MilliBee with a haircut?

[Paul H (admin)]

These times of austerity demand cut backs across the board - a slight remodelling of MilliBee comes to mind to:

1) Reduce windage, something you will appreciate when she drifts sideways into a river bank at the most embarrassing time possible.

2) Get rid of the underwater brakes (bilge cases) that Chris W. thinks should be replaced by an efficient shaped centerboard.

3) Give more clearance for the rig.


Its a quick mockup - the most amusing reply gets a free pint at Beale (if I can remember which bus to take). Serious suggestions are welcome also



-Paul

[Timmo]

Less windage, centreboard, rig clearance... sure, very interesting and sound like great ideas.

Much more important is the antigravity! Getting it to hover 30 cms above the trailer is an amazing achievement.

Tim

On 8 Feb 2012, at 22:20, adminHBBR [via UK HBBR Forum] wrote:

> These times of austerity demand cut backs across the board - a slight remodelling of MilliBee comes to mind to:
>
> 1) Reduce windage, something you will appreciate when she drifts sideways into a river bank at the most embarrassing time possible.
>
> 2) Get rid of the underwater brakes (bilge cases) that Chris W. thinks should be replaced by an efficient shaped centerboard.
>
> 3) Give more clearance for the rig.

[Anders]

You forgot one thing: It looks so much better. Very close to the original and actually better.
I can imagine that its all about how much you use the cabin. Shaving 15 - 20cm off and having a centerboard case in the cabin means less space, so I can imagine you dont use it so much. Is it mostly for the kids.

[alopenboat]

You need a bit more ballast, methinks.


On 8 Feb 2012 at 14:20, adminHBBR [via UK HBBR Forum] wrote:

>
>
> These times of austerity demand cut backs across the board - a slight
> remodelling of MilliBee comes to mind to:
>
> 1) Reduce windage, something you will appreciate when she drifts
> sideways into a river bank at the most embarrassing time possible.
>
> 2) Get rid of the underwater brakes (bilge cases) that Chris W. thinks
> should be replaced by an efficient shaped centerboard.
>
> 3) Give more clearance for the rig.
>
>
> Its a quick mockup - the most amusing reply gets a free pint at Beale
> (if I can remember which bus to take). Serious suggestions are welcome
> also
>
> http://uk-hbbr-forum.967333.n3.nabble.com/file/n3727803/milli.jpg 
>
> -Paul
>
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--
Hoping for calm nights

Alastair Law,      
Yeovil, England.
<http://www.little.jim.freeuk.com>          

[Chris Waite]

"Is it a boat, is it a plane?"

Will that do?

And when do you start?

CW

[Paul H (admin)]

Anders wrote

You forgot one thing: It looks so much better. Very close to the original and actually better.
I can imagine that its all about how much you use the cabin. Shaving 15 - 20cm off and having a centerboard case in the cabin means less space, so I can imagine you dont use it so much. Is it mostly for the kids.

Anders,
The cabin was certainly over-engineered, but somewhat accidentally. She was built in a U shaped space boxed in by my shed and two fences so it was impossible to get a true side view of her profile during construction. I raised the roof for more headroom, extended the cabin thinking that the kids would enjoy the extra space made even bigger by the bilge cases hidden under the bunks. I hoped that would make them feel more comfortable hoping for family based cruising.

However, the cabin has obviously turned out to be a tad big. Some people said that is a good thing for such a small boat and they like the roomy interior. Hard core open boat sailors immediatly remark about the higher windage she will suffer and they are infact correct. No boat is perfect though, and in reality I am the only person to have slept in her despite carefully planning the cabin to sit 2 adults + 2 kids, with the kids sleeping in a boom tent. The kids have grown up now, so streamlining for just one or maybe two people is probably a good thing.

The "Chainsaw Massacre" might make its way onto You Tube ...but probably not this side of 2013.

-Paul

[Paul H (admin)]

Timmo wrote

Less windage, centreboard, rig clearance... sure, very interesting and sound like great ideas.

Much more important is the antigravity! Getting it to hover 30 cms above the trailer is an amazing achievement.

Tim,
Anti-gravity was easy. I picked up a mothballed Star Wars speedster on ebay and stripped it down to the essential hardware (plans available if anyone is interested).

<

-Paul

[Anders]

Paul, Its the classical problem: ¿making sailboats or sailcaravans?  On 14´ even 10cm higher looks big.
Am a right when I read that you´re not a big fan of Paul Fisher L shaped bilge centerboards? Is it one of these things that look fancy on a drawing but doesnt really work in reality?
I ask because maybe in the VERY far future, I could be interested in building a pocket cruiser.

[Timmo]

Cool!

Even beats an electric bicycle. can it be solar powered?

Tim.

On 10 Feb 2012, at 21:08, adminHBBR [via UK HBBR Forum] wrote:
> Tim,
> Anti-gravity was easy. I picked up a mothballed Star Wars speedster on ebay and stripped it down to the essential hardware (plans available is anyone is interested).
>

[Paul H (admin)]

MilliBee is indeed an excellent sailcaravan and the L shaped bulge boards certainly work - less rudder is needed when one or two are lowered.

She sails upwind better than a Paradox, but a Mirror beats both. She is poor in light winds, I think that is due to the Enterprise rig lacking power due to inefficiency of rigging over the bulky cabin - hence it struggles to overcome the higher hull drag caused by the bilge cases.

