Manie's Microcruiser

[Manie B]

oh and just to show that I am not a complete goofball
I didn't move the position around of the centerboard

that is the only thing that is millimeter accurate
jeeez thank goodness for that!

[Manie B]

please you must watch this video of Scamp
this is where the Magic is
take note of how the boom reefing works
very clever

http://www.youtube.com/watch?v=GomIA...wcZkDXkWx8EV5b

[rwatson]

Originally Posted by Wynand N

Funny you posted the link to your past built because...or, rather let me quote

"I had no plans, just a few pictures of a Wharram Catamaran

It was a lot of trial and error until it worked properly."

Yeah - but you conveniently left off my most pertinent remark

"... which is the reason that my current project is getting the full design completed before a single plank is cut."

I have learned my lesson - Manie is still half way through his .

Originally Posted by Wynand N

At least Manie did not have trail & error issues - we speculate, then calculate and finally pray before doing it...

No trial and error ? He still has to finagle you into calculating his scantlings for the major structural element of the entire boat (hey, whats the chance of getting insurance on this prototype over there ? ) - so he may be forced to break into his lovingly painted and sanded interior to do some major work. That sounds like fun - NOT!

Then, he still has to sort out the sailplan and all the associated mast and rig setup problems.

Like Manie just said once power supply was restored "because we all know a major change like this, so late in the build, is scary."

If that's not trial and error, what is ?

And Troys comments :-
"It's easy to sit in the shadows and potshot those who are actually doing something...."

Yeah - of course it is - thats why I am doing it !!!

Whaddya ya want ? Do you think I am silly enough to spend 3 years in my carport sucking in sawdust and epoxy dust, and having to keep the place looking like Martha Stewarts show home ?

What fool would do that ?

My biggest worry is having Manie out in the shark infested waters of the Southern Ocean with the little putt-putt, a sail rig that is still under test, and 200 kilos of prime steel hanging off his arse that may or may not stay there if the waves and wind get any bigger.

If the worst happened - what a waste of steel and epoxy !!!!

[masalai]

Arrrrgh I would be disinclined to put much in the criticism of RW... No build recorded... - and Australian banks do borrow heavily overseas...

[Doug Lord]

You've done great, Manie-good luck and good sailing! Maybe I can get my damn boat figured out......

[Manie B]

rwatson your "concern" is appreciated and ok thats enough now, the comments are going around in circles

[rwatson]

Originally Posted by Manie B

rwatson your "concern" is appreciated and ok thats enough now, the comments are going around in circles

You're right - however you got there, you are further ahead than 98% of small boat builders. Well done - and you get an "A" for perseverance.

You may not have ticked the boxes in exactly the right order - but you have all the boxes lined up neatly in front of you, which is half the battle.

And as you say - making it up as you go is a lot of fun

[Wynand N]

Manie, you said it well.

Many people are content with their daily grind middle of the road monotonous lifes, living from day to day awaiting their salary pittance on pay day. They conform to what is proven and stay within those "laws" that makes their world go round. It is also called a comfort zone....

The problem with comfort zone holes are although you sit snug in it you views are also limited to the sides and you do not see much else. Getting out of that comfort zone however, the containment sides of the zone give way to a much wider world, challenges etc but since you are not snug in the zone anymore, the ride may be more shaken...
When faced with a bigger vision out of the comfort zone, life becomes more interesting and as mentioned, more challenges there for the taking and suddenly life get worth its time.

Basically all the comforts and technologies we have today and take for granted, is the result of someone getting out of the box and taken some risks. Most probably some of them were laughed at when they build and risk life and limb trying out their ideas. Like the saying goes; "nothing ventured nothing gained" and most of the time that is true.

I had a laugh when reading the concern that you may end up being lunch for the sharks - heck, first off they have to be starving and hard up before attempting to lunch on your bacon and at the end of the day, we all have a date with death once in our lives and why not cash that in doing something you like...
In fact, you stand a better chance to get murdered here or being run over by a car than ending up on the sharkie menu.

For what its worth. I once (late 1980's) built a steel boat (design by a well known international design group in Europe) for a client and after the hull plates were done, he wanted a totally different deck for the boat, interior, sailplan etc. and the plans dumped because for what he want, they are now obsolete. At the time I had not done my small boat design diploma yet, IOW, no frickin clue on how much here and there to add or take away, less more so my client, but being a boilermaker by trade, I did the best I could with my knowledge of steel and the boat is still sailing the oceans.
My mentor at the time as a greenhorn boatbuilder, and he a boatbuilder of the old school, the late Ronnie Nel from PE once told me early in my career; "Wynand, if it looks right, in most cases it will be right" and this I found rung true through most of my building career.
Quite often I will make an amendment to some structural part on the spur of moment by the "look right" method and when run a scantling calc on the part later, it would be usually OK or in excess.

