re microcruiser

Dom, re your weight budgets. You can do better than 10kg per sq mtr with a ( for example) 8mm foam / doublebias or biax / vac bagged lay up , hull skin

 
Suggest revise your estimates . Conceptually your micro is interesting but given that the current LW hull on elementarry weighs in at 30 kg approx ( Rob, correct me if I'm wrong here ) I think you would need to revise your comparative weight/displacement relationships.

regards
Paul Napper

-----Original Message-----
From:   dominiquebovey [SMTP:dominiquebovey@...]
Sent:   Monday, 7 February 2005 8:05 PM
To:     harryproa@...
Subject:        [harryproa] Re: Elementarry micro-cruiser




--- In harryproa@..., "proaconstrictor"
<proaconstrictor@y...> wrote:
Hi Proaconstrictor,

Thanks for your remarks.
And Rob, what do you think about this?
regds
Dom

>
> We did explore the idea of a micro cruiser not that far different
> from what you are describing on a 16 foot platform: Imagine a Jarcat
> with hulls going both ways, and bow sections that bolted on to extend
> the lee hull to 20 0r 24 feet.It was quite an active thread on the
> yahoo Multihull Boatbuilding group.  I don't doubt something of the
> sort can be arranged.
>
==> me too!

> You can get what you are after two ways for starters.  A completely
> different design from elementary.  Or an elementary with an entirely
> inappropriate sidecar.  I mean you can bolt anything you want to the
> side of an elementary, and it wouldn't necesarily be that bad an
> idea.  In other words it might be a fast Bolger Micro, I just can't
> see it being a proportional elementary, with reasonable performance
> etc... 
No the micro-cruiser would not be a high performance boat but it
hasn't to be! Don't forget you still keep on the trailer the bare hull
for speed runs and the camper hull for a bit more extended racing/less
ambitious cruising. It is exactly this "modularity" (as we engineers
say) which in my sense is interesting in the harryproa concept: you
have a "kit boat", and you use changing parts (different ww huls,
different masts/rigs) depending on how you use the boat, for example:
- the bare ww hull with the big rigs for Lake Geneva sailing on a hot
summer day with 2Bf max
- the micro-cruiser hull with the small rigs when sailing in corsica
where you suddenly may have Bf7 even on a beautiful day
- or the camper ww hull when the race last more than a day and you
need some very limited sleeping accomodation.
- etc.

> I also think that once you go sufficiently far in a
> particular direction it may still be conceptualy a proa, but it
> starts to loose the "Why is it actually better than a Farier 18 or a
> jarcat 16" race. 
In my view it is better than these because of the modularity as said
above. You can't easily tranform a lightweight trimaran in to a
cruising one: I feel on the contrary it is possible with harryproa.

I mean the original, long gone, Harryproa was
> supposed to be better than something in an equal weight, cost, speed,
> nausea resistance, building time bracket.  About twice as good as I
> recall. 
It still is! And with the added advantage that it is not a "fixed
function" boat.

> Not every boat wants to be a proa.  In fact there is little
> convincing evidence of any boats that really need to be proas.  Get
> too far from the sweetspot, and it just doesn't make sense.
I think I feel what you mean - and I agree with it.

>
> Anyway, my quibble was intended to be objective.  You had a long
> list. I can't get that stuff on my 24 foot trimaran, literaly.  It
> all starts with displacement.
I agree, you can't have that on a trimaran because much space is
"wasted" for the chassis and so can't be used for accomodation - as
the trimaran is less than ideal than the harryproa concept!
Comparatively more structure is needed in a trimaran for the "chassis"
of the boat than in a harryproa.

The things I listed would find place in a 5.50m "micro" class monohull
it there was no cockpit. And there is no cockpit in the hull of a
micro-cruser elementarry, this is how you can put two double beds in
it, one on each end. But don't misunderstand me, there is almost no
floor space, around 0.5x0.5m just for 3 persons sitting inside and not
more.
The porta potti finds its place under a a lifting part of the beds,
exactly as it is fitted in a 5.5m micro monohull, the battery and 30L
of water on the other side.
About displacement. I think you can count on about 10kg weight per
square meter of "hull skin", using a not too high-tech way of
building. I estimate the skin area of such a ww hull at 20m2, that is
200kg for the bare hull. Add 60kg for battery, wiring and water, 20kg
for the WC, and a small cooker, VHF, etc to a total of 320kg. Add
200kg crew weight (a couple with 2 smallish kids), 100kg for lw hull
and rig, and this amounts to a total loaded displacement of 620kg. It
would certainly not be a racing boat - but would still a fine cruiser.
Rob, tell me whether/where I am wrong here?








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