89er

[JulianB]

Re the B2B, let you guys reminisce about that. Tall tales of the bold and beautiful.

Just a wake up call, the boat is in my front yard undergoing a over haul. One of the things I have overhauled in the spinnaker pole. Replaced the haul out line which is 4mm SK78 Spectra. Max load likely to be 2 guys hauling 2:1, so 150-200kgs maybe a tad more.

I had been settling my new shrouds, took them to 1.2 -> 1.3 tonne no issue, so because I had it there and wanted to settle the haul out line, I put it on the chain-block, assuming I could go easily to 1.2-1.3 (BS is 1.5) At about 0.78 rather big bang.

The culprit would appear to be the coarseness of the taper.
I tend to do a 50:1 bury and a 20:1 taper (as part of that bury)
So M4 x 50 = 200 & M4 x 20 = 80.
The total bury is 200mm, but the last 80mm is tapered

Did another haul out line, same roll of rope, same bury, same everything but just a bit more anal on the rate of taper and the "correctness" of the taper, put it back on the chain-block and pull well over a tonne.

Can't say I was overly observant, I was lucky the first time, so I was "timid" but do it well, or don't do it!

 

[PUNISHER]

Hi neuronz, firstly can't say I agree with you above comment, I have never had a VPP give an exact number, in-fact, most VPP have so much fudge factor built in, they can only be called a in-exact science, but I get where you are coming from.

To that effect, Rob (Sidecar) has a mate Rick who has done a whole Java Foil predict program for which I an exceedingly grateful.

Again, absolutely love this stuff and the insight that comes from others taking a slightly differently slant on the same problem. Rick did that, introduced AR to the equation, and modeled the actual section and also added some thoughts on his POV and possible tweaks.

Both of us believe that the really big advantage comes from negating Yaw Drag.
The 2nd highly probably significant advantage will come form a reduction in the size if the fin due to a substantially increase in CoL. (almost double)
3rd is what we already spoke of, being a increase of AoA on all the sails off approx 2-3°, so this is the jib-sheeting angle, but also carries across to the main. Spinnaker down wind, interesting possibilities, the boat will crab to windward, so do you zero the TE or do you simply pull-away another 2-3-4° lower.

Time will tell.

4th that I had not thought about is you can dramatically sharpen the LE of your fin, lowering induced drag. That's a new bit of understanding. May be building a few fins, but this is what this boat is all about.

Certainly Rick has given me a lot of confidence to reduce foil length by at-least 200mm. I'm very sure Punisher will even be more happy as if he can cut 300mm off, where he sails (mouth of the Murray River) he won't have an issue, won't have to lift at all. Need to start on Rudder length, that may become the issue.

Next step, capsize test with 74kgs bulb weight, I can hang a bucket with 10kgs on the bulb if it marginal, or 2 buckets, we will get real empirical info I'm sure that Tubby and Brian (Punisher) will be ecstatic for.

Happy to share this with all of you, inc the video, so there are no innuendo's!

Great few days, Rick, plus we won (Wednesday beer can race) last night, really relaxed plesant sail and got fastest time over all the boats by 3+mins. Really good day at the office.

 

[JulianB]

12/04/2023​

Just did the ISO stability test on DP.

We set the board 320mm up, so draft would be approx. 1500mm below WL, (instead of 1820mm) used the 136kgs bulb.

Pumped bit over 500kgs of water into the bilge, sealed it all off. And then with a 2:1 through the main halyard, pulled the boat over horizontal.

It took well over 15kgs, probably close to 20kgs to hold the mast tip under water for over 1 min.

Then we let it go in a controlled manner, (few reasons for that inc not wanting to lose the main halyard) and it came straight back up, very positively.

We passed easily; very likely we will also pass with a 75kg bulb on a shortened fin.

All this was overseen by John Sturrock with a few phone calls to John Swarbrick to make sure we did it the right way.

That (75kg bulb) will now be a high order of priority, getting the bulb up and going, then test it on the existing fin, may lift the fin 400 and 500mm and see if it still will satisfy the test (think it will do it easily) and then we can start on the flexible TE fin, possibly have that all ready for Airlie.

