In India, the fishing industry alone incurs an annual loss of over 120 million rupees on account of biodeterioration of wooden fishing craft. None of the timber species, currently in demand for boat-building, possesses an natural bioresistance and will be completely destroyed within 6 to 12 months. Preventive measures against biodeterioration range from application of several indigenous formulations to metallic sheathings and pressure impregnation of wood with preservative chemicals. These methods do not provide lasting protection, as each has its own short-comings and inadequacies. The need for long-term research in the field of marine biodeterioration for improving the efficiency of currently known control measures, with emphasis on application of non-polluting biological methods, is stressed

Santhakumaran, L.N.

Aquatic Commons

Journal of the Indian Fisheries Association 
189 1988, 275-282 
BIOOETERIORATION OF WOODEN BOATS - A MAJOR 
PROBLEM FACING MARIN[ FISHERIES 
L.N. SANTHAKUMARAN* 
Institute of Wood Science and Technology, Bangalore 560 003. 
ABSTRACT 
In India, the fishing industry alone incurs an annual 
loss of over 120 million rupees on account of biodeteriuration 
of wooden fishing craft. None of the timber species, currently 
in demand for boat-building, possesses any natural bio-
resistance and will be completely destroyed within 6 to 
12 months. Preventive measures against biodeterioration 
range from application of several indigenous formulations 
to metallic sheathings and pressure impregnation of wood 
with preservative chemicals. These methods do not provide 
lnsting protection, as ei:!Ch 
inadequacies. The need for 
of marine biodeterioration 
of currently known control 
application of non-polluting 
been stressed in the paper. 
has its own short-comings and 
long-term research in the field 
for improving the efficiency 
measures, with emphasis on 
biological methods, has also 
INTRODUCTION 
Despite extensive mechanisation and introduction of modern 
fishing me thuds, the backbone of marine fisheries in India is 
still the traditional fishermen with their indigenous craft. The 
development of fisheries is, therefore, intimately linked with 
their "ocio-economic upliftment. Supply of suitable materials 
for the construction of their craft and its maintenance are vital 
for the sustained activities of these poor ffsher-folk. 
for 
The traditional construction 
marine constructions in India 
material 
1s timber. 
* Present Address : Wood Preservation Centre (Marine), 
used extensively 
Timber is prone 
C/o National Institute of Oceanography,Dona Paula,Goa 403004. 
27o 
Fig. 1 
Fig. 2 
SANTHAKUMARAN 
A country boat at Terracol (Goa) showing heavy 
borer damage. 
Keel and bottom planks of an Arab dhow (of teak) 
heavily demaged by marine borrers in 18 months 
in Mandovi eituary (Goa). 
Fig. 3 
Fig., 4 
BIODETERIORATION OF WOODEN BOATS 277 
Casuarina poles from Killai Fish-farm (Chidambaram 
Tamil Nadu) split open to show damage by shipworm~ 
with in 6 months. 
A piece oi copper sheet from 
of a mechanised boat in Bombay 
by barnacles. 
'the wooden hull 
showing fouling 
278 SANTHAKUMARAN 
to rapid destruction by marine organisms like shipworms ( Teredi-
nidae), p iddocks ( Pholadidae), pill-bugs (Sphaeromatidae) and g rib-
bles (Limnoriidae). The wood surf ac~e as well as that of other 
construction materials, such as steel, fibre-glass or ferrocement, 
are also subject to heavy fouling by sedentary organisms like 
coelenterates, bryozoans, sponges, serpulids, barnacles, bivalves 
and by marine algae. So far, about 54 species of wood-borers 
and over 170 species of major foulers have been reported from 
Indian coasts (Nair, 1984; Santhakumaran et al., 1 9 8 5; San t h a-
kumaran and Srinivasan, 1987). While the borers tunnel through 
the timber and destroy it with remarkable rapidity (Figs. 1 to 3), 
the main foulers (Fig. 4) roughen the hulls, thereby increasing 
the drag resulting in loss of speed and high rate of fuel con-
sumption. In a steel hull, the foulers promote corrosion as well. 
Thus, marine biodeterioration is really an impediment to the 
development of fisheries. 
ECONOMIC IMPORTANCE 
The financial implication of the problem caused to the 
fishing industry by marine foulers and wood-borers is of a colossal 
magnitude and the remedial measures so far evolved to combat 
biodeterioration are quite inadequate and still expensive. The 
annual loss to the fishing industry, based on a survey conducted 
in 1981, is over 120 million rupees (Santhakumaran and Srinivasan, 
1987). This expenditure is only for repairing and restoring remedial 
measures against biodeterioration and does not include the actual 
