A Simple Guide to Features & Terminology of a Thames Barge


Repertor at Seasalter

Repertor off Seasalter with Decima in the background

As a kid, I played on the Whitstable quaysides overlooking the barges but, as a landlubber with no maritime relatives, I never actually got to learn from practical experience or from the stories of seamen. Furthermore, as a bit of a ragamuffin with no academic interest at that stage, I was never tempted to pick up a book or visit a library. The Thames barge was simply something people worked on if they didn't work in a factory, shop or office.

Academia, fascination and nostalgia came much later but they came with problems. At the outset, I found it quite difficult to locate explanations that didn't assume that I knew something already... and I couldn't know something already until I had learned something already....  from somewhere!

So, to prevent other landlubbers from getting something of a headache, I have decided that our Thames Barge section needs a brief and simple introduction to the Thames barge. I have also decided that it would be as well for someone simple to write it. After all, the best person to know what a simple person doesn't know is a simple person who knows slightly more. Thus, I have offered my services.... and relied on information supplied by our knowledgeable readers.

It is not my intention to supply a fully comprehensive guide to the Thames Barge. That would be beyond the scope of both our small feature and me. However, I do hope that these scribblings will encourage some of our visitors to delve deeper into the fascinating world of the barge via the many more sophisticated sites available on the web.

First.... A Word on Variations

Before we start, let me warn about variations. Whilst you may be comfortable spotting a broad "Thames Sailing Barge look", you must remember that boatbuilders didn't have one master blueprint stashed in a drawer that they used over the centuries. There were many variations on the basic theme and those variations stemmed from a number of very different factors...

  1. Barge design evolved gradually and it took into account practical experience, new ideas and improvements in technology. Some design changes were incorporated into the creation of new vessels. Others were added later as part of the conversion or modernisation of existing craft.
  2. Barges were designed for the specific waters in which they would operate. Even within the relatively limited scope of South East England, these could vary greatly between river, coastal and even deep sea routes
  3. Designs might be created to meet the requirements of specific types of cargo. Existing craft were also modified when their function and/or ownership changed.

The end result is a complicated picture and one that we will only partly unravel here because we will be sticking to the set ups that you can still spot today rather than ploughing back into the very early and less efficient designs of the distant past. However, don't be surprised if you stumble across old drawings of rather different and somewhat cruder craft from earlier years.

So... Where Should We Begin?

All this makes it difficult to know where to start. However, I have decided to stick close to home by looking primarily at one particular local barge - Steve Norris's staysail barge Greta. I will then broaden the discussion to other possibilities.

There are a number of reasons for choosing Greta. Firstly, it is a classic barge that has been beautifully restored. Secondly, you can take a close look at it in real life because it is often berthed at the south quay of Whitstable harbour. Thirdly, you have the opportunity to sail on her because Steve offers trips and charter opportunities.

 Finally, thanks to Peter Dalrymple, we have some wonderful photos of the vessel to work with in producing this guide!

Sails of a Thames Barge

An Overview

The sails are one of the distinguishing features of a Thames barge but there are a fair number of variations. For now, let's just stick with Greta and consider an overview of some of the main sail components and terminology....

The sails of the Greta - a typical "stay sail" barge

The sails of the Greta - a typical "stay sail" barge

I have always followed a basic principle when it comes to explanations. As far as I am concerned, complex things are usually just lots of simple things joined together. The first move isn't to understand the complex. It is to identify the simple. Thus, our next step is to examine each of the main elements of the barge..... starting with....

The Masts

The traditional Thames sailing barge has two basic masts as far as we landlubbers are concerned! However, these give rise to three mast names!

The masts of the Greta

The masts of the Greta

The main mast is set slightly towards the bow. It also comes in two separate and overlapping pieces. The lower piece grabs the title main mast and the upper section is fobbed off with the less grand title of "top mast". A separate mizzen mast is located at the stern.

Sails of the Main Mast

Attached to the rear (ie "aft") of the main mast is the main sail and this has a set up that typifies so many Thames sailing barges that we see today. Take a look at an extract (see below) from our labelled photo of the Greta .

The main sail with its diagonal 'sprit' spar

Right: The main sail with its diagonal 'sprit' spar... but no 'boom'

Photo by Peter Dalrymple

Notice that the main sail has a diagonal wooden spar stretching from the lower section of the main mast to the upper corner of the sail. This is known as a sprit.... hence the terms spritsail and spritsail barge. The sprit is set at approximately 30 degrees to the mast and rotates horizontally in order to take up the best position in the prevailing wind.

The sail doesn't have or need a boom along its bottom edge. It simply hangs loose. (Note for total landlubbers: A boom is a wooden pole/spar that, on some other types of sailing vessel, stretches horizontally along the bottom edge of a sail from the mast . It is usually the thing that swings round and knocks actors into the water in comedy films).

Below, John Harman explains the when and why of the spritsail idea.....

After a period of development in shape of hulls and rig, the barges that finished their working years were 'Spritsail Barges'. This refers to that large 'mainsail' held out on that large spar called a 'sprit'.

