G'day,

 

Don't be fooled by the reverse sheer and the spray washing over the bows.  It is nowhere near it's limits, in fact, it has barely immersed the bow past the waterline.     Harrys have huge amounts of buoyancy in the bows due to their prismatic coefficient (a measure of buoyancy distribution) of 0.8.  Most cats are in the 0.6-0.65 range.   With the rounded decks and nothing to slow the boat (fore beam, trampoline, forestays, etc) it goes through waves very easily.

 

Not sure if you mean heel or pitch.  Some of both are inevitable.  As the lee hull waterline at the bow is just out of sight and at the stern a couple of inches are showing, I would estimate a couple of degrees of heel, and less of pitch.  The absence of heel is confirmed by the angle of the stainless lifeline against the horizon.  Mark reckons it pitches and heels less than any boat he has ever been on.

 

The video is indeed sedate seas.  Not much we could do about that.  In bigger seas, my experience with my boats is that they go through waves with no noticable effect  (ie, you do not feel the boat slowing).  This boat is bigger and heavier, may have even less effect.  What is noticable on my boats, and to a lesser extent on Rare Bird, is that waves hitting the rudder cases do noticably slow the boat.  Only happens at high speeds, with large waves and is caused by the cases, rather than the brackets, and it has been addressed in later designs.  It is evidenced by the creww feeling a small jerk each time it hits a large wave.  As you can see by looking at the passengers, there is none of this. 

 

The rudder brackets have so far proven to be plenty strong enough to take the loads, including running aground at speed with the wooden sheer pin replaced with a large steel bolt, causing case damage.

 

In 25 knots with big seas?  Time will tell, but on all my prototypes, it has not been a problem. There are not many cruisers that sail consistently and comfortably at 15 knots, much less higher speeds. Rare Bird has punched through a wave that washed items off the boom (>10' off the water) while crossing the bar, with no ill effects.

 

Great that you have advanced from "no good at all speeds" to "good at 15 knots wind, 15 knots boat speed", and I appreciate your ability to accept evidence.    I look forward to convincing you about the next step. 

 

regards,

 

Rob

 

 

On 8/9/07, Todd <bitme1234@...> wrote:

No I don't think a flared bow would be any better.It would be worse.
The boat doesn't look to be sailing flat. It looks to me to be
heeled 5 to 7 degrees maybe more in the video. To me the leeward
hull just seems to shallow at the ends. In the 1 metre swell the bow
is punch through on a few all most buried. The video shows pretty
sedate sea state and the boat looks all ready to be pushing its
limits with the leeward hull low in the water. Along with the
appendage attachments. Load of rudders horizontally and vertical in
proper trim but what about at speed, 20knots being pounded
vertically hour after hour. In and out wave after wave?

Good at 15 knot winds 15 knot boat speed but what at 20 to 25 knots
in lumper seas?

Todd

--- In harryproa@..., "Robert" <cateran1949@...>

wrote:
>
> The boat looks as though it is riding pretty flat to me . With 3m
> swell I am assuming the bow will simply punch into it and gently
rise
> without any violent hobby horsing. The flat ride should keep the
sails
> working better than with violent motion of a flared bow bouncing
off
> waves I can't think of any small boat that would not be pretty wet
in
> the same circumstances. The braces are designed to take the loads
of
> the rudders. Shock loads from the braces hitting the top of the
wave
> is nothing compared to loads from the rudders,
> Robert
> --- In harryproa@..., "Todd" <bitme1234@> wrote:
> >
> > --- In harryproa@..., "Todd" <bitme1234@> wrote:
> > >
> > > Hello Rob and folks, (sorry about that)
> > >
> > > Nice video, impressive. But;) Looks like 1 metre swell
possible in
> > > 15 knot winds for a boat speed of 15knots . Marshall Island
Walap
> > > will do that. What about 25 knot winds in 3 metre swell? Looks
as
> > > throught the bow is pretty close to the edge in 15 knots. As
far
> > as
> > > all out performance pushing the boat to the limits what is
known?
> > >
> > > What about the braces for the weather boards, how much abuse
will
> > > they handle being punched from underneath or swist from
changing
> > > angle of attacks in certain situations. The bottom brace seems
> > > really close to the water surface.
> > >
> > > Todd
> > >
> > > --- In harryproa@..., "Rob Denney" <harryproa@>
> > > wrote:
> > > >
> > > > G'day,
> > > >
> > > > My Harry did 15 in 15 with lousy sails, but not much
interior,
> > so
> > > probably
> > > > pretty similar. Blind Date will be faster than Rare Bird as
it
> > is
> > > lighter,
> > > > has less windage and a stiffer mast. Rare Bird's sails also
> > need
> > > some work,
> > > > it has not realised it's full potential yet.
> > > >
> > > > The only real difference in a Harry is whether you have the
> > > cockpit cover or
> > > > not. Bain has it and it works well. I prefer to feel the
> > breeze,
> > > so the
> > > > solo boat will have a pram type fold up cloth cover over
part of
> > > the cockpit
> > > > for keeping out of the rain and wind.
> > > >
> > > > regards,
> > > > Rob
> > > >
> > > >
> > > > On 8/8/07, George Kuck <chesapeake410@> wrote:
> > > > >
> > > > > How will the 12m (40') Harry (built with the KSS
method)
> > > performance
> > > > > compare to Rare Earth or Blind Date ? Will it have
> > a "cruiser"
> > > or "sport"
> > > > > version option or be a compromise between the two ?
> > > > >
> > > > > George Kuck
> > > > > Chestertown, MD
> > > > >
> > > > > *Robert <cateran1949@>* wrote:
> > > > >
> > > > > It is pretty impressive for such a comfortable boat. Even
> > with
> > > the
> > > > > extra weight it is still pretty light compared to most
> > > multihulls of
> > > > > similar length,
> > > > > \ Robert
> > > > >
> > > > > --- In harryproa@... <harryproa%
> > > 40yahoogroups.com.au>, Mike
> > > > > Crawford <jmichael@> wrote:
> > > > > >
> > > > > >
> > > > > > Fifteen knots in fifteen knots of wind? In Rare Bird?
Holy
> > > moly!
> > > > > >
> > > > > .
> > > > >
> > > > >
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