Talk the line

Q&A: Getting technical with leading naval architect Perry van Oossanen.

Written by Esther Barney

29 December 2017


Perry van Oossanen heads up the team working on large yacht and ship projects at Van Oossanen naval architects, founded by his father Piet in 1992. Having broken the mould with its multi-award-winning, revolutionary hull designs, the Dutch firm recently revealed a new 55-metre motor yacht concept with Rossinavi, Zephyr. He sat down with Ocean for a quick-fire round on how the world of naval architecture is moving and shaking things up…

Ocean Magazine (OM): Van Oossanen’s proprietary Fast Displacement Hull form (FDHF) has had a lot of attention in recent years, notably with your work on Heesen projects and now a 55-metre concept with Rossinavi. What makes it so successful and unique?
Perry van Oossanen (PO): We first applied the FDHF design on the 65-metre Heesen motor yacht Galactica Star, which was delivered in 2013, although our design work on the project took place back in 2009. It is the only hullform for displacement yachts of this size that is able to perform efficiently at a range of speeds. Conventional hard-chine, semi-displacement yachts are able to travel fast, but they are not efficient at slower speeds, and full displacement yachts can only travel at slower speeds, albeit efficiently. We were able to marry the two types of hullform into one.

Today, shipyards and owners are increasingly aware of the impact that a yacht can have on the environment. Although a yacht can never be “completely green”, you can try to minimise the overall impact, which is what we are finding our clients want.


OM: Why did it take until 2009 for such a hullform to be discovered, and then patented?
PO: When I was at university, we were taught that if you want to build a fast yacht you use a hard chine hull, and a long-range yacht that is efficient at slower speeds uses a displacement hull form. Nobody really looked into what was between these two ends of the spectrum. Back in the “old days” – by which I mean 15 years ago – it took a huge amount of investment in time and money to carry out modelling and testing, so it was harder to justify trying things just to see. But as advances in computer analysis allowed us to look into this much faster and more economically, we were given a new freedom to explore the fringes of traditional naval architecture.

OM: Are naval architects able to satisfy the demands from your clients for yachts that meet wide-ranging criteria like higher speeds and longer ranges?
PO: In actual fact, we find that most clients are not very particular about what they want from these technical sides of a project. They may have a clearer picture of what they envisage for layouts of the rooms, materials and finishes to be used, and so on. But we have fewer demands from clients on the naval architecture side of things, partly due to how inaccessible it can be for them to understand what is technically possible. That being said, there are some experienced owners who know what they want – or more often what they don’t want – from a new project. These can be more specific in terms of technical demands. But in reality, we find that we are pushing new innovations and ideas out to the market rather than having new challenges asked of us.

OM: Do you have any predictions for the future of naval architecture on multihulls in the luxury yacht market?
PO: We do have some involvement with multihulls and have consulted on a number of projects, including one for a 70-foot [21 –metre] power catamaran at the moment. They are very popular in Asia and Australia, where there is a lot of space; but we find that they are less numerous in Europe as the marinas are crowded, it’s more expensive to pay for dockage, and a lot of multihulls therefore end up staying at anchor.

One thing that we have noticed on a number of motor yacht multihulls is that they have not always made the best use of exterior space. We are working on a new design for a 60-metre trimaran with Australian designer Sam Sorgiovanni, who has recently worked with Echo Yachts on a number of multihulls. Under 500gt, the yacht has lots of exterior space and should be very exciting. Stay tuned for more information soon!


OM: Do yacht owners underestimate the impact that naval architecture can have on the efficiency and environmental impact that a yacht can have?
PO: Absolutely, yes. A great example is a recent Dutch trawler patrol boat project we did where we were able to reduce the installed power and carbon dioxide emissions by almost 50 percent, just through smart naval architecture. It helps across the board, with reduced engine size, lower emissions, lower running costs and so on. This was an extreme example, but realistically we could probably improve efficiency by between 20 and 30 percent on most yacht designs through similar methods.

We find that shipyards tend to want to limit changes that they perceive as a potential risk – an unknown – on a project. The drive is coming from owners for yachts that are more “green” (or what they can label as “green”).

OM: Is this green drive helping to improve feedback between naval architecture and propulsion systems?
PO: We are finding that shipyards and owners are now more open to considering different options of propulsion system. It has been a growing trend and that I think will mature in the next five years. Whether hybrid, diesel electric or conventional diesel propulsion, considering the choice of system is part of the discussion where it was not before.

Finding the most efficient option really depends on how the yacht will be used, and there are many different factors to assess what will make the final vessel seaworthy and stable. Will the yacht be moving a lot? Will it spend a lot of time in port, or at anchor? We have to balance up all the different points, and sometimes a conventional diesel propulsion system does turn out to be the best choice; it is not always that hybrid or diesel electric will mean greater efficiency.


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