I also think you lack some details: for example, I don't see any funnels or exhaust pipes.
that is because this vessel have it's exhaust pumped directly in to the water-jet stream. (believe it or not.
)
many yacht have there exhaust under water. there engine system doesn't demand that much. like an Naval ship with it's 25.000-40.000hp on an 50-60 meter hull!