New Bi-Rig Performance Cruiser

[fastcat435]

Hallo Alan

we build our cats on electronic load scales and during that process we move weight around to get the boat as good as possible balanced.
The weight we actually measure our cats at are actual weights.
Including all equipment for ocean crossing including the following list

Sterling fast charger
Air Breeze wind generator masthead mounted 300 watt 24 volts
LCD TV screen connected to radar screen for large picture 26 inch
Dolby surround system multi system for world wide use
Multi region tv/fm antenna with mast bracket suitable for digital TV
Capi2 power distribution system
Active radar deflector detector
Raymarine GPS/plotter, radar 8" and 12 " color + interface to LCD screen
Watermaker 16 gallons per hour 24 volts manual
Victron 2000/100 inverter / charger .
Mobilert active overboard alarm system for 6 people type 7600
Davits aluminium with lines and blocks
Debug for engines or generator (against algae in diesel)
Autopilot self learning
Floscan digital fuel flow meter with total consumed diesel
1 x Solar panel 210 watt .

safety

Book Doctor on board
First Aid Kit (Extensive)
Outboard 2,3 hp 4 cycle
AIS system to monitor other shipping around
8 fenders 8 mooring lines 4 mooring lubbers
Lightweight rigid inflatable 10 ft long 4-5 persons
Safety outfit lifejackets safety harnesses life lines
Spare anchor (Rocna)15 kilos plus 10 meters chain and 50 meters line
Anchor bridle with stainless steel connecting plate
Life raft light weight for 6/8 pax

sails

Gennaker with lines and blocks 135 M2
Gennaker with lines and blocks 95 M2
removable bowprod with spectra waterstays 80 m2
Storm Jib with Velcro connection
Sea anchor/Drogue (for heavy winds)

kitchen

Side by side fridge freezer 200 L.
Freezer 50 gallons w. cooled in saloon seat
Extra gastank composite
Polycarbonate glasses 24 x
Nespresso coffee machine by Magimix
Dualit Toaster
Kitchen machine
Hardwood cutting board installed above dish rack
Light weight washing machine ( 3 K . )
Light weight set Dinnerware for 8
Nesting Pots and Pans (6)
Kitchenware including stainless steel knife set etc.
Set of cutlery for 8
Set of towels with name of boat embroidered

comfort

Nicro Fico solar vents 4 x
Strida folding bikes lightweight 2 x
3 sided outside cockpit enclosure with windows
Fitted cotton sheets for the beds 8 pieces 900 mm x 2200 mm
Comforters with covers for each bed
Pillows with pillow cases
Fitted cotton undersheets 4 x
Solar shades mounted on the outside of saloon
Outside matrasses 2 x 60 x 2.10 meters
Lexan scratch resistant, solarized,self cleaning windows
Lexan scratch resistant,portholes and hatches
Upgrade water tanks 700 litres total
Upgrade diesel tanks 600 litres total

Holders for 3 diving bottles

This is what we call ocean ready

Greetings

p.s. if you need any advice or help let me know

[fastcat435]

Hallo Alan

I noticed that you mentioned that with resin infusion you could only save 250 kilo,s
I do not know where you got your figure but do not forget if you go with hand lamination that the bonding past alone will be far over your estimated 250 kilo,
I do not want to be a wise guy but with having built close to 60 yachts to day I know what you can save with resin infusion.
Just take the resin to glass ratio with perfect hand lamination
If you achieve 30 % glass to 70 % resin you will do good
With resin infusing epoxy we get 62 % fiber to 38 % resin ratio and no bonding paste used.
We have saved well over 1800 kilo,s from going from hand lamination to epoxy resin infusion on our 44 ft cat
Our hull laminate now weights 4.9 kilo per squire meter and in the move to go to basalt fiber we will shave of another 250 grams x 400 squire meters = 100 kilo,s

Greetings

Gideon

[Nordic cat]

Originally Posted by fastcat435

Hallo Alan

we build our cats on electronic load scales and during that process we move weight around to get the boat as good as possible balanced.
The weight we actually measure our cats at are actual weights.
Including all equipment for ocean crossing including the following list

