LATEST BI-PLANE CAT - THAILAND

[RadSamui 0]

So we stepped one of the CF masts yesterday to size up the rigging etc. Sails and tramp material will be dropped off in Phuket tomorrow for reefing cringles (sails) and assembly (tramps). Still waiting on the rudder pintles and gudgeons to arrive from US - over 2 weeks since we placed the order now and still nothing handed over to Fedex

 

Gonna miss the Phang Nga Bay Regatta but gives us more time to get her tuned.

 

[Steveromagnino 2]

So we stepped one of the CF masts yesterday to size up the rigging etc. Sails and tramp material will be dropped off in Phuket tomorrow for reefing cringles (sails) and assembly (tramps). Still waiting on the rudder pintles and gudgeons to arrive from US - over 2 weeks since we placed the order now and still nothing handed over to Fedex

 

Gonna miss the Phang Nga Bay Regatta but gives us more time to get her tuned.

 

 

 

SWEET.

 

I think eventually one of these boats will get really sorted, and clean up some regattas if they can get the downwind part sorted.

 

Is this the same as storm, or different again?

 

There is a good race in Pattaya; the Top of the Gulf Regatta....I think you guys need to come up and do that one to tune up for Samui and a round the island attempt ;_)

[richie 0]

Looking good...hopefully you can make it go faster than "Storm" .Can't wait,where the WL will be...those steps looks awfully "draggy",but if the boat is lite enough,one could have some fun...good luck!

[Michael Grover 0]

So we stepped one of the CF masts yesterday to size up the rigging etc. Sails and tramp material will be dropped off in Phuket tomorrow for reefing cringles (sails) and assembly (tramps). Still waiting on the rudder pintles and gudgeons to arrive from US - over 2 weeks since we placed the order now and still nothing handed over to Fedex

 

Gonna miss the Phang Nga Bay Regatta but gives us more time to get her tuned.

 

 

 

SWEET.

 

I think eventually one of these boats will get really sorted, and clean up some regattas if they can get the downwind part sorted.

 

Is this the same as storm, or different again?

 

There is a good race in Pattaya; the Top of the Gulf Regatta....I think you guys need to come up and do that one to tune up for Samui and a round the island attempt ;_)

Intending to do all of the above....look at the rig... 2X C.F Shaw 650 rigs.....

[RadSamui 0]

Looking good...hopefully you can make it go faster than "Storm" .Can't wait,where the WL will be...those steps looks awfully "draggy",but if the boat is lite enough,one could have some fun...good luck!

Design WL below the chine steps, should draw around 200mm with boards up - looking like she might clock in around 800kg. Below the chines she has a moderate 'V' decreasing aft with a flat pad that starts around 1/3rd from bow and gets wider aft. Bi-plane strengths are in sailing flat so general theory was that we designed hulls to suit the BP set up i.e. for flat sailing as in 'not' flying a hull. Guess we'll find out soon enough whether it works??

[RadSamui 0]

SWEET.

 

I think eventually one of these boats will get really sorted, and clean up some regattas if they can get the downwind part sorted.

 

Is this the same as storm, or different again?

 

There is a good race in Pattaya; the Top of the Gulf Regatta....I think you guys need to come up and do that one to tune up for Samui and a round the island attempt ;_)

Different to Storm which was pretty much based on the TC plans we bought for the 750. This boat is quite different below the water with a flat chine increasing aft. Also, as you know, she's got standing rigging so we WILL be flying a 50m2 screecher a la Shaw 650.

 

Yep, as Mick says we are planning to do TOGR as well as the proposed / possible multihull event that Henry is talking about just prior. Storm will be heading up as well as possibly 1 or 2 more from Samui (?? TBC).

 

RTI might just be on our immediate practice schedule once we get the sail set up sorted - Feb is usually a good month for breeze here, although the current El Nino conditions are a bit strange and very very hot.

[freedom 305]

Thanks for sharing the project --it looks great .

 

I,ve built a couple smaller {20ft } cats and attempted planning hulls but never got it right --still trying though .

 

It is somewhat a design goal contradiction in trying to reduce drag by planning but not taking advantage of lifting one hull clear of the water --which is where a jump in speed occurs on regular cat designs .