But in medium winds she flies, the chines dig in as she heels so I can point higher with good speed.

My biggest grumble is the high ride height on a trailer. To recover her the trailer often must be totally submerged and she must align exactly with the bilge rollers - there is no element of self centering that you get with a traditional roller setup. The bilge rollers take all the weight so the brackets bend, perhaps U channels lined with carpet would be a stronger solution.

However no boat is perfect and I can say the accommodation is first class, and she is excellent in a river or harbour.  

I have no idea how the performance improves with a centreboard. A rather dramatic experiment is needed to find out the truth! However logic says that, with all things considered, the change would be positive.

Cheers
Paul

Sent from my HTC

[Paul H (admin)]

This time its for real folks - Cee Dubs will be jumping for joy when he reads this post.

The bilge cases (aka underwater brakes) have been trimmed by 140mm using my new Bosch Professional jigsaw that coped very well. It's amazing how low she is now - launch/recovery will be much easier of course.



Initially they are level with the keel for drying out flat:



The next stage is trials with temporary vertical daggerboards in the existing slots to get a feel for the correct centreboard position.



Cee Dubs thinks the CoE of a centreboard should be 10in behind the bulkhead so the trials will give valuable feedback.

-Paul

[Port-Na-Storm]

Excellent start, now why not lower that coachroof back to where the designer intended it and lose some of that windage?
Presumably it also means you've lost the heavy metal plates. What will that do to the balance?

Sea trials and experimentation at Cobnor? I'll bring a chainsaw.

[Paul H (admin)]

Graham,

The plates weighed 26kg, but the bits chopped off gave about 5kg of buoyancy so call it 21kg lost. I estimate it was only 25cm forward of the centre of gravity - that sort of weight needs to be much further forward. Swapping it with a water tank or water ballast or something else forward of the mast is a positive move.

Might be able to do some trials before Cobnor...

Paul

[Jeremy]

Looks a lot better, Paul.  I bet all you notice is an improvement, with no downsides, as I strongly suspect those keels were adding more drag than lateral resistance.  Mind you, I have a pathogenic hatred for bilge keel boats, having once sailed an old bilge keel Silhouette.  

My guess is that some simple dagger boards would work better than the old plates, too.

[Paul H (admin)]

Illusion's 9mm floor has been recycled into some rough and ready dagger-boards - about 3ft in the water with an area of 0.25m2 each. They should clear the boom if my memory is correct:



Cliff Martin (DCA Mirror expert and hard-core sailor) suggests a centreboard area of 4% of sail area - which is 0.4m2 for an Enterprise rig.

There is a bit of flex in the dagger-boards of course. Do I really need to laminate them thicker just for trials?

However if they work and clear the boom its worth the laminating/shaping and they could become semi-permanent.....

-Paul

[Jeremy]

I reckon you might well break 9mm ply, but maybe it'll just flex a bit for your trials.  Not worth shaping it if it's just an experiment, but if you don't want to risk breakage I'd thicken them up a bit, maybe by laminating some thin ply either side?

It looks to me as if the boat was designed for a system like this, much neater and potentially far more efficient than the original set up.  The boards don't really get in the way much when raised, either.

[tony waller]

They certainly look a bit bendy. Would glass fibre each side stiffen them up enough? Tony

 

From: adminHBBR [via UK HBBR Forum] [hidden email]
Sent: 19 June 2012 21:57
To: tony waller
Subject: Re: MilliBee with a haircut?

 

Illusion's 9mm floor has been recycled into some rough and ready dagger-boards - about 3ft in the water with an area of 0.25m2 each. They should clear the boom if my memory is correct:

[Paul H (admin)]

Jeremy, Tony,

The original Lynx14 design had lifting dagger-boards. They where built into the cabin forward of the bulkhead which in my opinion wrecked the internal space, so I copied the bilge keels from the Lynx16 design.



But Cee Dubs and myself think the board's CoE should have been further back behind the bulkhead - every boat is a compromise though.

I have scrap 6mm ply from Illusion's sides so I'll laminate the 6+9 together. The bottom of Illusion was heavily glassed so keeping that side to leeward will prevent breakage.

-Paul

[Jeremy]

My experience is that, as long as you're not a perfectionist, you can get away with having the lateral centre of resistance vary over quite a wide range with only modest effects on the helm.  There are all sorts of stories of boats with lee helm being dangerous (I agree, but haven't ever found one), but I'm not sure it's really that easy to get the whole boat centre of lateral resistance that far aft as to get to that condition, particular on a boat that's relative flat sectioned aft anyway.  

Again, in my opinion (YMMV) too much weather helm is truly evil.  My old gaffer was a bitch in a blow, and needed both hands on the tiller to keep her up into the wind, unless you shortened sail to the point where you weren't going anywhere quickly.

[Port-Na-Storm]

Look at that sleek low coach roof the designer intended. Mmmmmmmm

Of course lowering the roof will lower the tabernacle so the boards may argue with the  boom.

Dagger boards are all very well but the do have one major drawback.
I presume you intend to sail her with both boards down otherwise the windward board is going to be just where you want to sit. Similarly when you are dried out on the mud they will need to have a home. Maybe they could become sides for the tent?