The dive site Finlay's Deep or Mont Blanc is an offshore rocky reef in the Castle Rocks restricted area on the False Bay coast of the Cape Peninsula, near Cape Town in the Western Cape province of South Africa.

Understand

Map of the dive site at Mont Blanc Reef, also known as Finlay's Deep

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

This is a small reef with a large number of Gorgonian sea fans.

Position

• S34°15.005' E018°29.194' 1 Finlay's Deep: About 900 m directly offshore of Finlay's point

This site is in a Marine Protected Area (2009). A permit is required. The site is entirely inside the Castle Rocks Restricted Zone.

Name

The name "Finlay's Deep" is a reference to Finlay's Point inshore, and that the reef is relatively deep. The alternative name is “Mont Blanc” as the top of the main granite boulder appears white as if snow-covered.

Depth

Maximum depth is about 30 or 31 m and the top of the reef is reported to be about 20 m.

Topography

The reef is a narrow outcrop of granite about 37 m long from north east to south west on an axis of 39°magnetic, and about 7 m wide. The reef is notched by a number of fairly deep cracks, but mostly they are not very wide, The highest point is only a few metres shallower than the sand bottom which is at 30 m. Some sections of the reef are quite low, in the order of 1 m at the north end. There appears to be another outcrop slightly further offshore, probably about 5 to 10 m to the east, of unknown extent.

Geology: Late Pre-Cambrian granite of the Peninsula pluton.

Conditions

The site is exposed to swell from the south east, and to a certain extent, from the south west. Longer period swell will make conditions on the reef uncomfortable due to strong surge, but short period waves will just make it uncomfortable on the boat. Visibility is less predictable, and at this time is largely a matter of luck and reports from divers who were in the area recently.

The site is usually at it's best in winter but there are also occasional opportunities at other times of the year, though least often in summer, when the south east wind tends to blow much of the time.

Get in

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

Access to this site is only by boat. The site is approximately 3.2 km from Miller's Point slipway and 10.5km from Simon's Town jetty.

See

Marine life

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

The most obvious group is gorgonian sea fans. There are large numbers of Palmate, Sinuous, Flagellar and Multicolour sea fans present but not very big. The surface of the rock is encrusted with Mauve sea cucumbers, Strawberry anemones and sponges, with a scattering of Elegant feather stars and Striped anemones.

• 
  Colonial ascidian
• 
  Green moon sponge
• 
  Multicolour sea fan
• 
  Reef life at Finlay's Deep
• 
  Sea fan
• 
  Sea fan with basket star

Photography

The site is usually dark due to the depth, so anything other than macro will require an external flash.

Routes

No particular route recommended. The reef is small enough to explore on a single dive. If you have time left you might explore to the east of the southern end in case there is more reef in that area.

Stay safe

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

Hazards

The site is quite far offshore, and the area is often dived in an offshore wind, so there may be a risk of getting lost on the surface if the wind comes up strongly.

Skills

Certification appropriate to the depth will be expected, but no special skills are required. Ability to deploy a DSMB may be useful.

Equipment

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

No special equipment is required, but a DSMB will be useful if you have to surface away from the shotline.

Nearby

• 1 Graeme's Spot and The Jambles
• 2 Finlay’s Point
• 3 Finlay's Pinnacle
• 4 Carnaby Street Pinnacle
• 5 Atlantis Reef
• 6 Sherwood Forest
• 7 Partridge Point - Seal Rock
• 8 Partridge Point - Big Rock
• 9 Partridge Point - Peter's Pinnacles

Back to the Alphabetical list of sites, or list of dive sites in the Finlay's Point to Partridge Point 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