Coventry Boatbuilders and Sustainability

 

The Use of Sustainable Timbers in Boatbuilding.

 

(This Article was originally published in Classic Boat Magazine by Malcolm Adkins co. director of Coventry Boatbuilders and Chandlery)

 

This article is about using sustainable timber in boatbuilding. It is designed for the small and amateur boatbuilder. The question of sustainability is fraught with difficulties but let us start with a definition. By sustainable we means that the amount of timber that is used over a period - say a year, is not greater than the bio mass of timber that is grown in that period. Now there are problems with that definition. Overall, for example, the UK may grow more timber than it uses (of course it doesn't) but if that timber is predominately Sycamore then that doesn't help boatbuilders (or most other users of timber for that matter). We may think that Larch is grown widely and that therefore a Larch Tree used for a boat will be replaced by new growth. However Boatskin Larches with their clear, knot free grain, have to be up to 100 years old to get the size needed and they have been properly managed in their youth. The practice of forestry management is to harvest at about 50 years. Therefore our Larches are not sustainable. The same applies to Oaks and practically any other timber that we care to name, unless we are using Spruce saplings for our masts and spars. (I presume that the bamboo poles for masts and spars that we are selling more of now, comes from sustainable sources, as it grows so quickly). So in our definition of sustainablity we need to ask questions about the types of timber that we use.

 

History of Timber Use in Boatbuilding:

 

Traditional timbers for boats before substantial amounts of timber were imported would have been Oak and Elm for the centreline timbers. Elm is not a durable timber unless it is constantly wetted and so tended to be used for keels and garboards. Often, as with the Norfolk Broads Wherries the whole boat - centreline, frames and planking would be from oak, indeed oak is the indigenous (British) timber that is most suited to Boatbuilding. Frames were almost always made from oak - whether they were steamed, sawn or cut from compass timber. From the softwoods larch and white pine were used for planking.

With the development of Empire and the ability to import large amounts of timber from client states the situation changed. Timber could now be imported directly often in the process driving species into commercial extinction - Honduras Mahogany and Yellow Pine were examples. Also exotic timbers were grown on English estates - such as the varieties of cedar.

By the Victorian era the range of timbers being used for both small and large boats had increased. Neison - in Practical Boatbuilding for Amateurs (c.1880's) lists - Elm, English or Canadian for keels, with American Elm being used for steamed ribs. (We got some American Elm recently for the restoration of an Uffa Fox International 14 and can confirm that it will bend to tight curves without steam.) Spruce used for light skiffs which stands water well and is light and elastic. Larch is much the same but far more durable and elastic. Mahogany especially American is listed as is Oak . Red Pine is said to be durable and elastic, but heavy and White Pine is good for light skiffs and canoes. Pitch Pine is another good timber and Teak is listed as being most suitable for planking carvel boats of any size. Lastly Cedar is listed as good for canoes although prone to splitting and quite soft. White or American Cedar is more robust however.

So from the Victorian era we get a mixture of indigenous and imported timbers being used. Since that time there has been a constant denudation of timber stocks both here and abroad so that boat builders have had to switch to new timbers. However there does appear to be some element of fashion to this and probably some options are being ignored.

 

Current Practice:

The Lowestoft Boatbuilding Training Centre confirms that they still use oak when they can. However timber crooks are difficult to get, especially in larger sweeps. This is because timber merchants are not geared to the rather specialist tree felling and cutting that is needed for crooks. Barchards in Hull still have some crooks, as do Whitmores near Leicester. Altham Hardwoods specialise in them. Barchards can also do small fresh cut logs suitable for steamed timbers. Otherwise for centreline timbers Iroko (Central and West Africa), Opepe (W.Africa) and Afromosia (West Africa - Ghana) are used. When using exotics for curved timbers lamination techniques must of course be used.

For Planking Iroko or Larch appear to be popular and for fitting out ply, mahogany or timbers such as American White Oak. Cedar can be used for planking (and is of course used for strip planking). For spars Spruce is a good timber but only comes in quite short lengths. Douglas Fir and Columbian Pine come in good enough lengths. North America claims to be sustainable in timber production.

