In relooking around I notice some more photos and information on the P&H Venture Skudder:
In Richard Wilcox's blog:
http://seakayakphoto.blogspot.ca/2015/10/p-skudder-long-term-test-of-sea-kayak.html there's some additional photos and info:
and the following comments:
"Unlike the more expensive Kar-itek skeg/rudder (which I have used over many years) it does not self centre as you lift it. This means you need to centre it with your feet first."
which is as suspected in other post mounted blade systems:
The resolution looks fairly clunky with the rudderpost penetrating up through the deck. And like the lettman (although I cannot tell for sure as for the lettman) it looks like a hunt-and-peck retraction with a centre-detent. ie not a self centering on impact mechanism.
From Richard Wilcox's comments, it seems as though it doesn't have the detent or bungee centering that Thomasson has considered with his almost identical approach. The advantage of the Thomasson approach is the large post has wider support to keep the blade from wobbling or getting post wear - as you can easily see happening in the P&H Venture at 0:59 of
.
[The Thomasson disadvantage is, when deployed, that large post's geometry intrudes into the slipstream.]
also there was an earlier surmise:
the keel-line is not continuous so there must be some larger cutout for size of the rudderpost and "shock protected joints"
shown here - similar:
Which all sorta brings me back to Mac50's comment a few posts back:
About 15 or more years ago we had Don Currie fitting such rudders to Skerries.
because this approach is so extremely basic and has been used by so many [as one can see from all the examples in this thread - Lightspeed, Lettman, Fibreline, Thomasson, Currie, etc] that you have to wonder how it is to be patentable at all. What's to patent: tiller?, post?, blade?, retract? - maybe the shape of the 'slot'?? [if it was me, I'd patent a deployable detent - or cam the post top]
So far, the only sophisticated system that has been available [now not, I think - [pun: it's been retracted]] is the Karitek SkegRudder. Sophisticated in that if the blade is hit from below, its mechanical design requires it to
automatically centre and then retract into an
actual slot in the hull of the boat. It was too big, expensive, and clumsy, but the
design was the most sophisticated.
But I'll comment for a bit about the 'skudder' and the 'skeg-rudder' naming and design approach:
Possibly the most important advance in boat rudder design is the stem-
mounted rudder blade. This was a major advance because all of a sudden the relatively fragile blade and rudder assembly was very well protected and extremely well supported by hull shape and extremely strong stem-frame. We typically hear of the importance of this central rudder placement advancement - but it wasn't the central placement that was the advance - that has/had been done for thousands of years: ancient egyptians [we're learning], the chinese, etc - it was the strong, protected location in a vessel whose waterlines necked down at the stern [ie skegged] so that the rudderblade did not have to be exposed below the hull to be effective. All of a sudden permanent mounting was possible whereas before huge, huge dismountable rudders were necessary [some shown previously in this thread] that dipped deep into the water outside the parameters of the hull.
And now with the presence of deep shortened keels such as in many sailboats, rudders have often been separated from those keels in order to achieve the best turning moment, but with this approach there has always been concern about the now newly exposed rudder. This exposed rudder is often called a 'spade rudder', but because of that possible damage exposure, a slightly different approach is used with small strong skegs built right in front of the blade that take some of the hydrodynamic loading, but much more importantly protect the fragile blade and change the structural concept of the blade from one of a cantilever to that of being fully supported along its length - huge changes of duty.
So same thing . . . . . why the &^%$ don't we have deployable skegs that have those fragile blades mounted
behind them so they can take a little abuse?
That's what a 'skeg rudder' should be. That's what a skeg mounted rudder is anywhere else but our funny little kayak world. Would operate the same, would perform essentially the same, but would be as strong as that big skeg hinge. comment over. TMI probably