Sterling fast charger
Air Breeze wind generator masthead mounted 300 watt 24 volts
LCD TV screen connected to radar screen for large picture 26 inch
Dolby surround system multi system for world wide use
Multi region tv/fm antenna with mast bracket suitable for digital TV
Capi2 power distribution system
Active radar deflector detector
Raymarine GPS/plotter, radar 8" and 12 " color + interface to LCD screen
Watermaker 16 gallons per hour 24 volts manual
Victron 2000/100 inverter / charger .
Mobilert active overboard alarm system for 6 people type 7600
Davits aluminium with lines and blocks
Debug for engines or generator (against algae in diesel)
Autopilot self learning
Floscan digital fuel flow meter with total consumed diesel
1 x Solar panel 210 watt .

safety

Book Doctor on board

First Aid Kit (Extensive)
Outboard 2,3 hp 4 cycle
AIS system to monitor other shipping around
8 fenders 8 mooring lines 4 mooring lubbers
Lightweight rigid inflatable 10 ft long 4-5 persons
Safety outfit lifejackets safety harnesses life lines
Spare anchor (Rocna)15 kilos plus 10 meters chain and 50 meters line
Anchor bridle with stainless steel connecting plate
Life raft light weight for 6/8 pax
sails

Gennaker with lines and blocks 135 M2

Gennaker with lines and blocks 95 M2
removable bowprod with spectra waterstays 80 m2
Storm Jib with Velcro connection
Sea anchor/Drogue (for heavy winds)
kitchen

Side by side fridge freezer 200 L.

Freezer 50 gallons w. cooled in saloon seat
Extra gastank composite
Polycarbonate glasses 24 x
Nespresso coffee machine by Magimix
Dualit Toaster
Kitchen machine
Hardwood cutting board installed above dish rack
Light weight washing machine ( 3 K . )
Light weight set Dinnerware for 8
Nesting Pots and Pans (6)
Kitchenware including stainless steel knife set etc.
Set of cutlery for 8
Set of towels with name of boat embroidered
comfort

Nicro Fico solar vents 4 x

Strida folding bikes lightweight 2 x
3 sided outside cockpit enclosure with windows
Fitted cotton sheets for the beds 8 pieces 900 mm x 2200 mm
Comforters with covers for each bed
Pillows with pillow cases
Fitted cotton undersheets 4 x
Solar shades mounted on the outside of saloon
Outside matrasses 2 x 60 x 2.10 meters
Lexan scratch resistant, solarized,self cleaning windows
Lexan scratch resistant,portholes and hatches
Upgrade water tanks 700 litres total
Upgrade diesel tanks 600 litres total

Holders for 3 diving bottles

This is what we call ocean ready

Greetings

p.s. if you need any advice or help let me know

Hi,

The list is impressive!

So, let me understand this:

What will a boat weigh with the above equipment, and anything else needed for Category A status for 6 people?

Is that 4800 kgs?

[Nordic cat]

Originally Posted by fastcat435

Hallo Alan

I noticed that you mentioned that with resin infusion you could only save 250 kilo,s
I do not know where you got your figure but do not forget if you go with hand lamination that the bonding past alone will be far over your estimated 250 kilo,
I do not want to be a wise guy but with having built close to 60 yachts to day I know what you can save with resin infusion.
Just take the resin to glass ratio with perfect hand lamination
If you achieve 30 % glass to 70 % resin you will do good
With resin infusing epoxy we get 62 % fiber to 38 % resin ratio and no bonding paste used.
We have saved well over 1800 kilo,s from going from hand lamination to epoxy resin infusion on our 44 ft cat
Our hull laminate now weights 4.9 kilo per squire meter and in the move to go to basalt fiber we will shave of another 250 grams x 400 squire meters = 100 kilo,s

Greetings

Gideon

Hi Gideon,

The attentive reader will have noted that vacuum bagging is used. This can for certain foam types actually be lighter, and have a better resin/fibre ratio than infusion. In my case, bagging is heavier,
That is why I estimate 250 kgs heavier.

Regards

Alan

[Fard12]

At 7000kg L/Ship and a Hull cntr line beam of around 7.2 mtrs you will have a rm at 11deg of approx 21180kg m. You will have to have some deep pockets to afford the carbon masts for it.
Good luck.

