My perspective is a bit diferrent. I used to sail a 4,600kg 35' one-design racer cruiser with wife and two kids. A bit of a workload for singlehand cruising, especially upwind,where we usulaay get a 4'-5' chop. When I added 320kg of water ballast and another 430kg of batteries on top of the keel, I got a lot better behavior upwind, as it slices waves better. Also, on puffs, a more gentle transition to heel where it allows me time to trim as necessary. Let's say the boat is more civilized, and maybe MORE able to stay at hull speed. The only point of sail I have lost a bit of performance is downwind in surf. The other day, we sailed a hard 20-mile upwind leg, 17kts TWS and 25kts puffs, alongside a 2006 Dufour 40. With my previous light displacement, that would not be possible. I don't race, and to get a full crew on board, I'd have to take out the batteries.
Having said that, it's good if you can add payload to balance a boat, but I'm assuming that diferrent hull shapes will assimilate differently to payload, and where it is placed.
Just pointing out that numbers don't tell all, and the D36 did get a very good review from YW, especially regarding its manners and behavior.
Finally, why do all these tests and videos of boats show flat water only?
Paulo, glad you're back online!
Glad you have liked the Dufour 40, the previous model. It was my second choice (as a 5 year old used boat) if I could not get a Comet 41s. It was not by accident that I bought a medium weight relatively narrow boat with a good B/D ratio. It had to do with what you say.
I agree with you and the two Dufour 40, the previous model (the one you sailed and the new model) are a good example of what you say. The new one will be faster under most conditions but on the conditions you have described I think the older one would not only be faster but also more comfortable.
The new one is slightly heavier and has less 350kg of ballast for the same draft. I don't think that the new more efficient keel can give the same effect than the other one, takong into account the weight difference in ballast. The new boat weights 7950Kg and the old one weighted 7800kg on the basic version and 7300 on the performance version (the one that I was looking for).
This gives a B/D for the old Dufour 40p of 37% and the new one has only 29%. Both boat have about the same beam but the new one has less rocker and a flatter hull.
Regarding your comments, there is a sailing situation where the lighter boat has a big advantage and that is in very light winds. Regarding going upwind, weight can only be a significant advantage (not considering comfort that is a relative subject) if that weight is on the ballast, given more righting moment to the boat and allowing it to carry more sail. But has we have seen the weight on the Dufour 36 is not in the ballast but in the hull. If you take a look ar the B/D ratio of the other mentioned boats (with the exception of the First) you are going to see that they are not only lighter but also that they carry proportionally much more ballast.
Look for instance to the J109: It weights less 1500kg than the Dufour and the difference in ballast is only 130kg. Or look at the new J111 that has a difference in weight of 2300kg for a difference in ballast of 330kg. Compared with really performance boats the Dufour looks like one, bur it just looks, the performances are not there.
As I have said, the boat will perform well with medium winds and that's all. With very light or stronger winds the boat will not be a match for true performance cruisers.
I know that we are going to see good results in racing, but those results will be obtained not by standard boats but by racing boats made by Dufour, boats that look like the Dufour that is advertised but that will have a lot less weight....and that will cost two times more.
Brands like Dehler or Salona advertise their boats (and prices) in the several configurations they can have, regarding weight, build materials and performance. Brands like Dufour or First only advertise their performance boats in standard configuration letting you think that the boats that win races are just the same as the one you have bought
If you are a true high level racer they will have a boat for you (and probably at a correct price regarding the performance) but you go by the back door to talk with the guys that deal with that and is no use to look for that boat in any catalog: You will not find it.