This sail was developed for ease of handling by one man. It does not have to be lowered but can be quickly bunched (brailed) against the mast, by hauling on a brailing line.

John Harman

John's comments remind us of something that we mentioned on our Barge History Page. For reasons of economics, barges were designed so that they could be sailed by a crew of just two people - the skipper and his mate. By coincidence, the America's Cup was being screened at the time of drafting this article and it was interesting to compare the crew of a barge with the hoards of people required to sail a racing craft.

The brailing of the sail can be seen in the photo kindly supplied by Ann Nash below....

Barges at Whitstable harbour with main sails brailled against the mast

Barges at Whitstable harbour with main sails brailled against the mast
Photo with thanks to Ann Nash

In effect, the sail was like a posh curtain that could be drawn up when not required. The brailing process was helped by the fact that that there was no boom holding the bottom edge of the sail. The absence of a boom also meant that there was easy access to the main cargo hatch once the sail had been brailed. This was important because the main sail was directly above the main hold of a Thames Barge.

In port, the sprit had another purpose..... as a form of "on-board" crane. One very odd deployment of this facility is described by John Harman on our Harbour Operations page.

That's the main sail dealt with. Now we move to the other side of the main mast. Attached to the front of this is a triangular foresail that stretches to the bow of the barge - see below.

The foresail of the Greta

Right: The foresail of the Greta -  a triangle stretching from the main mast to the bow of the barge

Photo by Peter Dalrymple

Sails of the Top Mast

The top mast provides for further sails to be fitted immediately above those of the main mast. It is joined to the main mast as shown below.....

Top mast

Left: Top mast - an extension of the main mast that enables extra sails to be deployed

Photo by Peter Dalrymple

At the rear of the the top mast, we have the aptly named topsail - often spelt and pronounced as top s'l. At first glance, this appears to be triangular in shape but closer inspection shows that it actually has four sides.....

The 'four-sided'  top sail

Left: The 'four-sided'  top sail

Photo by Peter Dalrymple

In front (ie forward) of the topsail of the Greta, we have a triangular staysail....

The stay sail

Left: The stay sail... stretching from the top mast to the bow

Photo by Peter Dalrymple

This is attached to a stay that stretches from the top of the mast to the bow of the barge.

The Staysail Barge

Here we need to take stock and puctuate our explanation because that particular arrangement of the stay sail typifies a category of barge known as a Staysail Barge.... and Greta falls into that category. A little later, we will  look at a common variation - one that will give us our other main category of barge, namely the Bowsprit Barge.

The mizzen sail, mast, sprit and boom

The mizzen sail, mast, sprit and boom

Sail of the Mizzen Mast

The mizzen mast is located at the stern of the vessel and, on a barge, it normally carries just one sail - the mizzen sail (see photo right).

Like the main sail, it has a sprit - known as the mizzen sprit. However, unlike the main sail, the mizzen also has a boom along its bottom edge.

I presume that one of the reasons for this is that the mizzen extends beyond the stern of the vessel. Without a boom, there would be nowhere to attach the far bottom edge of the sail.

The mizzen is located just behind the ship's wheel and it is more a device for assisting steering than providing propulsion.

Sail Combinations...

Sailing vessels don't necessarily deploy all their sails at one time. One of the great things about the design of the Thames barge is that it can operate with almost any combination of its sails to suit the prevailing conditions. Thus, you may spot a vessel operating with anything from one sail to all sails.

Sail Colour

For years, I wondered why barge sails were usually red. Finally, Nigel Robinson cleared it all up....

Sailing barge sails were red due to the substance which was put on them to preserve them – a mixture of linseed oil, red and yellow ochre, and water – so now you know!

Nigel Robinson

It's just as well ochre isn't pink.... otherwise we could have barge skippers eating marmite sailors rather than marmite soldiers.

Common Sail Variations & Additions

The Bowsprit Variation  - The Bowsprit Barge

Some Thames barges have a bowsprit.... and that gives us another category of barge, (the  bowsprit barge), to add to our staysail category. A bowsprit is essentially a pole that stretches almost horizontally from the bow of a vessel and it can be seen in the shot of the Marjorie below...

Bowsprit barge 'Marjorie'

Bowsprit barge 'Marjorie'
Photo by Peter Dalrymple

The bowsprit allows sails to be set further forward (ie beyond the bow of the vessel) and, thus, has more scope and flexibility for sails than a staysail barge. In fact, if you spot a bowsprit barge in full sail, you are likely to detect two sails stretching from the bowsprit -  ie a staysail attached to the top mast and a jib attached to the top of the main mast. We can see this in detail by comparing the bow of the 'Marjorie' with that of a staysail barge. See below.

Comparison of the bows of bowsprit and staysail barges

Left: The bow of the bowsprit barge Marjorie
Right: The bow of the staysail barge Wyvenhoe

In some descriptions of bowsprit barges, I have seen these sails referred to as "upper jib" (rather than staysail) and lower jib (rather than just 'jib'). If someone technical can assure me that there is no technical difference, I prefer this terminology because it means that a bowsprit barge has jibs whereas a staysail barge has a staysail. It would be a whole lot simpler for a simpleton like me!!!