[fastcat435]

Originally Posted by Nordic cat

Hi Gideon,

The attentive reader will have noted that vacuum bagging is used. This can for certain foam types actually be lighter, and have a better resin/fibre ratio than infusion. In my case, bagging is heavier,
That is why I estimate 250 kgs heavier.

Regards

Alan

Hallo Alan

I think you are being very optimistic with 250 kilo, being optimistic as a boat builder is good but a bit of realism also helps. It is my guess that your 47 ft cat will come out at around 8 tons ocean ready in hand lamination while if you go the whole way with epoxy and resin infusion the first saving would be around 2 tons.
Yes the list above is included in the 4800 kilo . the hard top bimini is not .
It has taken us a lot of shaving here and there to come to this 4800 kilo and we are still working to get her down to 4500 kilo
That is the ultimate aim for this 46 ft 9 inch cat
Proposed weigth for our new 58 ft cat is 9 tons ocean ready and 3600 kilo for the new 41 ft cat.
Again if I can help in any way let me know , I am just in this for the hobby I get get my kicks out of development.

Gideon

[Nordic cat]

Originally Posted by Fard12

At 7000kg L/Ship and a Hull cntr line beam of around 7.2 mtrs you will have a rm at 11deg of approx 21180kg m. You will have to have some deep pockets to afford the carbon masts for it.
Good luck.

Hello Fard12,

We haven't finalised the weight study, but with a hull centerline beam of 6.30 meters, and 6.5 tonns, the hydrostatics program gives me a figure of 3500 kg m for one degree. At around 5 degrees, the chines in the hulls will "come into play" and increase the righting moment even more, so your figure is probably a bit on the low side!

The masts will be engineered wth a safety factor of 3.5. Preliminary studies show that we will be using about 200 kg unidirectional carbon pr. mast, maybe a bit more. So I have purachased 500 kgs. This should cover the masts and booms, leaving a bit for deck reinforcement, otherwise its back to the shop for more....
I will save some weight and materials compared to a traditional rig, as the main beam can be a bit lighter, no forward beam, no stay attachments to be reinforced etc. At the end of the day, this rig (including the weight savings in the hulls) will be marginally heavier than a traditional aluminium rig, but with much lower wind resistance. Estimates show that at 20m/s wind the rig gives about 10% of the windage compared to a traditional rig that means around 100 N compared to 1000N. (Only if the masts are aligned to the wind!) Of the 1000N on a traditional rig, more than 25% comes from the rigging, the rest from the mast. But these are still, and will remain estimates, as hard data regarding wind resistance for masts is not readily available.

If anyone knows where I can get some - it will be appreciated.

Thanks

Alan

[Fard12]

The RM was a very rough estimate without taking into account hull form or VCG of the boat.
Good luck with your venture.

[Nordic cat]

Originally Posted by fastcat435

Hallo Alan

I think you are being very optimistic with 250 kilo, being optimistic as a boat builder is good but a bit of realism also helps. It is my guess that your 47 ft cat will come out at around 8 tons ocean ready in hand lamination while if you go the whole way with epoxy and resin infusion the first saving would be around 2 tons.
Yes the list above is included in the 4800 kilo . the hard top bimini is not .
It has taken us a lot of shaving here and there to come to this 4800 kilo and we are still working to get her down to 4500 kilo
That is the ultimate aim for this 46 ft 9 inch cat
Proposed weigth for our new 58 ft cat is 9 tons ocean ready and 3600 kilo for the new 41 ft cat.
Again if I can help in any way let me know , I am just in this for the hobby I get get my kicks out of development.

Gideon

My weight study, done in collaboration with a very experienced designer and a yard that builds more than 10 boats a year, using vacuum bagging,
(Gideon - please note for the third time now - VACUUM BAGGING) puts the hulls and deck structure at around 2500 kgs.
So in your infinite wisdom - you state that i can save 2 tons off this value

With vacuum bagging, they achieve better than 60/40 fibre/resin ratios, as they weigh all materials and parts. With infusion you can get maybe 5-10% better, depending on the foam, foam structure and the setup.

I understand and respect your endeavours to optimise your boat weight, and you have lots of great ideas, and try/test new ideas. Your willingness to share this with us is great.