 

It should be very fast downwind with a kite up .--Have fun and thanks again .

[wwj5555 0]

She looks really great.

 

Can you provide a link to the builder's website?

 

Who is building the carbon masts?

 

I've seriously considered having a cat built for me in Phuket.

 

Good sailing,

[THOR 39]

She looks really great.

 

Can you provide a link to the builder's website?

 

Who is building the carbon masts?

 

I've seriously considered having a cat built for me in Phuket.

 

Good sailing,

I think you are talking to the builder here

and the rig is from a Shaw 650 well I guess two of them

[Amati 1,523]

How do the height of the masts compare with your ideal height of a sloop (or una) rig for the same type of cat?

 

Been reading too much Munk......

 

 

Paul

[RadSamui 0]

She looks really great.

 

Can you provide a link to the builder's website?

 

Who is building the carbon masts?

 

I've seriously considered having a cat built for me in Phuket.

 

Good sailing,

I think you are talking to the builder here - CORRECT (Link to web site at bottom of opening post or below)

 

and the rig is from a Shaw 650 well I guess two of them - CORRECT AGAIN - rig(s) an adaptation of the Shaw 650 and supplied by C-Tech in NZ - great work at a very good price. Sails also Shaw 650 from Lyttelton Sails in NZ, mains each around 19m2 and screecher 50m2.

[RadSamui 0]

Thanks for sharing the project --it looks great .

 

I,ve built a couple smaller {20ft } cats and attempted planning hulls but never got it right --still trying though .

 

It is somewhat a design goal contradiction in trying to reduce drag by planning but not taking advantage of lifting one hull clear of the water --which is where a jump in speed occurs on regular cat designs .

 

It should be very fast downwind with a kite up .--Have fun and thanks again .

Based on our experience on sailing the Radical Bay 8000's we built and raced we know that pretty much the boat sails flat with this rig. When a gust hits the boat just accelerates as opposed to heeling. On the RB's our calcs (and confirmed by one of the mast makers) estimated that with full sails up it would take 28knots of wind to approach flying a hull. Strongest sustained we sailed in was around 22-23+ and she was still flat and never felt like she was close to lifting. So our idea was that if the attitude of this rig set up is to sail flat then design the hull form around flat = planing. On the other hand Arnie over in Phuket has gone with foils on his bi-plane cat to 'induce' flying a hull and therefore reduce drag. We're trying the opposite and hoping to generate lift off the planing pads and reduce drag that route.

 

Yes, off the wind with a kite is looking like it could be fun and fast - the main reason we switched from free standing to stayed on the BP set up this time around.

 

I guess we'll find out soon enough if the theory works.

[RadSamui 0]

How do the height of the masts compare with your ideal height of a sloop (or una) rig for the same type of cat?

 

Been reading too much Munk......

 

 

Paul

The plans we got from Tim Clissold were specced for either a Bi-Plane or single mast set up. BP mast height; 9.0mt. Single mast height; 10.5mt. The actual C-Tech masts as fitted on the current boat are just over 8.7mt.

[GnTx 0]

What's the deal on rating - There was considerable discussion post the advent of the RBs and then Arnie also entered the fray with Happy Feet. Has this issue now been resolved and, if so, what percentage does OMR use for the second rig. Also, how does OMR factor in the screecher?

 

How do you set the screecher? From the leeward mast to the windward bow? Does that have any significance regarding downwind performance when compared to a normal single masted boat flying assymetrics?

[Steveromagnino 2]

What's the deal on rating - There was considerable discussion post the advent of the RBs and then Arnie also entered the fray with Happy Feet. Has this issue now been resolved and, if so, what percentage does OMR use for the second rig. Also, how does OMR factor in the screecher?

 

How do you set the screecher? From the leeward mast to the windward bow? Does that have any significance regarding downwind performance when compared to a normal single masted boat flying assymetrics?

 

It has gone back and forth AFAIK; initially they were valued a few years back at 55% for the 2nd main, which was considered to be a bit generous, and that was the year that Kings Cup was windy and one of the biplane boats flew around the course, prompting a few people to complain regarding ratings.