I understand that a staysail (or upper jib) can be set up as a spinnaker. However, as a "know nothing", I am getting myself into deep water here and I will merely add that a spinnaker is a sail that fills with wind and balloons out in front of the vessel. It is primarily used when the barge is sailing down wind.

A Whole Lot of Sail.... and Flexibility

When you take into account all the sail variations and possible additions such as spinnakkers, you realise that a barge can carry an awful lot of sail at times. Take a look at this shot of the Marjorie at the Swale Barge Match....

The bowsprit barge 'Marjorie' in the Swale Barge Match

A whole lot of sail - The bowsprit barge 'Marjorie' in the Swale Barge Match

You also realise that the barge provides a lot of flexibility due to the number of sail combinations available.

Less Common Sail Variations

Gaff Rig Variation and Boomies

If you only have a mast to support sails, sails need to be triangular because there is only one place to attach the top. However, the problem with a triangular sail is that it has a limited surface area.

A "four sided" sail can provide a larger surface area but it needs an extra structure (such as a wooden spar) to be attached at an angle to the mast in order to support the top far corner. In describing the Greta, we have already seen one way that this can be accomplished for both the main sail and mizzen. It involved the use of that "sprit" spar that ran diagonally across the face of the sail from the bottom of the mast to the top far corner.

However, that is not the only option. Another method is to have a spar that runs almost horizontally along the top edge of the sail from the upper part of the mast. This type of spar is known as a gaff. There can be a further spar at the base of the sail - ie the boom. Compare the spritsail arrangement of the Greta's main sail (below left) with a rough diagram of a gaff (below right)...

Comparison of spritsail and gaff rigged sails

Left: The sprit sail arrangement of more recent Thames barges
Rignt: The less common gaff variation

Some Thames barges can be "gaff rigged" on both their mainsail and mizzen. In such cases, the barge may be referred to as a boomie. I would have preferred "gaffer" but the term had already been applied to football managers.

I am told that gaff rigging involves more effort on the part of the crew because the sail needs to be lowered when not in use whereas the spritsail can simply be raised and stored on the mast. As mentioned earlier, the spritsail was a later invention designed to make life easier and keep crew numbers to a minimum. In fact, some older barges were converted from gaff to spritsail in order to improve operations. Nevertheless, gaff rigging continued to be used for some vessels as it performed better than a spritsail in open seas.

A Cross Breed? - The Mulie

With all the various sail options, you may be wondering if these can be mixed. Well, the answer is.... yes.... and that brings us to the mulie. As you know, a mule is cross between a horse and a donkey. In the case of a mulie barge, there is a mixture of sail types that is a little different from the norm. The main sail has a sprit but the mizzen is gaff-rigged. There may also be other differences. The mizzen mast may be much taller and set further forward - in front of the wheel rather than behind it.

Stumpie Variation

Another variation is a barge with no top mast and therefore no topsail. This is known as a stumpie. Stumpies were usually smaller craft and they operated more on rivers than on the coast. The absence of the extra mast and sails was convenient for this type of environment - particularly as they could pass more easily under bridges.

I have never seen a stumpie at Whitstable and I don't have a photograph. However, I can give you an idea of the basic look thanks to a bit of photo editing. Here I switch attention to another surviving barge - Lady of the Lea. The photo on the left below shows her at a Swale Barge Match and, as you will note, she is a staysail barge. On the right, we have 'edited out' her topmast and top sail to show the approximate appearance of a stumpie!

Lady of the Lea with top mast edited out

Above Left: Lady of the Lea
Above Right: The same photo with top mast, topsail and staysail edited out

That stumpie appearance is not one that we see much in modern times and, consequently,  it is perhaps not one that we normally associate with the Thames barge. However, slip back a century or so, and the less glamorous "stumpie" silhouette would have been quite common in and around the city of London. In fact, you may well stumble across old paintings of London that feature such vessels.

The reason that we chose Lady of the Lea for our editing is that she is smaller than other barges featured in our article and, even more appropriately, she was originally stumpie-rigged. She operated in the London area  and I suspect that she may have acquired her name as a result of working the River Lea - an important tributary of the Thames that had links to the national canal network. Her top mast, top sail and stay sail were added later to give her the elegant look on the left.

It is worth noting that a barge with a topsail may be referred to as a tops'l barge. However, a tops'l barge can forego its top mast in which case you may hear it called stumpie-rigged.

Types of Sail Rigging... for Types of Usage...

As I mentioned at the beginning, barges were often designed for specific types of use. Whilst there were no hard and fast rules, stumpies and staysails tended to work locally within the river and estuary whereas bowsprits might venture further afield on coastal voyages or cross channel. Boomies and mulies were true coastal vessels.


We continue our guide to the Thames Barge design on page 2 - with an explanation of leeboards, hulls, steering gear, cargo holds and bobs. Click the page 2 button below.

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