Ask yourself this question; before man became clever, using maths, employing computers, how did they know the boat structure will be OK?? I would venture and say the used old Ronnie's method "if it looks right, it should be right".
Also true, most small boats are immensely strong compared to their larger sisters and are usually overly strong built and yours falls definitely in that category.

Finally, forget the nay sayers, focus on your own thing and if something look and feels right to you, it most probably is. At the end of the day it is you that should be satisfied with the results and screw everyone else.

[troy2000]

Originally Posted by Wynand N

My mentor at the time as a greenhorn boatbuilder, and he a boatbuilder of the old school, the late Ronnie Nel from PE once told me early in my career; "Wynand, if it looks right, in most cases it will be right" and this I found rung true through most of my building career.[/B

Although I'm not a professional boat builder, I've built a lot of houses, garages, decks, sheds and whatever in my lifetime. And I'll agree wholeheartedly with that statement, with one caveat: you need to have enough experience to understand WTF you're looking at!!

[Manie B]

Although I'm not a professional boat builder, I've built a lot of houses, garages, decks, sheds and whatever in my lifetime. And I'll agree wholeheartedly with that statement, with one caveat: you need to have enough experience to understand WTF you're looking at!!

How true!

I have been thru a very lousy time the past 4 years with many of my very close mates passing away. That is why I decided to start a Facebook page, this turned out to be a bit of a CV and also the history of my working career.
To some this may seem a bit crazy, but I am what I am and did what I did. Some good some not so good.

Anyway this is the "info paragraph" from Facebook

I have started this Facebook page to try and find some of the old friends and colleagues that I have worked with over the years. There were many good days and some seriously pleasant memories. Love to know how all of you have held out and hoping you are healthy and well.
I have been in my own businesses since approx. 1980 and still at it! I still dream of sailing solo around the world one day!
Read all about my hobby at www.compaxboats.wordpress.com

You can read more on Facebook - it is open public knowledge - got a bit of experience

Manie Botha

http://www.facebook.com/profile.php?id=100003491689969

[Wynand N]

Manie, just browsed your keelbox installation on your blog and glad to say that I am overly impressed with that piece of engineering
http://compaxboats.wordpress.com/201...-board-casing/

It is in fact - by just looking at it, overly designed to support a small 160kg bulb hanging 1.1 meter below bilge. You did good by reinforcing the whole area with Kevlar etc and I like the fact the casing protrudes 25mm through hull. Also nicely supported at the top and the fact that the casing also protrudes 25mm through the deck - the keel has to move the deck before that case moves.
Furthermore it is solidly bonded and supported by the two main transverse bulkheads vertically fore and aft of keel box that will distribute loads imposed by the keel over large areas of the hull. The furniture (locker) that is attached to the casing about midway up and also solidly bonded to the two mentioned bulkheads and the hull side further stiffen it up immensely and all work very neatly done

This is what I call a decent piece of (engineering) design and execution thereof and most likely way over designed for what it suppose to do.
However, I think you must rather spend your energy now on designing a decent centreboard that will handle the bulb safely without breaking. Think steel (ss) reinforced and carbon fibre unit...

Just my sentiments for what its worth

[Angélique]

Hi Manie, congratulations on the outcome of the stability calculations

About the bulb, 160 kg requires 20.3 dm³ steel or 14.1 dm³ lead. Maybe someone can estimate or calculate how much the bigger steel bulb vs a lead one will slow you down. If not much, no problem. If more, you might reconsider . . . . ? ?

Question about the stability, one of the advantages of a centerboard is you can pull it up in a gale to be able to be pushed aside by the seas rather than trip over the board/keel which causes the knock downs when the sails are down. In this case you also pull up the ballast. What would be the stability with the board up ?

Wynand, please keep up the good work

Cheers,
Angel

[Angélique]

BTW, saw Dudley Dix uses beavertail bulbs rather than pointy ones.


Didi 28

Is there someone who can tell me the benefits of beavertail vs pointy ?

What form are you gonna use Manie ?

Good luck !
Angel

[Manie B]

The centre board was the first item that I built before I even started with the boat.
Because from that I built the "casing"

The center board is

6x layers of 9mm marine-ply laminated
1x center core of carbon fibre
2x outer cores of kevlar
2x far outer cores of 600gm bi-ax glass

and then the whole lot wrapped in 750 gm glass

[Manie B]

The "design" of the lifting centerboard was primarily for towing, the added bonus was to be able to go motoring into very shallow water.

see post #9 and #10
jeez this thread has been running so long that we all forget where it started