 ft (4.0 m). The new frigates recorded sailing speeds of up to 14 knots (26 km/h; 16 mph), significantly faster than their predecessor vessels."

How fast were the larger ships?

link

The limit for a displacement hull is 1.34 x square root of waterline length, i.e. for a 100' long vessel you cannot go faster than 13.4kts. Note that for wooden ships in the age of sail you can't go much above 180' without the vessel becoming significantly hog backed.

Todd – Nice little chart to see

I'd be interested to learn the source and underlying explanatory detail of the speed values given on the "3decks" webpage. I've expended a very good deal of time and effort in the study of speed capabilities of warships in the Age of Sail. Believe me when I say that it is a complicated subject indeed – both in terms of "maximum" speeds and speeds achievable under differing conditions of wind, sea state and point of sailing.

It has generally been posited that the fastest sailing frigate in the era of sail was HMS Endymion, which was credited with 14 knots during the period in which she was carrying 18-lbrs on her gun deck. USS President was said to have achieved 13.5 knots in a topgallant gale. These were considered noteworthy achievements. The typical speed of a British frigate of Napoleonic War vintage was about 12 knots; any better than 12 knots was considered fast; there were also frigates unable to make 12 knots. Robert Gardiner's various works on British frigates are useful on this topic.

As for "modern" Napoleonic era three-deckers, 9-10 knots was by no means out of the realm of possibility. Old and old, worn out three-deckers could however be noteworthy dogs; one such ship (HMS Glory, IIRC) was said to have been unable to make better than 7 knots.

To further complicate matters, DK Brown wrote an analytical essay on speed of sailing ships and very strenuously argued that any speed reports from the sail era should be treated with care, as they were probably optimistic by about ten percent.

There is so much to this subject, it deserves an essay.

B

Hi Lascaris – re risk of hogging (and sagging) you are correct – up to the turn of the 19th century, when diagonal bracing was introduced. This design development enabled construction of huge three-deckers which ultimately reached waterline lengths respectably in excess of 200 feet. HMS Victoria (1859), of wooden construction but fitted with cast iron "riders", was 260 feet on the waterline.

FWIW.

B

Thanks Blutarski! I wasn't aware that diagonal bracing extended the length you could make a wooden ship rigid by such a large extent. Nice to learn something :)

Wise words from Blutarski there. Also worth noting that the length related "maximum speed" isn't, it's just a speed at which the resistance of a particular length of hull increases. A quick survey of high speed displacement designs will show that "maximum" exceeded on a routine basis

Wrt an essay, didn't Rif Winfield write something along those lines, or has my addled brain confused this with something else?

David Manley for high speed displacement hulls don't they require lightweight/high HP engines to realize? I don't think you can exceed hull speed with sails for propulsion or, if so, I haven't found a reference for doing that.

Try finding enough wind in the summer off the US east coast to get anywhere near hull speed!

USS Constitution's log noted 14 knts over an hour at one point. Not really helpful because it was not a sustained speed over time and could have been an overestimation.

I don't think you can exceed hull speed with sails for propulsion or, if so, I haven't found a reference for doing that.

link

VSB, Exceeding the nominal LWL hull speed due to lengthening the actual effective waterline length through heeling or overhang designs will make the maximum speed higher, although it's still constrained by the length of hull at the waterline. Designing a flat bottomed displacement hull that can go up on a plane also is not exactly a displacement hull like an age of sail vessel. For the link's last point that boats can exceed hull speed, very temporarily, when surfing down a wave face while running downwind is true, although it's of a very short duration and you cannot maintain an average speed over hull speed.

Dave Manley is far better informed on the topic of naval architecture than I; I hope he will be kind enough to correct any errors of fact or logic that might appear in what follows.

Length of hull is not the sole determinant of the ultimate speed capability of any given ship design. Another very important factor is tonnage versus hull length. The good Jean Boudriot was kind enough to provide tabulated particulars of dimensions and weights for the standard classes of French sailing warships circa 1780 in his magisterial four volume work, "The 74 Gun Ship". An important data point provided by Boudriot is the actual displacement tonnage of each ship type. In other words, Boudriot tells us what the vessel actually weighed (as opposed to the British or American "burthen tonnage" which is really a more or less arbitrary builder's formula that bears no real relation to a vessel's displacement/weight.

