Diving the Muizenberg trawler wrecks

The dive site Muizenberg trawler wrecks, I&J trawlers, or Muizenberg wrecks is an offshore recent wreck site in the Muizenberg area of False Bay, near Cape Town in the Western Cape province of South Africa. The water is temperate and the bottom is flat sand.

Understand

Map of the dive site at the Muizenberg trawler wrecks

See also: Diving the Cape Peninsula and False Bay#Understand

This is a dive site which is seldom visited, and is visited mainly as a change from the more popular sites by local divers who have seen most of the other wrecks in the region and feel like a change.

Position

• 1 Western trawler wreck: S34°07.006' E18°31.219'
• 2 Eastern trawler wreck: S34°06.996' E18°31.360'

A third trawler wreck is nearby, but its position as not yet available.

This site is in the Table Mountain National Park Marine Protected Area since 2004. A permit is required.

Name

The name "Muizenberg trawler wrecks" is a simple description of the dive site, which is the wreckage of two steel trawlers off Muizenberg. "I&J trawlers" refers to the trademark (I&J) of the fishing company Irvin & Johnson Ltd, which owned the vessels before they were scuttled. The trawlers are reported to be the Bulby, scuttled in January 1969, and the Iolite, sunk in March 1969, and were sunk as artificial reefs by the False Bay Conservation Society.

Depth

Maximum depth is about 18 m. and the top of the wreckage is about 13 m. Average depth is likely to be about 16 m.

Visibility

The site is relatively shallow and on a fairly fine sand bottom, so any significant swell is likely to stir up the sediment and reduce visibility, which will seldom be very good.

Topography

Sidescan sonar image of the eastern trawler wreck

Sidescan sonar image of the western trawler wreck

Two fairly small steel wrecks, embedded in the sand, both listing to port, with most of the superstructure gone. The third is of similar size, also embedded in sand, but almost upright. Limited access to the hull of the eastern wreck is possible through the deck frames, as the decking is gone. The western wreck is more deeply embedded and very little of the interior is not filled with sand, but there is a small section of deckhouse aft which is open, but hardly worth entering, as one can see all the way into it from outside.

The western wreck is listing at quite a steep angle, and the port topsides are under the sand if they still exist. The starboard side projects out of the sand about 3 m at the bow, and about a metre at the stern. There is a trawling gallows on the starboard side just forward of the stub of the deckhouse. This vessel appears to have been the smaller of the two.

The eastern wreck is more substantial and although also listing to port, the port gunwale is still about a metre above the sand, while the starboard stands up about 3m for much of its length, extending to about 4 m at the bow, which is the shallowest part of the wreck, at about 12 to 13 m, depending on the tide.

Geology: Fine silica sand bottom, almost flat, with wave induced ripples.

Conditions

The site is exposed to southerly swells and south easterly wind waves, so should be dived in westerly winds or a calm, with fairly flat seas. The site is reasonably protected from westerly swells, but it is quite shallow, and will feel the surge if there is a south westerly swell running.

The site is usually at it's best in winter but there are also occasional opportunities in other seasons.

Get in

See also: Diving the Cape Peninsula and False Bay#Boat dives

Access is only by boat — it is much too far to swim. Boats will usually launch at Simon's Town.

The site is about 11.9 km from Simon's Town jetty, or 13.3 km from Miller's Point slipway.

See

Marine life

See also: Diving the Cape Peninsula and False Bay#The marine ecology

The wreckage is well covered by invertebrates, and dominated by the ascidian Redbait, with fairly large numbers of red-chested and mauve sea cucumbers, some patches of strawberry anemones, quite a lot of bryozoan colonies and scattered gorgonian sea fans. There are also black mussels, which may be the alien invasive Mediterranean mussel. The usual selection of starfish and some sea anemones are also present, but not in very large numbers. Fish life is moderate in diversity and quantity, with shoals of small reef fish such as hottentot and strepie, and the usual scattered Roman, redfingers, jutjaw, klipfishes and catsharks. Small groups of pyjama catsharks may be seen sheltering inside the wreckage during the day. This site is in the area where great white sharks are known to cruise, but there are no reports of divers seeing them at the wreck. This is possibly due to a shortage of divers at the site rather than a shortage of sharks.

• 
  Gas flame nudibranch Bonisa nakaza
• 
  Lacy false coral (Bryozoan)
• 
  Colonial ascidians
• 
  Reticulated starfish Henricia ornata
• 
  False plum anemone Pseudactinia flagellifera
• 
  Red bait pods Pyura stolonifera
• 
  Speckled klipfish Clinus venustris
• 
  Pyjama sharks Poroderma africanum

Features

Wreckage of two steel trawlers. They are the only reason anyone would dive at this site. The western trawler is 55 m long, and the starboard topside plating extends on average about 2 m above the sand, sloping downwards from a high point of about 3m at the bow to less than 1m at the stern. The port side of the hull is missing or below the sand. The east wreck is about 50 m long and stands a bit higher out of the sand. There is a rumour that one of the wrecks is the Bulby, reputedly the vessel that collided with the SS Cape Matapan in Table Bay.

• 
  Trawling gallows on the western wreck
• 
  The deckhouse of the western wreck

Specifications:

The Bulby was a single screw steel steam trawler with raised forecastle and quarter deck built at Beverly by Cook, Welton and Gemmell in 1945/6 with yard number 756, for the Boston Deep Sea Fishing Company to Lloyds +100 A1 class with registered dimensions:

• Length (LWL) = 136.15 ft
• Breadth = 25.25 ft
• Depth = 13.25 ft
• Gross tonnage = 360.67
• Register tonnage = 139.29

Hull plating riveted, with seams and butts welded forward of midships. Engine: triple expansion steam engine of 600 indicated Hp built by Charled D. Holmes & Co. Hull.

Photography

This site is unlikely to have very good visibility, but if it is good then there may be possibilities for some good wide-angle shots of the wreckage, otherwise it is mainly good for macro work.

Suggested routes

The skipper will probably drop the shot near the middle of one of the wrecks. Swim along the wreck from end to end, and particularly over the deck, where there are plenty of holes for critters to shelter. The wrecks are small and can be comprehensively visited on one dive. It should be possible to swim from one wreck to the other, but this would require fairly accurate navigation as they are about 200 m apart.

Stay safe

See also: Diving the Cape Peninsula and False Bay#Stay safe

Hazards

The wreck themselves are not very hazardous, though there are some sharp edges and snags. The possible presence of great white sharks may make some divers nervous, but the actual risk is probably quite low. This is up to the diver to decide.

Skills

No special skills required. The depth is within the range considered acceptable for entry level divers.

Equipment

See also: Diving the Cape Peninsula and False Bay#Equipment

No special equipment required.

Nearby

• 1 Dale Brook
• 2 Kalk Bay Harbour Wall
• 3 Fish Hoek Reef

Back to the list of Alphabetical list of sites, or dive sites in the Muizenberg to Kalk Bay area

Other regional dive sites:

• Dive sites of Table Bay and approaches,
• Dive sites of the Cape Peninsula west coast
• Dive sites of False Bay offshore and approaches
• Dive sites of False Bay east coast
• Fresh water dive sites of the Cape Town Metropolitan Area