Sometimes I get annoyed by some of your statements that I consider "half truths" - please tell the full story!

Like your statement that you can save further weight by using basalt fibres (I think it was). It is true that you can save weight by using lighter and stronger fibres. BUT, you also know that when building to CE/RCD standards, the requirements for the outside of the hulls is 1200 g/m2, with no possibility to work around this. So the weight saving will be ZERO!

If you are not building to RCD, then you could go down on your fibre weight, many of the Australian boats are built lighter, and save even more. say 400 g/m2 fibre and 1:3 ratio gives 533 g/m2.

There are lots of other things you can save on when not building to CE. Hatch weights, no toe rails, hoses, hull fittings etc.

My request is that when telling the upside, also remember to tell the whole story, so that we don't inadvertently mislead people. Good engineering is based on critical evaluation of the facts, not the hype.

Regards

Alan

[fastcat435]

Hallo Alan
The proof of the pudding is in the eating as the saying goes
We have worked with vacuum bagging and have gone from there to resin infusion because of the weigth saved and no air inclusions. Do yourself a favor if you build a female mould to save on later costs. Ad a flange all around of 300 mm and make sure the mould is completely airtight. That way you can always gom to infusion without much cost.If you want to pick my brain you are welcome to do so , you know my phone number . p.s. where did you read that a minimum of 1200 grams of glass is mandatory on the outside for CE approval ? I thought I had by now memorized all the rulings and regs on the CE approval but have not been able to find that.
Our hull now weigths 4.9 kilo per squire meter and that is the lowest we have been able to achieve. ( we are CE A approved )
Theory and practice should work out the same but in the real world they hardly ever do. you might be able to get to 60/40 % glass to resin ratio in theory but it does work out different in practice. This is only my experience , take it for what it is worth.


Greetings
Gideon

[multihullsailor6]

Originally Posted by Nordic cat

How do you tack by the way? Do you lock the leeward boom before going around, and thus let the now windward sail push you around?

Hi Alan,

Have now returned from my weekend of racing the Radical Bay 8000
- 70 miles feeder race on Friday (no wind to Bft2 beam reach)
- 25 miles double S-shaped bay race with lots of tacking, wind 15 - 40 kts on Saturday.

What I can now tell you about tacking this boat is

1) In wind under 20kts-ish just before commencing the tack release the windward sheet totally and tack on the leeward sail. Wait for the (new) windward sail to fill and push the bows around, then slowly sheet in the leeward sail and off you go. Only in really flat conditions would we play around with the daggerboards to assist the tacking effort.
Results 10/10

2) In wind in the 20-25-ish kts we have a problem! Depending on wave action we cannot tack and have to gybe.
Results 4/10

3) In winds of approx. 30kts and more we cannot tack nor gybe!!
When tackinh the boat would stall 10 degrees from the turn, even sailing backwards did not work to push the bows through the wind.
Attempting a gybe, the pressure on the rudders was incredible, could run down-wind but not turn further to the leeward side. Ended up anchoring in 40kts of wind on a lee shore! (Can really recommend the Fortress anchor!). And managed to break the mast / gooseneck boom connection due to a gybe which went wrong.

This weekend's experience has put a big damper on my otherwise positive aspects of this rig design!

Regards
Roger

[Nordic cat]

Originally Posted by multihullsailor6

Hi Alan,

Have now returned from my weekend of racing the Radical Bay 8000
- 70 miles feeder race on Friday (no wind to Bft2 beam reach)
- 25 miles double S-shaped bay race with lots of tacking, wind 15 - 40 kts on Saturday.

What I can now tell you about tacking this boat is

1) In wind under 20kts-ish just before commencing the tack release the windward sheet totally and tack on the leeward sail. Wait for the (new) windward sail to fill and push the bows around, then slowly sheet in the leeward sail and off you go. Only in really flat conditions would we play around with the daggerboards to assist the tacking effort.
Results 10/10

2) In wind in the 20-25-ish kts we have a problem! Depending on wave action we cannot tack and have to gybe.
Results 4/10

3) In winds of approx. 30kts and more we cannot tack nor gybe!!
When tackinh the boat would stall 10 degrees from the turn, even sailing backwards did not work to push the bows through the wind.
Attempting a gybe, the pressure on the rudders was incredible, could run down-wind but not turn further to the leeward side. Ended up anchoring in 40kts of wind on a lee shore! (Can really recommend the Fortress anchor!). And managed to break the mast / gooseneck boom connection due to a gybe which went wrong.