 

Then it went up to 75% I think, which now seems a little high.

 

I am sure that there are certain points of sail that the biplane rig works, but most importantly, the boat needs to be very very light to make it work from what I've seen; you are sailing on apparent, so the lighter the better; the radical bays already in the water are relatively more heavy as they were built to charter/sail for fun not just race; by dropping weight out and going with lighter rigs, I suspect the next iteration may be on the money, provided they are durable.

 

Can't wait to see. Also looking forward to seeing the ST7 which i think is a nice little machine; the i550 I am not convinced can handle the short seas we get here in Thailand (due to the warm water, I believe that this is why the wave structure tends to be realtively small but very steep chop) but i could be wrong.

 

BTW Builder is this group here; I've visited their factory a few times; a lot of expertise in multihulls, with a number of big cats under construction/delivered - beautiful location at Donsak near the ferry terminal to go to Koh Samui - easy enough to visit if doing KSR.

http://www.yachtingsiam.com/

[GnTx 0]

My guess is that carrying a spinnaker, the 75% allowance for the second main should increase as they will be effective sailing upwind whilst the spinnaker/screecher will be used downwind. Does anyone know whether there was a change in the allowance in the King's Cup for Happy Feet?

[Trevor B 76]

On the RB's our calcs (and confirmed by one of the mast makers) estimated that with full sails up it would take 28knots of wind to approach flying a hull. Strongest sustained we sailed in was around 22-23+ and she was still flat and never felt like she was close to lifting.

 

Sounds like you need a MUCH bigger sailplan to be in the hunt in lighter air.

 

I'd guess the planning hulls will be better when it's windy (when you're OK now,) and worse in the light stuff (where you suck now,) and that may not be what you're looking for.

 

Good luck, I think Bi-plane rigs are very cool.

[RadSamui 0]

On the RB's our calcs (and confirmed by one of the mast makers) estimated that with full sails up it would take 28knots of wind to approach flying a hull. Strongest sustained we sailed in was around 22-23+ and she was still flat and never felt like she was close to lifting.

 

Sounds like you need a MUCH bigger sailplan to be in the hunt in lighter air.

 

I'd guess the planning hulls will be better when it's windy (when you're OK now,) and worse in the light stuff (where you suck now,) and that may not be what you're looking for.

 

Good luck, I think Bi-plane rigs are very cool.

Tom Speer's comments on the B-P rig mention that he thinks the aspect ratio still needs to be around the same as for a uni rig. But bearing in mind that a higher aspect ratio raises the height of the heeling arm then we again start to approach the 'flying a hull changes the underwater shape' aspects. So at the end of the day it's always going to be a compromise between light wind (predominant in this region) and higher wind sail sizing and aspect ratio. Also a balancing act on the power to weight ratio vs. the heeling moment. Lot's of testing time on the water will be far more enlightening than the 'theory'. Looking forward to it. Rudder fittings have arrived at last and tramp and standing rigging should be sorted soon, so hopefully not too far away now

[RadSamui 0]

My guess is that carrying a spinnaker, the 75% allowance for the second main should increase as they will be effective sailing upwind whilst the spinnaker/screecher will be used downwind. Does anyone know whether there was a change in the allowance in the King's Cup for Happy Feet?

Happy Feet OMR TCF increased from 0.939 (no kite) to 0.992 at PKC for inclusion of kite (53 secs in 1,000) - doesn't seem like a huge change, but have not seen the rating sheet yet. Mark P is over at our yard next week - I'll try to get a copy for comparison.

[shane beyer 5]

My guess is that carrying a spinnaker, the 75% allowance for the second main should increase as they will be effective sailing upwind whilst the spinnaker/screecher will be used downwind. Does anyone know whether there was a change in the allowance in the King's Cup for Happy Feet?

Happy Feet OMR TCF increased from 0.939 (no kite) to 0.992 at PKC for inclusion of kite (53 secs in 1,000) - doesn't seem like a huge change, but have not seen the rating sheet yet. Mark P is over at our yard next week - I'll try to get a copy for comparison.

 

 

.992 thats pretty high ,how does it go against the fire flies or any thing else omr rated please let us know thank