Ofcourse we will have to do that same ISO Stability test again if we use the 75kgs bulb, regarless of fin length, prior to ABRW and we will have to get our Cat 5 re-verified (all certs expire June 30th in Australia) plus I guess we may need to re-apply for the CBH, maybe without the #1 jib. All doable!

Good day at the office, there is a video, it’s un-remarkable, but it exists.

But B2B, we are all “good to go”! Leave in 10 days to Port Stephens and then in 2 weeks for Brisy!

John Sturrock and his daughter overseeing the process. Plus the 50L plastic tub which we used to time how long it took to get 50kgs of water.

Boat coming back up, GT doing the spreadeagled thing!

Boat over horizontal. snips taken from the video

Boat just prior to the test, Main on boom, outboard in place, rudder on, you can see the fin up.

We had one of the Ozito 240v bilge pumps, (you can see the hose and power cord near the bow, it's in the water), even still it took 13+ mins with it pumping the water into the hull (to simulate crew weight) and took that again to pump it out plus the onboard bilge pump. We worked out how much time was needed by timing the same pump filling a 50L plastic container and then x 10 to get 500kgs, in reality we probably had 520-530kgs because we had a lower head, pumping into the boat, but it matters not, it passed so easily.

Just got to write it up, get the John (Sturrock) to sign it off and then send it to the other John (Swarbrick who is a NA) to file it.

 

[chris foiler]

I’m positively impressed with your stability and reduced need for keel bulb weight

 

[JulianB]

I’m positively impressed with your stability and reduced need for keel bulb weight

I'm not so surprised
The winglets are almost 0.5m³ volume, and sure they have limber holes in them but they are 3 x M8 drain holes and 1 x M8 breather so it will take a while for them to fill.
Plus the area fwd, the opening in the main load bulkhead is design to be well above WL more so, it's the minimum opening to allow reasonable access which is more about managing the rig load than a potential capsize, so there is a lot of buoyancy up hi. The boat floated very nose down (as expected) when on it's side, back of the winglets where out of the water, so a really hi CoB on it's side which added to the effective arm for the bulb. Plus a lot of attention to weight aloft, Dynema shrouds, drop rigging weight by far more than 1/2, acetyl mast head fitting, etc etc.

Anyway, it's done, and it passes easily, so playing around with 75kg bulb now and see how high we can lift the fin, which will give as great empirical data re Flex TE/span length.

I'm sure Sidecar is salivating!

Week Saturday I drive to Port Stephens, and do the Farr 40, initially Newcastle to PS then for 4 days in PS before driving on Thursday to Brisy and then Sat Sun (29th - 30th) doing the B2B.

So plenty on in not much time!

jB

 

[Sidecar]

I'm sure Sidecar is salivating!

Will be interested to see what you end up doing………

Especially the TE details.

 

[Sidecar]

I’m positively impressed with your stability and reduced need for keel bulb weight

Just remember that DP is really a big dinghy, with 6 crew hanging off the gunwhales for RM. The bulb weight is there to only to pass the ISO test and to stop it from falling over when it is tied up to a mooring or pontoon.

The carefully designed highly flared bolt on side tanks give a big buoyancy shift to leeward which helps as well, both for sailing RM and for the capsized righting test.

 

[sheeting yarns]

the only downside will be that if the boat were to capsize and the crew washed off, it could more easily turn 180 degrees and be more difficult to right because of the volume in the sides.

 

[he b gb]

the only downside will be that if the boat were to capsize and the crew washed off, it could more easily turn 180 degrees and be more difficult to right because of the volume in the sides.

Good point, especially with the windage of the hull floating high on its gunnel when knocked down.
Never going to happen in the B2B though!

 

[DickDastardly]

The winglets are almost 0.5m³ volume, and sure they have limber holes in them but they are 3 x M8 drain holes and 1 x M8 breather so it will take a while for them to fill.

So with removable plugs in the drain holes and breather you could make it unsinkable, yeah?