 

Using Locally Grown Timbers:

The advantage of using locally grown timbers is that we can try as customers to put some pressure on suppliers about sustainability which may have some impact, with an importer the line of communication is probably just too long. We are also saving on transport costs and helping our local economies. From a good local yard you get far better help and advice and an ability to cut to order.

If we do get timber locally though, then a different approach to timber is needed. Firstly space is needed for seasoning if you timber is cut green . This means stacking and air drying, and possible at a later stage kilning the wood . It also means some anticipation of use as you must remember that a 1" thickness of timber will take a year to air dry.

From our own experience it does seem that there are alternatives to the imported timbers if the boatbuilder is prepared to search. There are timber merchants who deal specially with Boatbuilding timber (see table 1) and these should be approached.

In this list we have not mentioned the small independent woodyards that still exist. They are often surprisingly good at selecting out what you want. Our local timber mill in the Midlands has produced recently an excellent log of boatskin larch and good boards of oak for steam bending. They have also produced some very good logs of Corsican Pine which is to be used fro a cross section of a Greek Trireme that we are building for the Henley Rowing Museum. .

One option is to do your own milling. Particularly on farms logs are felled in out of the way spots so that milling on the spot is the only option. Trimming with a chainsaw is one option to get a baulk that can be hauled out for sawing later. You will need a big 24" saw with a ripping chain for this. There is portable mill called the Wood Mizer which can handle quite sizeable logs.

TABLE 1 - Timber Yards Specialising in Home Grown Timbers

TIMBER YARD

TELEPHONE

LOCATION

TYPES OF TIMBER

F.A.Aldridge

01953 887415

Norfolk

English Hardwoods

Barchards

Hull

01482 633388

Larch, Oak, Oak for steaming, Oak Crooks

Coombes Boatyard

West Sussex

01243 573194

European Larch

English Woodlands Timber

Norwich, Devon, W.Sussex

01953 887766

Oak, Ash, Beech, Lime, Poplar, Walnut, Cherry, some Apple. Thinks that a lot of replanting is going on.

Lawsons

Liverpool

01704 893998

Reclaimed Pitch Pine and Larch

Paul Martin

East Sussex

01580 830267

Mainly oak boards and compass oak. Has own woodland which is managed on a sustainable basis

Whitmores Timber

Leicestershire

01455 209120

Most English Hardwoods, specialise in Oak

Timbers to Use:

When recently we built a replica of the Kyrenia ship for the Manchester Museum we found that the Maritime Pine that the Greeks planked with had excellent bending qualities. When we switched to Douglas Fir for the topsides we found that timber to be far inferior so far as fitting was concerned. Maritime Pine grows in this country and is similar to Corsican Pine, yet I have not heard of it as a standard Boatbuilding material.

For planking we have a variety of choices. Larch is an obvious timber, although it is not always easy to finish as its' grain tends to rise. There are the British softwoods, Douglas Fir is one possibility that is moderately durable, although it does not bend that easily, Scots Pine or Redwood is widely available, although classed as non-durable. The other softwood that can be used is Spruce, again it is classed as non-durable, but can be obtained with clear grain. Sitka Spruce is the type to look for. Cedar is an attractive timber and can be obtained in reasonable dimensions, in this country Port Orford Cedar is grown as Lawsons Cypress, it does not bend well but is classed as durable, Western Red Cedar is another possible variety. Of the hardwoods we have a choice between oak, which used to be a popular planking, Elm which is no longer generally available and which is not regarded as durable above the waterline, and Chestnut. Chestnut (sweet, not horse) is an interesting wood that is sufficiently durable for planking purposes.

When it comes to planking we should remember that a non-durable timber that may be inadvisable to use in a large boat might be used for an open boat where it is well ventilated. In addition modern timber treatments can increase durability.

