Choosing the best wood for marine construction is not a style decision. It is an engineering one. A jetty, fender pile or lock gate sits in water for decades, takes impact from ships and suffers attack from fungi, insects and, in salt water, marine borers. Pick the wrong timber and you will be replacing it in a few years. Pick the right one and it may outlast the steel around it.
In this guide we compare the hardwoods most used in marine and hydraulic works, explain what makes a timber suitable, and help you match species to the job. We supply several of these from Central Africa at Global Timber Trade Hub.
In short
- Marine timber must be dense, strong and naturally very durable.
- Azobe (Ekki) is the reference heavy timber for European waterworks.
- Okan and Mukulungu are strong alternatives when Azobe supply is tight.
- Bilinga resists marine borers well and suits decks and jetties.
- Tali is economical for piles, sleepers and boardwalks.
- Always check grading, dimensions and legal documents before ordering.
What makes a good marine timber?
Not every hard wood is a good marine wood. Engineers usually look at five properties together:
- Natural durability: resistance to fungal decay in wet conditions, rated from class 1 (very durable) to 5 (not durable) under EN 350.
- Resistance to marine borers: shipworms and gribble attack timber in salt and brackish water.
- Density and strength: high bending and compression strength for loads and impacts.
- Abrasion resistance: fenders and rubbing strips take constant wear.
- Availability in large sections: piles and beams need long, wide, sound timber.
The best wood for marine construction scores well on all five, without chemical treatment.
1. Azobe (Ekki, Bongossi)
Azobe (Lophira alata) is the most widely used heavy marine hardwood in Europe. The Netherlands and Germany have used it for canal banks, lock gates, bridge decks and fender systems for generations.
- Density: about 1,000–1,100 kg/m³ (it sinks in water).
- Janka hardness: about 3,350 lbf.
- Durability: durable to very durable in fresh water.
- Best for: fender piles, quay walls, lock gates, bridge decks, crane mats.
One honest note: in tropical salt water with heavy shipworm pressure, Azobe is less resistant than some other species. In temperate waters it has an excellent record.
2. Okan (Denya)
Okan (Cylicodiscus gabunensis) is increasingly specified as an Azobe alternative. It is very hard, class 1 durable and available in large sections.
- Density: about 880–950 kg/m³.
- Best for: bridges, hydraulic works, heavy decking, sleepers.
Okan dries slowly and can check in thick sizes, so it is usually supplied air dried for structural use.
3. Bilinga (Opepe)
Bilinga (Nauclea diderrichii) is lighter than Azobe but very durable and has a good record against marine borers. Its golden colour makes it popular where the timber is visible.
- Density: about 720–780 kg/m³.
- Best for: jetties, piling, lock gates, decking, boardwalks.
4. Tali (Missanda)
Tali (Erythrophleum species) is a dense, very durable timber used for railway sleepers, piles and heavy boardwalks. It is often one of the most economical heavy timbers per cubic metre.
- Density: about 900–930 kg/m³.
- Best for: piles, sleepers, boardwalks, bridge components.
5. Mukulungu
Mukulungu (Autranella congolensis) is very heavy and class 1 durable, with a fine texture and reddish colour. It suits marine and heavy flooring uses where appearance also matters.
- Density: about 900–1,000 kg/m³.
- Best for: jetties, fenders, heavy-duty decking and floors.
6. Greenheart
Greenheart (Chlorocardium rodiei) from Guyana is a classic marine timber with an excellent reputation against marine borers. Supply is limited to one region, which makes it harder to source and often more expensive. We compare it in detail in our Azobe vs Greenheart guide.
7. Doussie (Afzelia)
Doussie is very durable and extremely stable. It is not a pile timber, but it is excellent for marine joinery, boat parts and exposed decks where movement must be minimal. African Afzelia is CITES Appendix II listed, so it ships with a CITES permit.
8. Iroko
Iroko is lighter and easier to work. It is a good choice for marine joinery, boat building, deck boards and above-water parts of structures, rather than for heavy piles.
Marine timber comparison table
| Species | Density (kg/m³) | Durability | Typical marine use | From (USD/m³) |
|---|---|---|---|---|
| Azobe | 1,000–1,100 | Durable to very durable | Fenders, lock gates, quays | $650 |
| Okan | 880–950 | Very durable | Bridges, hydraulic works | $650 |
| Tali | 900–930 | Very durable | Piles, boardwalks | $650 |
| Bilinga | 720–780 | Very durable | Jetties, decks | $700 |
| Mukulungu | 900–1,000 | Very durable | Fenders, heavy decks | $700 |
| Iroko | 640–690 | Very durable | Marine joinery, decks | $950 |
| Doussie | 730–830 | Very durable | Exposed joinery, decks | $1,350 |
Prices are indicative starting prices per m³, FOB Central Africa.