I'm too lazy to convert to English weights and measures, so quote verbatim from Boudriot (Vol III, p.259) in metrics:

> Hull dimensions = hull length x beam x average draft.

> Displacement tonnage reflects the subject ship fully fitted out and stowed with 6 months provisions:

Ship Type – – – – Hull Dimensions (M)- – – Displacement (MT)
110 gun 3-decks – 62.30 x 16.25 x 7.80 – – 4,666
80 gun 2-decker – 56.22 x 15.27 x 6.82 – – 3,620
74 gun 2-decker – 52.65 x 13.97 x 6.17 – – 2,925
12-lbr frigate- – 43.87 x 11.05 x 4.55 – – 1,166
20 gun sloop- – – 31.19 x 8.45 x 3.73- – – 564

- – -

If we divide displacement by hull length, the following values are obtained -

Ship Type – – – – tons per meter of hull length
110 gun 3-decks – 74.9
80 gun 2-decker – 64.4
74 gun 2-decker – 55.6
12-lbr frigate- – 26.6
20 gun sloop- – – 18.1

- – -

If we assign a ratio values to the tons per meter of hull length, the following relative ratios emerge (using a reference ratio of 1.0 to the 74-gun 2-decker) -

110 gun 3-decks – 1.35
80 gun 2-decker – 1.16
74 gun 2-decker – 1.00 <reference value>
12-lbr frigate- – 0.49
20 gun sloop- – – 0.33

- which should approximately correspond (if my logic is correct) to the ratios of relative areas of transverse midships cross-sections of the hulls of these ships.

The cross-sectional area of the 110 gun 3-decker is one-third greater than that of the 74-gun 2-decker; the 12-lbr frigate is one-half, and the 20 gun sloop one-third. The greater the equivalent flat-plate area, the more power is required to move it through the water. In addition, the longer, wider and deeper the hull, the greater the underwater hull area offering frictional resistance. On the other hand, the smaller the ship, the less sail area she can carry and the less stability she can offer to contest wind forces.

I hope I have this reasonably (fundamentally) correct. Anything more complicated I must leave to a more qualified authority.

FWIW.

B

Very well done!

The one thing often noted in the history of Age of Sail ships is that a well trimmed and managed 74 could often overhaul a frigate or other smaller ship in heavy weather.

The larger ships tended to be built more solidly, as their hulls could support more load (by nature) and, at least in the case of English ships, this allowed them to handle more canvas in heavier weather.

It's been claimed that French ships were more lightly built compared to English or Spanish ships and could not be handled as well in rough conditions…

I think there was also the quality of the timber available to the various navies – the British and Americans had access to superior material – must have had an influence on sailing speeds.

Blutarski, do the displacement values in your chart
presume a standard armament for the different classes
about which you've posted ? Or would the weight of the
guns with which a ship was armed not make that big a
difference ?

I'd thought there was, at least in the RN, a deal of
experimentation during the first decade or so of C19.
especially the arming of some ships almost exclusively
with carronades.

Come to think on it, USN experimented also (USS Essex
comes to mind).

Hi Ed,

Boudriot's chart stipulated that the total tonnage figure for each ship represented it in a fully fitted-out state, which included: anchors, guns and ordnance stores, boats, crew and their personal effects, iron and shingle ballast, victuals and provisions for six months. In typical OCD French researcher fashion, Boudriot even provided specific tonnages figures for each of the afore-mentioned categories.

The RN indeed had a long and extensive period of armament experimentation and development. First was the carronade, whose impact was most deeply felt (at first) among the smaller classes: post-ships, sloops, brigs, etc, whereby many if not most such ships had their old light caliber long gun batteries replaced wholesale: a 6-lbr long gun could be replaced one-for-one by an 18-lbr carronade; a 9-lbr long gun by a 24-lbr or 32-lbr carronade. Another feature appreciated by the RN was that the carronades required fewer men to serve them than were required by the old long guns they replaced. This trend among the light ships blossomed during the latter part of the AWI. Frigates and ship of the line during this AWI period typically added small number of carronades to forecastle and poop. It was not until the latter part of the French Revolution and Napoleonic War period that carronades really began to appear in increasingly large numbers on frigates and ships of the line, usually as a consequence of light weather deck long guns being replaced by carronades. Interestingly enough, even by the late Napoleonic War period there were still considerable numbers of old ships of the line lacking carronades; it was the new constructions that seemed to get the big carronade outfits.

