I frequently get the question why the submarine yacht we built does not have "yacht finish" - the answer becomes clear when watching the picture above.
Yacht finish on a submarine does not last - so how much budget should you dedicate to it...
A submarine yacht when a few months in the water will be covered by marine life. So having a "ferrari finish" on it is only good for selling the yacht in a boat show - in real life the finish on a yacht is only of value if it stays above the waterline...
The owner of a submarine yacht can take two approaches in this matter.
1) a extensive drydock shedule - similar to ships - which include expensive drydocking every few months to keep the antifouling paint fresh . 2) a strategy of "friendly neglect" just accept marine life as part of living on the ocean - stay in the cruising speed range of whales where the drag of marine life on the hull does not make so much difference.
This foto shows the 20 ton prototype on the anchorplace in real world conditions with all ballast in place, rest flotation only 200 kg - watch how much of the hull is actually above the waterline. It is even much less than the military submarine shown above. Exposing as little of the hull as possible above the surface is a strategy to reduce the movements introduced by waves and their intermitent air/liquid contacts that create forces on the hull and introduce sea sickening movements. Exposing only the sail and the hatch ensures "leave coffee cup on the table" living conditions even in stormy weather and in "snorkel mode".
The 20 ton prototype had a nice finish in the beginning but as we ballasted it down to its working floating line - the finished disappeared for ever under the watersurface and was invaded by barnacles.
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For this reason we opted for "putting much less budget" in polishing a useless finish in the next project.
Light conditions in a concrete submarine hull 18x4,6m - 200ton displacement.
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Due to the uplooking viewports of 50cm diameter which recieve much more light than the small windows of a business jet - the interior designer can work with a "natural lighted space" .
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Inside the 20ton prototype - a simple wood interior - a lot of daylight on the anchorplace. The difference in the quantity of light entering trough the uplooking viewport, and trough the side looking viewports - inspired the "uplooking only" design in the next project. (200 ton Cartagena).
The exclusive ferrari look that we generally asociate with YACHTING is exclusivy applied ABOVE the waterline - the underwater part of the structure is much less polished for good reasons.
The real beauty and luxury impression of a submarine yacht is not in the finish of the (submerged) outside of the hull - it is in the interior design of the inside. So if the hull has a "crude look" while standing in the shipyard on land - this does not mean that visitors that come aboard when the boat is afloat will see anything that looks crude.
Their impression of the boat is something like that:
A concrete dock from the Japan tsunami washed ashore in the United States a year later shows clearly how a concrete structure floating in the ocean without undergoing a maintainance shedule would look like - it becomes obvious why it doesn't make a lot of sense to put a polished ferrai finish at it in the first place.
The best strategy is to "embrace sealife" as part of the deal and enjoy the ecosystem developing on the hull - it will attract fish to the hull in the open sea so that you will have a interesting view when looking out of your viewports - especially at night when the light in the viewports attracts additional plankton to the structure.
A steel hull can not embrace sealife as the barnacles would destroy the painting speed up corrosion - for a concrete hull barnacles do no harm.