This weekend's experience has put a big damper on my otherwise positive aspects of this rig design!

Regards
Roger

Hi Roger,

Sure sounds like a bit of a problem in strong winds!

I used to have a much lighter cat, an Iroquois, that could be difficult to tack in waves, Ithink tha lack of inertia is the biggest problem with a very light boat.

What about reversing the helm when backing? that normally brings the bows around?

What about tightening the windward sheet, and loosening the leeward one, to increase weather helm. Then slowly tighten the (now) windward sheet to accelerate?

It could also be an issue that the centre of effort on the sails is too far aft, because normal cat-rigged boats have their masts even further forward, and don't seem to have these problems.

Sorry to hear about the damage.... good things no heads were in the way

Anyone out there have some ideas?

Regards

Alan

[BigCat]

" 3) In winds of approx. 30kts and more we cannot tack nor gybe!! When tackinh the boat would stall 10 degrees from the turn, even sailing backwards did not work to push the bows through the wind.
Attempting a gybe, the pressure on the rudders was incredible, could run down-wind but not turn further to the leeward side. Ended up anchoring in 40kts of wind on a lee shore! " That's frightening. I'd e-mail the designer immediately and ask for his comments. If you do, please post any reply he makes. I'd probably build bigger rudders. I can see how a very light boat might be unable to tack, but being unable to gybe is puzzling, to say the least. I would think the only effect the biplane rig would have on this is that you don't have a foresail to back to help you around, so it is like a cat or una rig in that regard. If your sail area is too far forward, you have problems tacking, and if it's too far aft, you have problems gybing. A problem doing both doesn't sound like a rig balance problem.

[David M]

Originally Posted by fastcat435

Hallo Alan

I think you are being very optimistic with 250 kilo, being optimistic as a boat builder is good but a bit of realism also helps. It is my guess that your 47 ft cat will come out at around 8 tons ocean ready in hand lamination while if you go the whole way with epoxy and resin infusion the first saving would be around 2 tons.
Yes the list above is included in the 4800 kilo . the hard top bimini is not .
It has taken us a lot of shaving here and there to come to this 4800 kilo and we are still working to get her down to 4500 kilo
That is the ultimate aim for this 46 ft 9 inch cat
Proposed weigth for our new 58 ft cat is 9 tons ocean ready and 3600 kilo for the new 41 ft cat.
Again if I can help in any way let me know , I am just in this for the hobby I get get my kicks out of development.

Gideon

Gideon,
Is that correct...9 tons for the 58 foot hull alone or 9 tons in a ready to sail condition with all the amenities you mentioned? Do you mean short tons at 2000 pounds or do you mean long tons at 2240 pounds (1000kg)? In my business we use both.

Perhaps keep it simple, at least for me please, and use kilograms? I know us Yanks are still in the dark ages using pounds, feet and short tons. Don't worry, there are plenty of conversion websites for us.

One of your competitors in South Africa has a 48 foot boat with a light displacement at 8000kg and a 66 footer with a light displacement at 15,400kg. What will be the light displacement of your 58 footer in ready to cruise condition in kilograms?

I think your boat is going to hit a sweet spot in between those two lengths.

David

[multihullsailor6]

Originally Posted by Nordic cat

What about reversing the helm when backing? that normally brings the bows around?

What about tightening the windward sheet, and loosening the leeward one, to increase weather helm. Then slowly tighten the (now) windward sheet to accelerate?

It could also be an issue that the centre of effort on the sails is too far aft, because normal cat-rigged boats have their masts even further forward, and don't seem to have these problems.

Hi Alan,

Tried the sailing-backward technique, she still fell off to leeward!

Besides enlarging the rudder surfaces, we are also considering a centre front canard rudder to help push the bow around, though haven't gone into any design details yet.

Sailing a new design concept surely is interesting!

Roger