 

[Sidecar]

the only downside will be that if the boat were to capsize and the crew washed off, it could more easily turn 180 degrees and be more difficult to right because of the volume in the sides.

Not likely to happen with a good crew….. at least a couple of them should be able to swing over and get on the keel in time.

I got blown flat upwind once in the UK on a J24, there came a point when you knew that the boat wasn’t going to come back and instinctively headed for the keel. I’ve done it…..life lines and all and I was on the helm at the time.

The boat did come back with two of us on the keel, we didn’t lose anyone, and carried on and finished the race.

But if it ever got to turtle, there is nothing to grip or stand on near the gunwhale to initiate a roll back.

 

[sheeting yarns]

Not likely to happen with a good crew….. at least a couple of them should be able to swing over and get on the keel in time.

I got blown flat upwind once in the UK on a J24, there came a point when you knew that the boat wasn’t going to come back and instinctively headed for the keel. I’ve done it…..life lines and all and I was on the helm at the time.

The boat did come back with two of us on the keel, we didn’t lose anyone, and carried on and finished the race.

But if it ever got to turtle, there is nothing to grip or stand on near the gunwhale to initiate a roll back.

yes, agree. The boat is fantastic and potentially would make for great class racing but probably not ideal for inexperienced sailors thinking they can get their thrills with limited knowledge and experience.

 

[Sidecar]

yes, agree. The boat is fantastic and potentially would make for great class racing but probably not ideal for inexperienced sailors thinking they can get their thrills with limited knowledge and experience.

You could say that about most sports boats. I like to think that I have more than limited knowledge and experience and I have been on a capsized J24 twice and thrown out of a Melges 24 once….

In the case of the Melges, I was on the mainsheet and was thrown out during a sudden violent broach with the kite up doing 19 knots. Still had the mainsheet in hand, pulled myself back on board, over the open transom (very handy they are) and still went on to win the race…..

 

[Sidecar]

So with removable plugs in the drain holes and breather you could make it unsinkable, yeah?

Maybe that is why Julian has fill and vent holes. In the unlikely case of going turtle, the winglets can flood to assist roll over?

 

[Schnick]

Without breather holes you would very quickly have a very sinkable boat....

 

[Sidecar]

^^^ My guess is that between the foam sandwich construction and the false floor void, the 89’er is pretty unsinkable regardless of flooded winglets.

 

[JulianB]

Opened a can of worms,

DP hull is mostly 25mm of PET foam core, the rest is 14mm PET foam core.

13-14m² of 25mm core so there is 350kgs of buoyancy there.
Another 35m² in topside, deck cockpit floor, yad yad yad
So another 500kgs of buoyancy there, then add internal frames, EVA foam and all those fillets and sundry bits and pieces, so if you compromise all 5 "flotation tanks" it still aint going to sink with the 5-6 crew sitting on the boat.

But your comments re boat right up-side down is relevant and GT and I have been contemplating that. Our thinking is if you have a plan and made some provisions for it, then it will never happen. If you stick your head in the sand, then when it happens and it will, you "not flash!"

It's not going to happen during the B2B because it too shallow.

But our current think is, especially given the stability test is to make 2 drainage holes (25-30mm dia) in the "transoms" of the winglets, so one would be low right at the back (more of a key-way shape) and the other as far out and aft as we dare. Also there are already 3 x M8 drainage hole at the lowest point (about 2m fwd, inside the Hull/Winglet joint and another 1 x M8 breather hole directly above those. We did not seal these during the test, and yes there was some water in the downside winglet on righting, not a lot but a bit.

The thinking being that if we did go completely upside down, then bit of weight on the wing, the far out 30mm dia hole will end up under water and we can then flood a winglet. We could cover them with sticky back so they could be ripped off if needed. Need to give it some more thought!

Re the ISO test, there is a bit of paper, which needs to be filled in, we did everything but put the jib lashed to the deck, we did not do that because on asking we where told it was irrelevant. Plus we only needed to put 450kgs of water in (for 6 people (75kgs/person)) so well and truly over cooked there, I think that was it.