The loss of our Elms was a great tragedy as these grew extensively and they were excellent for keels and garboards. Ash is a timber that although is extremely non durable in fresh water lasts well in salt and so can be used for seagoing small boats mainly for framing. Getting grown oak for stemposts, thwart knees etc. is a problem now. Cutting knees from roots of felled trees might be a possibility. Cutting and trimming can be done with a chainsaw. Again oak is the traditional material although you might experiment with hedgerow trees that tend to produce good crooks. There is a lot more that could be done with timber that is regularly cut. Orchards are grubbed out for a number of reasons, often because the trees are exhausted and need to be replanted. Modern Orchard tree varieties are small in size but older ones are not. Apple is a source of crooks for dinghy knees which could be used. Similarly hawthorn can yield large enough knees for dinghies.

I personally do not like the idea of laminating. Assuming that modern glues will stand up to the job over time, there is still a lot of work involved that you don't have with solid pieces of wood.

 

TABLE 2 - English Timbers Suitable for Boatbuilding

TYPE OF TIMBER

DURABILITY

USE

COMMENTS

Maple (soft and rock)

Non Durable

Carving, internal work.

Rock maple bends well.

Sycamore

Perishable

Internal Work

Clear timber bends well.

Chestnut (Sweet)

Durable

Planking

Cleaves well. Needs support on inner face for bending

Birch

Perishable

Internal Work

Robinia (False Accacia)

Durable

Unknown, but possibly planking.

Good bending properties. Heavy and tough.

Hawthorne

Unknown

Knees, blocks, cleats, thole pins

Hedgerow trimmings

Ash

Perishable

Frames (salt water), oars, blocks

Bends well, light weight with outstanding toughness.

Holly

Perishable

Blocks, cleats, thole pins, tool handles.

A very hard wood.

Walnut

Moderately durable

Internal work, decorative

Bends well, but very scarce.

Apple (& other Fruits)

Unknown

Knees, blocks, cleats, etc

Distorts on drying. Small sizes

Plane Tree

Perishable

Decorative internal

Oak

Durable

Centreline, planking, framing.

Bends well, needs support, will stain in contact with iron or steel.

Lime

Perishable

Carving

Elm

Non Durable

Keels, garboards, (underwater)

Uncertain availability

Larch

Mod. Durable

Planking, fitting out

Cedar

Durable

Planking, fitting out

Tends to be soft and brittle

Douglas Fir

Mod. durable

Planking, decks, spars

Pitch Pine

Mod. Durable

Planking, fitting out

Corsican Pine

Non Durable

Planking

Needs to be treated, may discolour

Maritime Pine

Mod Durable

Planking

Scots Pine - Redwood

Non Durable

Planking, spars, oars

Needs to be treated.

Port Orford Cedar - (Lawsons Cypress)

Durable

Planking,fitting out, oars, paddles

Similar to Douglas Fir

European Spruce

Non Durable

Masts and spars, oars

Needs to be treated

Sitka Spruce

Non Durable

Planking

Needs to be treated

Western Red Cedar

Durable

Planking, fitting out

Accelerates corrosion of metals

Yew

Durable

Unknown

Bends well, durable, but small supply.

What Can We Do?

Although we may use home grown timbers we can still not guarantee sustainability. Indeed it is a moot point whether switching to less common timbers - for example Sweet Chestnut, will hasten their removal or encourage them to be included in planting policies. To get sustainability we do need a replanting policy that will produce the types of timber that we need. By using boat skin larch we are in fact denuding our supplies of 100 year larch, just as surely as the West Africans are denuding their Iroko, if we do not manage timber on a sustainable basis. I have wondered for some years if it would be possible to identify a number of regional yards that would make sure that there were crooks and curved timbers and other suitable boatbuilding timbers available. Done in conjunction with the increasing amount of building conservation work that has similar demands it might be possible to advertise such places. These yards would have to work in conjunction with suppliers who managed their woods and forests on a sustainable basis. Similarly pressure needs to be put on a number of estates to leave some trees for the longer growing times that our timbers need. There are possibilities. For example the National Trust have extensive properties and might be encouraged to manage sustainable timber production. Many local authorities have extensive areas of parks, gardens and estates, school playing fields, roadsides. And maybe there is some direct action you can take. If you use a tree why not plant two or three to replace it somewhere where you know they will survive. This is for the future.

 

Malcolm Adkins, Coventry Boatbuilders and Chandlery - Tel/Fax +44 (0) 2476 256 061.

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