The trouble with timber boats is .... They require regular maintenance


Timber has been used in boat building for several centuries. It is still the preferred construction material for many yards.  A well designed, well built and well maintained timber vessel is a coveted possession.


Discovering problem areas in timber vessels goes hand in hand with longevity of ownership.   

New and existing owners should give the areas listed careful consideration.
Timber, like any construction material can have problems, many of which stem from neglecting regular maintenance. If you are considering purchasing a wooden vessel, or already own one you should be familiar how best to maintain each particular construction type.

 

 
Planking problems  

 

  
Decay in the sheerplank caused by fresh water seeping between the deck the top of the plank under the deck covering. It is found by sounding the plank with the handle of a screwdriver or similar and noting areas of dull sound.

Careful sounding should not cause any damage to the vessel .


Look at the hood ends for any sign of movement that might indicate the hood end fastenings are failing and pulling out, commonly known as a sprung plank.

 
Sounding the hood ends would indicate planks that are not tight to the construction, a tight plank will sound solid, and a sprung a plank will sound hollow.  

The hood ends both fore and aft can suffer with decay because of fresh water absorption into the end grain of the plank. 

The garboard plank is the first plank up from the keel quite often this is the plank that will first show signs of caulking failure. Look for possible evidence of movement in the seams.

 

 

 
Deck problems Stem & Stern

 


Failing deck covering, particularly canvas which allows rainwater to seep into the construction of the deck and cause decay problems.

Any area above waterline where rainwater can collect and penetrate the construction. 
This includes under coachroof cappings, corners of cabin trunking etc.

 
The top part of the stem may occasionally decay because of fresh water absorption into the large area of exposed end grain.

The hidden area under the stemhead fitting is vulnerable to fresh water decay.

Signs of movement caused by “head on” impact. The whole area will have a shaken cracked paint appearance.

The transom outer perimeter can suffer decay where the planks land on the edge.

 

 

 
 Below decks Fastenings & keelbolts

 


Broken or cracked frames, these will often be found at the turn of the bilge particularly at the stern of the vessel and commonly under bilge stringers. The odd broken frame is common and probably not too detrimental provided adjacent frames are all sound. Quite often some of the broken frames will have been broken when built, as is the case with many Folkboats.

Any knuckles or hard corners that show on otherwise fair topsides or bottom planking externally usually indicate a broken frame here.

Occasionally you may come across decay in the keelson of the vessel. The keelson is invariably Oak elm or iroko, and of substantial size and a limited amount of decay probably has little effect provided some curative measures are taken.

However if decay is serious it is likely that the plank fastenings would be unable to hold which ultimately requires the keelson to be replaced. As this is the very first piece of timber created in original construction its replacement is a major task.

 


The majority of timber vessels will have keelbolts; these do require inspection occasionally. Depending on the construction and keel material these will possibly be bronze or ferrous. A high degree of corrosion leaking externally at the position of a keelbolt might suggest this is the one to inspect.

 Don’t forget that the vessel will have other “centreline” bolts, which may also corrode, rust or corrosion staining from other area of the keel, stem and deadwoods may indicate this.

Occasionally sample of the underwater mainframe planking screws or fastenings will require removal for checking. These are the screws (bronze usually) that hold the hood ends and garboard planks in position. (hopefully).

 

 

 
Plywood Common plywood failure areas

 
Plywood may be used for building the coachroof, the deck, cockpit partitioning, bulkheads etc. anywhere where rainwater could have come into contact with plywood has to be a high risk area. This also is tested by sounding and spiking (but only if it's your boat!!)

 

 


Cabin window apertures, the section directly under the window.

Bulkheads, any section close to the outer edges that abut other areas.

Bulkheads, where battens are attached and water has seeped behind.

Bulkheads where any aperture has been pierced.

Plywood decks, where teak has been fitted directly on top. These can be extensive problems if water is allowed to lie between teak and ply.

 

 

 
Unusual Problems  

 
Anodes are thought generally to protect, unfortunately in timber vessels an excess of anodes particularly if wired according to manufacturer's instructions can cause extensive decay to the timber surrounding the anode and the timber surrounding the protected metal such as the stern tube. 

This is because when the anode is successfully protecting the metal, strong alkaline chemicals are formed and these chemicals surround the anode and protected parts and seriously softens the timber. The first sign of this attack is usually a furring similar to that seen on battery connections, on the internal anode fastenings and on the internal end of the stern tube.
Occasionally you'll come across a vessel that has steel floors fitted fastened to the planking with copper rivets.  The SCOD is a particular example of this. Because of the interaction of copper and steel immersed in water, planking in the area of these copper fastenings suffers from electrolytic decay, fastenings are no longer tight in the timber, and the vessel leaks when sailed hard because the planks are moving here. 

This same decay will happen anywhere where two very dissimilar metals are in contact with one another (deliberately and accidentally) and used as timber fastenings.

 

 

 

 
The dark areas Masts

 
Any areas of the vessel which do not have good ventilation are always suspect, the usual areas are the stern cockpit locker and all the construction and deck beams here, and occasionally the galley area where fresh water leaks from the galley sink has caused decay.

 

 


Hollow box section timber masts may have glue line failure, on the varnished mast it is easy to see, often the failure is the result of deterioration of the early glues used in the construction. Provided early action is taken to prevent further failure it needn't be too catastrophic. Quite often splines can be fitted in a section of glue line failure

The base of the mast can suffer from decay, whether it is deck stepped or keel stepped, it can still be like a fence post in the ground !!!

 

The above listed items might be considered things to look out for on your own wooden boat or one you may be purchasing. The list isn't designed to be comprehensive, but it should help in a primary appraisal of the vessel before going to the expense of a surveyor.  John Lilley

 

 

 

 

 

 

 

 

 

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