BS1088 Information

Below is some general information on BS1088 plywood.  It is important when buying timber for your project that you are informed about what you are purchasing so you end up with the best products for your boat.
For those looking to build a boat using marine plywood in Australia there are a number of options to choose from but not many in the lightweight category.  The choice of many boat builders for years has been a ply made from an African hardwoood called Okoume or Gaboon. 


What exactly is Gaboon marine ply?

Gaboon or Okoume (Aucoumea klaineana) is a medium sized hardwood native to equatorial West Africa.  Its major use is in the production of plywood.  In its plywood form it has been used extensively in boat building and is still used in the manufacture of lightweight aircraft.  Gaboon is one of the species that can be used to make lightweight marine ply under the British Marine Plywood Standard BS1088-1:2003.  Gaboon’s air dried density is around 430-480kg per cubic metre as opposed to hoop pine which is around 530-560kg per cubic metre.

see http://en.wikipedia.org/wiki/Aucoumea_klaineana for further information on the species.

The best gaboon marine ply panels used to be manufactured in the Netherlands, Israel and France but with the way that most things in manufacturing have gone much, if not all of the supply available in Australia comes from mills in China, Malaysia or other South East Asian countries.  The price the importers pay for this ply might be great from these places but the quality really lets the end user down.

Marine Ply Manufacturing Standards

Marine Plywood is manufactured to an exacting standard to ensure it is fit for purpose.  The ocean is not a forgiving place and sub standard materials are quickly shown to be inadequate for the task. 

There are two main marine ply standards that we see in Australia namely AS/NZS 2272:2006 (The Australian and New Zealand Standard which our home grown Hoop Pine marine ply is made to) and BS1088-1:2003 (The British standard which is read in conjunction with BS1088-2:2003 which is a standard used for determining glue bond quality in BS1088 marine ply).

Both standards are similar and specify in detail the manufacturing tolerances and allowable defects in ply sheets.

For example;

BS1088-1:2003

AS/NZS 2272

Pin knots in face veneers - up to 6 per square metre
of panel surface


Pin knots in core veneers  - unlimited number
For Face veneers - Knots (sound intergrown)—not
exceeding 4 mm measured across the grain and not
more than four per sheet.

For core veneers - sound knots - unlimited in number



BS1088 as a standard is really quite abused by manufacturers and re-sellers/importers alike.  I have seen so many sheets of so called "BS1088 plywood" which have not been manufactured anywhere near the requirements that the standard specifies.  

Some defects commonly seen on cheap ply in Australia are as follows;

Problem

Face veneers are not compliant and are so thin that even a very light sanding will cut through into the glue line beneath.

BS1088-1:2003 requires

For panels with a nominal thickness of greater than 3.8 mm, each outer ply shall be not less than 1.0 mm thick after sanding and each inner and core ply shall be not more than 4.8 mm thick.

Problem

Glue bleed through into the outer plies rendering it useless for clear finishing.

BS1088-1:2003 requires

Glue penetration shall only be permitted in areas adjacent to permitted defects, up to a maximum of 5% of the area of each outer ply

I have seen sheets of 4 and 6mm ply that have glue bleed through all over the sheet.  One supplier asked me upon enquiry if we were going to be clear finishing because he had bleed through on all their sheets and they would not be suitable.


Problem

Sheet marking.  We have seen many sheets of so called BS1088 marine ply that have a small smudged or illegible stamp on the ply that makes a claim that it is BS1088 compliant. 

BS1088-1:2003 requires

Panels conforming to this standard shall be indelibly marked on the edge or back with the following information in the order shown:

a) the number and date of this British Standard, i.e. BS 1088-1:2003,1)
 and the word “MARINE”;
b) the word “UNBALANCED” if panels are of unbalanced construction;
c) the word “TREATED” if there has been any application of preservative treatment;
d) the nominal panel thickness;
e) the manufacturer’s name or identification mark;
f) the country of manufacture;
g) the panel type, i.e. Standard (S) or Lightweight (LW);
h) the name of the timber species according to BS EN 350-2:1994.

So what we should be seeing on the sheets of standard compliant BS1088 ply is something like;

BS 1088-1:2003, MARINE/UNBALANCED/TREATED/4mm/MD/GB/LW/GABOON

With the "MD" being an example of manufacturers mark, GB being the country of manufacture ( in this case Great Britain) LW showing that the panel type is Lightweight (which is indicitave of ADD of species used) and obviously Gaboon is the species.  There are some small variations on this but we source ply from both the UK and France and this is what is marked on the sheet as required by the standard.

If you are looking at ply that has not been marked as such, what other part of the standard has not been complied with?


Certification

If you read the British standard it states that

“the accuracy of the claim (of standard compliance) is solely the claimant’s responsibility. Such a declaration is not to be confused with third-party certification of conformity.

So probably the biggest problem we face as boatbuilders is that there is a bunch of ply being manufactured that does not comply and both the manufacturers and sellers of the ply are aware of this fact yet they are still happy to tout their product as being BS1088 compliant.    Third party certification that the ply has actually been manufactured to the standard is considered to be the most stringent test of compliance.  Lloyds Register  are one such body that independently assesses products such as Gaboon marine ply against set standards.


The bad ply experience

Unfortunately before a lot of our clients come to us they have already been down the road of being sold "so called BS1088" ply by unscrupulous businesses only to find out that what they have paid for is not compliant to BS1088 at all.

Here's a few stories from our clients;

1.  non gaboon internal cores being stained to look like gaboon and the panel being sold as "gaboon througout" but when cut, the timber inside the ply was almost white in colour.  Vendor wouldn't take it back as the sheet had been cut.....

2. One gentleman purchased a kit for a larger boat only to find out very late in the build that the ply was de-laminating,  Company offerred a better quality (but still non standard compliant ply) to glue on the outside.

3. One client purchased "gaboon" BS1088 ply to find it the internal veneers were different species and hardness and this varied from sheet to sheet which made scarphing a real headache.

4.  One client bought a sample around to our workshop and I was able to get a fingernail under the thin face veneer and pull the face veneer off with a complete failure in the glue line.

5. Another brand new kit I have seen from another supplier had very bad delaminations and voids in the ply veneers.

So to quote an old saying, “oils ain’t oils” or ply aint ply.  Whoever you get your ply from, your supplier should be able to provide you with evidence of compliance to BS1088, generally in the form of third party certification.  As a general rule of thumb, I ask a supplier if they are familiar with and have a copy of BS1088-1:2003.  If they say they don’t, then how can they know if the ply they are selling meets the standard?


So if you are looking for the best quality BS1088 Gaboon ply in Australia please contact us
for further information.

























Denman Marine specialises in custom wooden boat building and repair. We utilise both traditional methods such as carvel or clinker and modern methods such as strip planking, cold molding or clinker plywood.

We can custom build to any design - for example those by Iain Oughtred, David Payne, Paul Gartside, John Welsford, Mark Bowdidge, Francois Vivier, Atkin , Bolger B&B etc.

We are sole Australian agents for Swallow Boats(UK) including the BayRaider, the Australian importer and re-seller of the world renowned Bruynzeel BS1088 Gaboon Marine Plywood (Lloyds certified), Barton Marine products (UK) and Chesapeake Light Craft (USA).

Denman Marine Pty Ltd ATF | ABN: 54779786053 | 2888 Channel Highway Kettering, Tasmania 7155
Mobile: 0413765984 | Tel: 0362674660 | Fax: 0362674991 | Email: andrew@denmanmarine.com.au