Anyway, I know it comes back up easily, and that's documented, so if challenged I'm happy to be tested there and then which is what it's all about. (obviously you counter protest, "whats good for the Goose is good for the Gander", so whomever chalanges has to do it also)

When we do the 75kg bulb, we will probably be more anal about the detail, even if 90% of the fleet dose not care and has not done it.

I'm more about having fun and knowing myself that it's a safe toy to go push hard, remember, all of the people sailing this boat are mates, last thing I want to do is hurt anyone, but if shit happens, we have a plan!

 

[Will1073]

The boat looks really impressive at the dock. Thanks for bringing us along JB!

 

[PUNISHER]

great job JB and GT. watching with baited breath on the TE advancements, still keen on one for my sports 8, we pick it up thursday and stand mast on friday!!

 

[JulianB]

Saturday was fun, Friday night was funner, Jen Morgan-Glass and Ben Glass had Deidre, Harry and I over for dinner, quite a few bottles of red latter and a Uber home, Jen was coming sailing with us the next day, Jen is a "All-America sailor", used to be the pres of the I29ercA and the I29erXXCA, also not a slouch on the FX or a Tasar, hails from Seattle, went to school in Dartmouth (Engineer), and Ben was her coach, Ben now dose AC stuff (RM plus Drones and all sort of other stuff (also a Engineer)), they are heading back home after a 3 year stint here, anyway, Jen complained about not enough sailing and I was shy a crew for the next day, one thing lead to another, Jen ended up making a guest appearance as a "visiting skipper".
Noddy (Andrew Hay) and Jimmy Beck, possibly 2 of the best 18teen fwd hands ever were a tad skeptical, a American steering DP (a big skiff), anyway, Jen showed them how it was done, really great day sailing, the 3 of them plus GT, Alex (B) and me, 8-12 knts, played around with Code Zero, got a whole bunch of systems working really well and I got my mainhead winglet on and working.

Decided to go really small and see what happened. This thing is probably 250mm f-a and CL to tip 100mm, (there is another out the other side) I got some Vee-blocks made (3D printed) that hold them all at 120°.

The immediate reaction from Jimmy and GT (who are normally sheet-hands and looking up there all the time) was that the tuff you can see stopped doing spirals. Both of them where adamant that there were less spirals (as in none) and they could sheet in the upper main further and more attached flow, especially down-wind under kite.
We will use it in the B2B, but may take some time to get anything conclusive. (I was unaware there were spirals before)
But it looks pretty cool, wins the Gucci test, hands down! Bright orange helps!

Jen and me on the way back in. Great day.

Boat is now packed up, ready for 1/4 of the trip to Port Stephens on Saturday then all the way to Brisbane Thursday week, B2B, in 12 days time.

Had a great chat with John Sturrock this morning, he signed my report on the stability test!

He and Kirsty want to come for a sail, and the plan is to do that mid May, when the boats back and we do the 75kg test, with all the bells and whistles.

Just putting this in the public domain, so people know we did it, and the result.
It will now work it's way through the machinations of AS and ASBA.

Brian, (Punish-er), planing your lead, today I also cast the talon into the 136kg bulb, so I can duplicate it with the 75kg bulb.

As commented above, hope to re-do the ISO test mid May, with 75kg buld at say a 1.1m effective fin length. I hope to exercise Rod (Sidecar) and Rick mental capacities some more as I work my way through all of this, I am sure I can come down shorter, but I know when you lift a 49er foil say 400mm, it handles completely differently, sure, lot faster, but very skiddish.

I can still picture, I was in the sth of France (Bandol/Sanary) and "the Earl of Ruttland" (Tim Robinson) was coming home in a 49er, it was pre 2000, I was in a chopper, we had been filming for the European 49er GP, which in those days was huge. He had pulled his foil up 500+mm. It only goes into the water 1.1 fully down, but 2 sail reaching, over the tops of these big "Mistral" generated swells, absolutely smoking. Others started to copy him, and before long you had 30-40-50 49ers launching of waves at quite extraordinary speeds. Latter they all commented on how weird the boat felt and if anyone could master that, they could! Non now do it in a race, so I am cautious of getting to far away from what is know to be fast!