cost of the timber used for construction or for annual replace-
ments and also the destruction caused to large quantities of 
timber used to provide the necessary infrastructural facilities at 
about 1,300 mam fish-landing centres and also for mariculture 
at several places. For example, in India, investment worth 600 
million rupees is involved in the indigenous fishing boats itself 
(Ravindran et al., 1984). If all these are taken into consideration, 
together with the hike in the cost of ingredients used for preparing 
protective coatings and also in labour charges since 1981, the 
additional expenditure at present will soar to .a staggering figure. 
Despite this enormous expense on hull maintenance, wooden 
boats suffer extensive borer damage and heavy fouling (Figs. 
1, 2 and 4). 
The problem is again aggravated as none of the timber 
species currently in demand for boat-building (like Tectona grandis, 
Terminalia alata, Terminalia paniculata, Lagerstroemia microcarpa, 
Xylia :rylocarpa, Mangifera indica, Artocarpus hirsutus, Hopea 
parviflora, Calophyllum inophyllum, Bomba:r ceiba, Albizia spp , 
BIODETERIORATION OF WOODEN BOATS 279 
Melia composita, Pterocarpus dalbergioides and Pterocarpus 
marsupium) possesses any natural bioresistance against borers 
and foulers. Even teak is destroyed completely within a short 
time (Fig. 2). Further, considerable inconsistencies in durability 
of the same timber species at different localities have also 
been reported. Here is a problem that has defied a -permanent 
solution' but at the s'ame time di vising a preventive method 
is indispensible for the economic effectiveness of the 
fishing industry. 
CONTROL OF BIODETERIORATION 
Indigenous methods : Several indigenous preservative for-
mulations are employed by Indian fishermen for protecting the 
hulls of fishing craft from biodeterioration. Some of the in-
gredients used, either alone or in combination are : crude fish 
oil, cashewnut shell oil, po~n (Calophyllum sp). seed oil (also called 
hunnai oif or undi oil), r:1eem (Azadirachta sp) seed oil,crude engine 
oil~ groundnut oil, castor oil, coal tar, karanjel oil (from seeds of 
Pongamia pinnata), 'chandrus' or 'dammer batu' (solidified resin 
from trees of the famHy Dipterocarpaceae). and lime (for details 
on commonly used combinations, see Santhakumaran and Jain, 
1983 ). Coatings of these indigenous preservatives have no 
particular efficacy for the purpose they are used, due mainly 
to their poor adherence to the timber ·surface. Their apparent 
effectiveness is evidently due to the frequency ·of application 
(sometimes 3 to 4 times in a year) and its continued use is 
only a practice governed by tradition. 
Mechanical barrier methods :Protective methods by providing 
a mechanical barrier include met<:~ll (iron, steel, zinc, copper 
and alioy of copper and zinc or aluminium and magnesium) or 
fibre-glass sheathing and application of special marine paints 
containing toxic chemicals (salts of copper, and mercury, tri-
butyl-tin oxide, tri-butyl-tin fluoride or tri-butyl-tin acetate 
etc.). Methods are effective· against marine borers as long as 
the sheathing remains in good condition. One of the serious 
problems encountered is the rapid corrosion of metals and their 
alloys and peeling of the coatings due to mechanical damage. 
Copper sheathing, though very effective, is prohibitively costly. 
Further, these mechanical barriers do not prevent the growth 
of fouling organisms (Fig. 4). Nevertheless, the method is useful 
in protecting fixed timber structures like fishing stakes, poles~ 
jetty piles, etc., from borer damage. In the case of marine paints, 
excessive initial leaching of the toxicant from the film and 
also mechanical damage contribute to early failure of even 
highly acclaimed antifouling paints.. New development in this 
field is the antifouling elastomers which can be applied in thick 
200 SANTHAKUMARAN 
coatings, thereby holding larger quanti ties of the toxic 
components. 
Chemical impregnation methods: Pressure-impregnation of 
timber with standard wood-preservatives affords worthwhile 
protection. Pressure-treated test panels of several species of 
Indian timber remained free of biodeterioration even after 7 
to 15 years; while their life in the untreated condition is only 
6 to 12 months (Santhakumaran et al., 1984). It is the best method 
for fixed structures. Creosote, creosote-fuel oil mixture (50:50), 
copper-chrome-arsenic (CCA) and copper-chrome-boric (CCB) 
are some of the good preservatives. Recommended dosages 
are about 320 kg per cubic metre of oil type and 32 kg per 
