Manie's Microcruiser

[Manie B]

I am surrounded by some seriously qualified degreed and educated folks around me, so calculations are no problem as we check these things from a couple of different angles. Wynand's history is well known but the day Dries publishes pics of the mega yachts that he built in Cape Town your jaw is going to drop. Fanie has got engineers coming out of his ears that also do some serious stuff of all manor and nature.

As this is an "experimental" craft, with me as the builder (read old fart) there are always more questions than anwers, and I think that is the allure or the "magic" of such a vessel / project. So the one thing that has been a HUGE SUCCESS - is it - FLOATS

So we are off to a good start
the "bucket" works and the porta potty is still in its box

Back to the future
I really like a balanced lug
I have read and read and read some more
now I love it

BUT is it the right thing to do ?
that my mates cant answer for me, I have to take the plunge and sink or swim with the budget and the consequenses.

The irony is that I cannot find ANY reference to such a rig in deepest darkest southern tip of Africa
the regulars at the yot klab pub get that glazed look in their eyes
so are they pissed
or dont they know
you will never know

Bottom line is the project has increased it "fun" index by 300 %

so here are some preliminary "number"s
they will change dont worry

Lead 10%
as per Larsson and Eliasson page 172
Ted bruwer page 56/57
your guess is as good as mine

RM approx 350 kg/m
POYD p 44/215
Dudley Dix history pages???

Empty boat 450 kg
with centerboard and bulbkeel total 600 kg
with other junk up to 700 kg total
the bulb at 160 kg is 1.7 m below water at 2.3 m from stern CLR
she is a solid heavy little beast 700 kg is no light weight

5.05 m on deck LOA
LWL 4.85 Beam 2.3 m

sail area 16.5 sqm
6m mast - 770 deep into its socket
CE approx 2990 above deck and 1010 behind the mast
so a fat thin wall mast
or a thick wall - smaller dia mast
wood? aluminium? carbon fibre?

and never forget
until somebody comes up with different info
a first for south africa
jeez I am an adventurous guy
but I have never bungee jumped and never will
and still it feels like jumping of a cliff


must be the age catching up

[Manie B]

Oh and I must add
yard 40% forward of mast
boom 15% forward of mast
luff paralel to mast

as per the experts

[Andy]

Looking good Manie. Don't know if you've seen these:

http://www.polysail.com/lug.htm
http://www.simplicityboats.com/simplicitysailrig.html
http://www.jimsboats.com/15sep11.htm

Obviously at the cheaper end of the scale, but with reinforced heavier (white) polytarp, a soldering iron with the tip hammered flat for hot-knifing, and not much time or cash you can experiment away to your hearts delight.

[Andy]

Ps for the mast I've been wondering about hollow birdsmouth douglas fir spars with thin walls, carbon fibre uni wrapped around the mast on the 90 degree axis to give 'hoop' strength and hopefully prevent buckling...again, I'm sure you can play around with your tiny stick, as it were!

[Wynand N]

Originally Posted by Manie B

Wynand's history is well known but the day Dries publishes pics of the mega yachts that he built in Cape Town your jaw is going to drop.

and there goes your boat's certification papers....

[Manie B]

Hi Andy thanks for posting, I have seen those sites, they are all good.

The general consensus seems to be to go for a 100 dia x 3 mm wall aluminium pipe. (4" x 1/8")
The advantage of this is the strength for a freestanding mast
and the huge amount of positive floatation that comes as a bonus with it sealed or filled with PU foam

The downside is big windage of a stick that towers 6m (19'8" = 4' boat and 15'8" mast) above the water, the boat already has a big windage factor for a small boat.

Aluminium pipe is strong, cheap and can be anodised or powder coated,
our local woods are poor quality and imported stuff is crazy expensive
so an "ally" mast is cheap and easy

so once again I am faced with something that is not tangible
what does a 6m x 100dia mast look like on a 5m boat
I have nothing to relate it to
I cant take a walk to the harbour to go and look around at similar rigs
the harbour is 700 km away and I will bet you a bottle of Whisky that you wont find ANYTHING even remotely close to what we are talking about in Saffa

so back to YouTube
and the input from the forum from guys that live and grew up next to the sea and have "seen" things with their own eyes

[Manie B]

Wynand thanks a million for the certificates, all good, thanks.

Ok guys now I am off to go and work on Masalai's coconut oil farm

got COF and Bouyancy and skippers and passport
papers are ready

OOOOPss

where did the mast go

hey who the hell forgot the sails

damn still no crew

[Manie B]

I have updated the CAD drawing
to show a stick 4" dia 20' above the water

doesn't look too bad
just dunno

it's Sunday afternoon here
time for a beer and barbeque
tired of worrying about an ally pole

got a good idea
show my big stick to some "crew"
still love wicked weasel

[troy2000]

Originally Posted by Manie B

I have updated the CAD drawing
to show a stick 4" dia 20' above the water

doesn't look too bad
just dunno

it's Sunday afternoon here
time for a beer and barbeque
tired of worrying about an ally pole

got a good idea
show my big stick to some "crew"
still love wicked weasel

Is that you lying in the boat, Manie? Looks like you've lost a little weight.

[Wynand N]

Originally Posted by Manie B

Wynand thanks a million for the certificates, all good, thanks.

You're welcome, anything for a friend

Manie, let me have the righting moment of your boat @ 30 degrees heeled, mast height you looking at and chain plate width (across deck) and I will calculate spar moments of inertias for you if you go the ally way;

1. free standing
2. Stayed with one spreader pair (keel stepped).

OTOH, I would go for a hollow wooden mast and will do some calculations and basic drawing on how to build and let you have the lot and then you can decide which material and type to use.

[Wynand N]

Originally Posted by Manie B

Fanie has got engineers coming out of his ears that also do some serious stuff of all manor and manure.....

care to explain?

[Manie B]

Wynand the idea is a free standing mast
my math is hopelessly outdated to calculate RM, so I am guestimating
mast heights are on the drawing
and all other dim in previous post

[rwatson]

sigh - the spirit of "lets stay confused because its exciting" reigns in SA.

Its fun to make decisions based on "I read it somewhere" , but to my mind, the height of the mast and the sail area come well after someone smarter than me knows how much wind it will take to blow your "bliss box" on its arse. For someone so careful to make a seaworthy boat, it seems the mast/sail design business is a wee bit .... "hit and miss"

Now, does the lead weight and keel length get calculated before, or in conjunction with, the mast/sail calculations ? So many decisions ...

Aww .. bugger it, rip a rig off an old 20ft yacht, hang a bag of bricks under the hull, and see if it works !

[Manie B]

no its not that bad
we got a lot of info

still just thinking out loud
she will come upright

floats high and dry on its side

one guys tender is another guys responsive
your guess is as good as mine

[masalai]

Hi Manie,
Do you still need to see what a 6m length of 100mm mast "looks like" - how about some plastic down-pipe or drain-pipe from your friendly plumber supply/hardware store? - - it may be grey or off white but here a popular size is 100mm...

Best wishes and C U soon...