Solve debate, displacement or semi?

[denverd0n]

Originally Posted by SVHarmonie

How many angels can dance on that pin?
How exactly do you define “semi-displacement”, and who cares anyway?

This ^^^^

[valhalla360]

Originally Posted by StuM

Has anyone ever seen a semi-displacement monohull cruising sailboat?
I don't know of any.

Yep, usually associated with trawlers. Most sail boats don't have enough HP to utilize the "semi" part.

The real proof is does it lift up and significantly exceed hull speed if you pour the power on. If a 40ft sailboat tops out at 7.5kts under power, it is at best an academic discussion.

[StuM]

Ah yes, I forgot about the MacGregors

[thinwater]

Originally Posted by StuM

Displacement - the aft section if far from flat and wide and there' no way that thing will be able to get above displacement speed.

This.


You can even feel the difference on multis that use flat sections vs. skinny sections. Both can be fast, but the relationship to wind speed is different. My F-24 gets into an obvious speed hole at 6.5 knots... and then it creeps up over 7, and then you are going 10 knots and planning cleanly from there on out. The aft sections are flat with little rocker. The PDQ, on the other hand, has round sections and moves up in speed more smoothly with a less obvious planning "jump."