cubic metre of water-borne preservatives. It is impor~ant that 
all cutting and boring of_ timber should be completed before 
it is impregnated. If any untreated wood is exposed during the 
construction of the boat with impregnated timber, such exposed 
surfaces should be liberally coated with the preservative." Two 
catamarans made out of Albizia chinensis and treated with CCA 
(at the dosage of 16 kg and 32 kg per cubic metre) remained 
free of borer attack and fungal decay even after 14 years of 
continuous operation at Visakhapatnam, whereas in the untreated 
condition their life is only about 5 to 7 years - that too with 
frequent maintenance by way of replacements of damaged portion 
and "shortening" (S.anthakumaran and Srinivasan, 1987). These 
catamarans are still in service • 
Although long-term protection is imparted to marine timber 
by pressure-impregnation method, it has not become popular 
in India, mainly due to lack of treatment facilities along the 
coasts. The method can undoubtedly enhance the service life 
of boats and also can contribute to the rational utilization of 
secondary varieties of timber, leading to the conservation of 
our forest wealth. It may, however, be mentioned here that,. 
as in the case of natural bioresistance, durability of pressure-
treated timber also may vary at different localities, as a con-
sequence of differential fixing of chemicals in the timber, con-
ditions at the area deciding the leaching rate and also the 
composition of the borer fauna. Strength properties of the treated 
timber also are to be evaluated in more details. 
FUTURE TRENDS IN RESEARCH ON 
MARINE BIODETERIORATION 
Further long-term investigations on marine · biodeterioration 
are certainly needed to improve the efficacy of control measures 
BIOOETERIORATION OF WOODEN BOATS 281 
curently available. The use of toxic chemicals may in due course 
of time aggrevate the hazard of pollution. Hence, the future 
emphasis on research in. this field should be on the biology of 
the wood-infesting organisms, so as to find out the weak-links in 
their life history, and also on the biochemical action of naturally 
occurring chemicals present in certain timbers on wood-borers 
(like interference of calcium metabolism of borer larvae by 
obtusaquinone present in Dalbergia retusa). Similarly the experi-
mental evidence for the attraction of larvae of fouling organisms, 
th-rough the production of certain proteins (lectins), to specific 
bacterial polysaccharides on the substratum, provides a new 
technique in combating foulers. By preventing bacterial biofilm 
on the surface, it may be possible to block settlement and growth 
of marine organisms. These new trends in research may result 
in developing non-polluting biological control measures. Marine 
biodeterioration is indeed a major bottleneck in the development 
of fisheries and any improvement in the efficacy of existing 
antifouling and antiboring techniques, indigenous or modern, 
would be a very significant contribution curtailing considerable 
expenditure on maintenance of books, much to the relief 
of the poor fishermen of India. 
ACKNOWLEDGEMENTS 
The author takes great pleasure to contribute this article 
for the special volume being brought out to felicitate and honour 
six leading fisheries personalities of India. 
REFERENCES 
Nair, N.B. 1984. The problem of marine timber destroying 
organisms along the Indian coasts. Proc. Indian Acad. Sci. 
(Anim. Sci.), 93(3) : 203-223. 
Ravindran K., A.G.K. P illai and N. ,Unnikrishnan Nair, 1984. 
Improved chemical preservative treatment for traditional 
craft. Fish. Tech. News-Letter, 3(2), Jan.-March, 1984c 
Santhakumaran, L .N. and J.C. Jain, 1983. Deterioration of 
fishing craft in India by marine wood-borers. J. Indian Acad. 
Wood Sci., 14(1) ~ 35-52. 
282 SANTHAKUMARAN 
Santhakumaran, L.N., J.C. Jain and M.C. Tewari, 1984. Per-
for_mance of preservative-treated timber against bio-
deterioration in Indian waters. The Internat. Res. Group on 
Wood Presery. (Stockholm). Document No. IRG/ WP I 41 06:1-30. 
Santhakumaran L.N., and V. V. Srinivasan, 1987. Marine biD-
deterioration - an impediment to the development of fisheries. 
First Indian Fisheries Forum , 4-8 Dec., 1987, Mangalore. 
(Proceedings in Press). 
Santhakumaran, L.N., S. Udaya Bhaskar and V. V. Srinivasan, 
1985. Occurrence and distribution of marine wood-borers 
of India. J. Indian Acad. Wood Sci., 16( 1) : 40-60. 


Biodeterioration of wooden boats: a major problem facing marine fisheries

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Biodeterioration of wooden boats: a major problem facing marine fisheries

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