Week 7 - Fouling

Question 1

What are some examples of bio fouling organisms?

Answer 1

Barnacles Feeding
Tubeworms
Green Algae
Mussels on a boat

Question 2

What are some user operational reasons why fouling is important?

Answer 2

Increases roughness on surface
• Increases fuel consumption/decreases efficiency
• Increases weight
• Damages electronic equipment in the sea (sonar domes
etc.)
• Breaks paint on the surface and causes corrosion

Question 3

What are some environmental concerns of fouling?

Answer 3

Emissions Nox, Sox, Greenhouse gases (GHG)

Pressures to safeguard the marine environment from the harmful effects of chemical biocides, water quality and sediment contamination

Efforts to limit the spread of invasive non-indigenous species (NIS) via ship fouling

Question 4

What are some economic concerns of fouling?

Answer 4

 Global economy
 Cost of fuel?
 The economic need to extend the interval between drydockings
 The expensive maintenance and/or replacement of ship’s rudders
 The cost of cleaning up the contamination and pollution caused by biocidal antifouling paint on ships’ hulls.

Question 5

What are some examples of coatings to be used to prevent biofouling?

Answer 5

Lead and copper sheets (for wooden vessels)
Heavy metals (copper, arsenic, mercury)
TBT conventional coatings
Biocidal coatings

Question 6

What are some disadvantages of TBT coatings?

Answer 6

It persists in water
Shows toxic effects in marine organisms
It may enter the food chain

Question 7

What are the requirements for marine coatings to prevent biofueling?

Answer 7

Anticorrosive
Antifouling
Environmentally acceptable
Economically viable
Long life
Compatible with underlying system
Resistant to abrasion/bio degradation/errosion
Capable of protecting regardless of operational profile
Smooth

Question 8

What must be avoided for marine coatings to prevent bio fouling?

Answer 8

Toxicity to the environment
Persistent to the environment
Expensive
Chemically unstable
A target for non-specific species

Question 9

What can be done to maintain propellers?

Answer 9

Propeller polishing

Keeping In a dry dock

Question 10

How is the inner region of the turbulent boundary layer affected by surface conditions?

Answer 10

Viscous sublayer

Log-law region

Question 11

How is the outer region of the turbulent boundary layer affected by surface conditions?

Answer 11

It isn’t