Matching species to the job
Fender piles and rubbing strips
Choose the hardest, densest timbers: Azobe, Mukulungu or Okan. They absorb impacts and resist abrasion from hulls.
Jetties and pontoons
Bilinga, Tali and Azobe for structure; Iroko or Bilinga for deck boards where people walk.
Lock gates and sluices
Azobe and Greenheart are traditional. Okan and Bilinga are proven alternatives. Stability and large clear sections matter here.
Boardwalks and footbridges
Tali, Bilinga and Okan give long life at a sensible cost. See our guide to the best hardwood for decking.
Boat building
Iroko, Afrormosia, Sapele and Okoume plywood are the usual choices. Read our guide to Okoume marine plywood.
Sizes and product forms for marine projects
For marine and civil works we typically supply:
- beams and baulks from 100×100 mm up to 300×300 mm, in lengths up to about 12 m;
- planks and decking from 25–50 mm thick;
- railway sleepers and crane mats, standard or custom;
- round piles where export of logs is legally permitted.
Large heavy sections are normally supplied fresh sawn or air dried, because kiln drying very dense timbers in big sizes causes cracking.
Installation tips
- Pre-drill all fixings in dense timbers like Azobe and Okan.
- Use stainless or hot-dip galvanised fixings.
- Seal end grain after cutting to reduce splitting.
- Allow for some movement and checking in large sections; it is normal and rarely structural.
Legality and documents
Public works contracts usually require proof of legal origin, and many specify certified timber. Every shipment we send includes legality and chain-of-custody documents, a certificate of origin and a phytosanitary certificate. FSC or PEFC volumes can be quoted on request, subject to availability. More on our sustainability page.
Common mistakes
- Using decking species for piles: lighter woods are not designed for impact and ground contact at depth.
- Kiln drying heavy sections: it often causes more cracking than it prevents.
- Ignoring borer risk: in tropical salt water, ask for species with a proven borer record.
- Specifying one species only: allowing two equivalent species often shortens lead times.
Fresh water vs salt water
The water your structure sits in changes the choice of timber. In fresh water, the main threat is fungal decay in the zone that is wet and dry in turn. Most dense African hardwoods handle this very well. In salt and brackish water, marine borers such as shipworm and gribble add a second threat. Their pressure is highest in warm tropical seas. For those sites, choose species with a proven borer record, such as Greenheart or Bilinga, and discuss protection with your engineer. Our guide to Azobe vs Greenheart goes into this in more detail.
Design life and maintenance
A well-chosen hardwood marine structure can last 25 to 50 years. Three things decide where in that range you land. First, the species and its durability class. Second, the design: timber that drains and dries between tides lasts longer than timber that traps water. Third, inspection: a simple yearly check of fixings, wear and any borer damage lets you replace single members before small problems grow. Plan for some replacement of fender piles and rubbing strips, which take the hardest wear.
Fixings for marine timber
Dense hardwoods are strong, but their fixings often fail first. Use hot-dip galvanised or stainless steel bolts, washers and nuts, sized for the load. Pre-drill every hole. Many tropical hardwoods contain natural acids that attack plain steel, so avoid untreated fixings. Where timber meets concrete or steel, add a gap or a pad so water does not sit in the joint.
How to specify marine timber in a tender
A clear specification avoids arguments later. State the species or a list of accepted species, the strength class, the grading standard, section sizes and tolerances, maximum allowed defects, moisture condition, and the legality documents required. If you allow alternatives, say so: it often makes the project cheaper and easier to supply. We are happy to review a draft specification before the tender goes out.
Ordering a mixed marine container
Many marine projects need more than one species. A common mix is Azobe or Okan for piles and beams, Tali for walers and sleepers, and Bilinga or Iroko for decking and handrails. We can load several species and sections in one container, each bundle clearly labelled and listed separately on the packing list. This keeps freight costs down and simplifies your paperwork, because one set of documents covers the whole shipment.
Sources
- CIRAD Tropix for durability and mechanical data on tropical species.
- Lophira alata on Wikipedia for background on Azobe.
Related guides
- Azobe vs Greenheart
- Best hardwood for decking
- Iroko vs teak
- Heavy construction and marine timber
- How to import timber from Africa
Frequently asked questions about marine construction timber
What is the best wood for marine construction?
For heavy structures, Azobe is the reference in Europe, with Okan, Mukulungu, Bilinga and Tali as proven alternatives. For marine joinery, Iroko and Doussie are excellent.
Does marine timber need chemical treatment?
Very durable species such as Azobe, Okan and Bilinga are normally used untreated.
How long does Azobe last in water?
Well-designed Azobe structures commonly give 25 years or more in fresh water and temperate marine settings.
Can you supply large beams?
Yes. We supply beams up to about 300×300 mm and lengths up to about 12 m, subject to the species and available logs.
Get a quote for marine timber
Send your bill of quantities, section sizes and lengths through our quote form. We will recommend the right species and reply with price per m³ and lead time.