Another much less well known and rather under-appreciated phenomenon was the introduction of "medium weight" long guns aboard ships of the line. These were still nominally "long guns", but somewhat shorter in length and lighter in weight than conventional long guns. Congreve, Blomefield and Gover were designers and manufacturer of these medium-weight weapons. They were fitted to old and tired ships structurally no longer able to carry their original designed armament; a good example is HMS Gibraltar – 2-decker Spanish 80 built in 1749, captured by GB in 1780, still in RN service in 1812/13!

God and "Miss Florence" willing, we will see each other next week at Southern Front. We can blab at more length then. Hope you will be able to participate in one of my AoS games!

B

Question of the group, what does Chapelle say about this in
"The Search for Speed Under Sail, 1700-1855"? I don't have a copy.

Do watch out for "Miss Florence" B – run before the wind, if you have to!

Hi pvernon -
I do have both of Chapelle's better known books, "The Search for Speed under Sail" and "The History of the American Sailing Navy", but it has been ages since I cracked either one of them. From dim memory, I do not recall him discussing ships of war in "Search for Speed", to any great extent; most of the book seemed to focus upon small/fast merchant ships and tthe clipper ship phenomenon.

Maybe I should re-visit Mr Chapelle …..

B

At my age, starcruiser, I might just choose to "lay to" and ride it out.

:-)

B

Ah, the wisdom of age…

It's a rough storm but, it's already much weaker than expected so, why not?

Red Trotsy Red,

I think the quality of the timber primarily related to its propendency to splinter & hence be more dangerous in battle. Not sure it related to sailing speed.

Hi OG – Fir indeed had a reputation for a high degree of splintering when struck by shot.

Fir's only contribution to speed I could visualize is that its density was rather less than that of oak; a fir-built ship would therefore presumably confer some weight advantage, depending upon the amount of fir incorporated into the hull.

FWIW.

B

A friendly, encouraging and hopeful reminder to all folks planning to attend the Southern Front wargaming convention this coming weekend in Raleigh NC. I will be running Age of Sail games Friday, Saturday and Sunday.

B

On timber and sailing speed -- there are degrees of quality of oak, as well as how it is treated, how much time there is to season it, and so forth, that do affect the joins and the porosity of the hull.

Fir is a softwood, oak is a hardwood. My impression is that fir built ships were considered second best, because the less dense wood more quickly becomes waterlogged, therefore slow. The British built cruisers in softwood only when they felt threatened by the USA's capable fleet being added to the sheer number of Napoleon's ships.

A belated response to the link from 3decks: this seems like the breakdown of unit speeds in a wargame, where a step bigger is always a step slower. In fact the frigates were often only faster than a good liner by 2-3 knots. That difference would tell in a chase, but it would be harder to notice in a maneuvering action or a battle constrained by keeping station or by operating in an estuary. I picture ships in these battles as traveling at the speed of lawnmowers. The ability to get underway quickly after a gap was probably more important than chase speed, in that context.

Arguably, physical design for speed reaches a plateau after which crew quality is the biggest variable, as it is in a regatta. An experienced crew that knew how to load their ship so she wasn't dragging either her prow or her stern could probably outrun a "faster" but poorly laden ship.

ps 2 Blutarski -- I hope that someday I'll be in the SE United States when you're running one of those games. Fair skies to you & everyone in that region.

One more thought -- suppose you were designing a game about close combat between ground vehicles, and you learned that one of these vehicles was faster that the others by 3.5 MPH / 5.5 KPH, maybe even a little more. Would you consider that speed difference worth translating into the reduced scale of a game? 'Cause that's the amount of speed difference we're talking about, in many cases, and that's after several other profound variables are factored out.

Hi Cursd Captain -
I'd be more than pleased to have you in a game! Anytime.

B