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PostPosted: Mon Aug 08, 2011 4:06 pm 
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Could you please explain the use of the nylon safety lines and how they prevent the akas from dislodging, presumably from after a pin breaks.

Thanks for your help and suggestions.


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PostPosted: Mon Aug 08, 2011 6:25 pm 
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Location: Vancouver Island, Canada
Bob
I'm very impressed. Great job.
I'm gonna assume your warranty is no longer valid, hehehe.

Be well, eh?
Fred

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PostPosted: Tue Aug 09, 2011 6:10 am 
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Location: Sarasota,Key West FL
rhyolken :
If you look at the picture in the center of the first page it shows the safety rope. The reason I added it is twofold, first I got tired of the AMA's flopping around when in rough water, the bungie cords that hold the AMA's on work but they tend to flop up and down when underway (noisy).
The main reason though is the safety rope prevents the AMA's from folding in unexpectedly when in rough water (which would be a disaster, and the boat would for sure turtle if it happened).
What I do is run a 1/4 inch nylon (stretchy) rope from the center steel eyeletts on the AMA's around the front of the front AKA hull mount, then in the center behind the AKA mount, then again over the front brace on the other side (no need to tie it to anything on the hull itself), then finally to the other AMA. The rope doesn't need to be too tight, but if there is too much play it doesn't prevent the AMA's from rattling. I made a piece of rope with stainless D clips on each end that I just clip on while rigging the boat (only take a couple seconds to clip on) What this does in the event of a pin failure in the AKA brace is prevent the AMA from folding in until you can get your sails down and make repairs to the brace (an easy repair), then get underway again. On calm days I just leave it in the sail bag. To be honest I have never broken an AKA brace while underway, but have broken several bumping into docks.
My thought is that has to be alot of force on the AMA brace when your clipping along and a gust comes up and buries your AMA until you can release the sail a little, so I call it a safety thing. This mod makes no changes to the function or operation of the boat itself or it's design, it's just an insurance policy. I've been caught out in really rough conditions a couple times (not on purpose) with 30-35 mph winds and 3-4 ft waves where the conditions could easily break the AKA brace with disasterous effects. Hope this helps.

Bob


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PostPosted: Tue Aug 09, 2011 3:12 pm 
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Location: Sarasota,Key West FL
Fred:
Pretty much all the mods on this thread I did over a year ago when I first got my TI (I think my TI was one of the first in this area and was an early design). I have sailed just as is for over a year now with no major problems (probably over 1000 miles). Everything works flawlessly, and have made no additional changes since then (except the scupper cart thing in another thread). I'm out every weekend on some new adventure, we split our time between the Tampa bay area and Key West all year round. The boat is pretty much rigged for the light winds that are typical in the area (5-8 mph), the main purpose of the 265 sq ft of sail area is light air performance. I tend to reef the sails and go home when it gets too windy (boats not really designed for it). My purpose is to get where I want go, mostly scuba sites and Island hopping in light winds (typical around here). I got tired of going 1-2 mph in light winds with just the mainsail, so I added more sails, but was very careful to engineer everything properly so as never to exceed the design intent of the boat.

I feel the performance of my TI is similar to a WETA, or a Windrider 17 both of which are very nice and well made boats, but way more expensive and much less versatile (your not going to run river rapids in Colorado or Michigan with a Windrider, or snake up a narrow river, or go through mangrove tunnels in a WETA or a Getaway for that matter). Plus with the new rudder design I sail in 6 inches of water all the time around here (alot of shoals and sand bars) without skipping a beat, you just unlock the rudder down line and let it and the centerboard drag on the bottom till you get back in deeper water ( I know of no other boat that can even do that).
Plus I have to car top my TI, I don't think either of those boats could be car topped as I have no option to be able to have a trailer of any kind because of neighborhood restrictions at both Sarasota and Key West homes. The only other option would be no boat for me.

I believe the WETA's are around $13k and the Windrider 17's are around $10k. My total investment to date is.
TI ( I think was around $4600 when I bought it in I think April 2010)
2 hp kicker motor $525
Materials for sails and all modifications $400
Trampoline option $375
Total investment to date $5900
fun factor priceless
We have had several Hobies since 2007 so I already had the roof racks, kayak carts, dry bags, PFC's, anchors, coolers, tents, etc
I'm a pretty happy camper and really enjoy the Hobie way (there really is something to it).
Bob


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PostPosted: Sat Oct 01, 2011 8:13 pm 
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Location: Sarasota,Key West FL
Update Oct 2011:
Since doing all the mods a yr and a half ago, I've been just using the boat as is every weekend. I finally got tired of keeping the Assemetric Spinnaker (Gennaker) in a turtle bag and hauling up to the halyard everytime I wanted to use it, result was I hardly ever used it. I set out to design a roto furling gennaker (never see one before so I winged it). I first had to design and build a 2 ft bow sprit which further re-enforces the bow (the main sail on the TI is so far forward on the hull it's difficult to add more sail area) The bow sprit is a composite pulltrusion about 3/4 dia It is extremely light and strong, you can put the ends on two bricks and a 250 lb guy can jump on the center and it doesn't bend so I figure it's strong enough, plus it's just been laying around the garage for ten yrs.
This is the bow sprit
Image
The bow sprit is attached to the front AKA cross bar and fixed to the front with strapping and spectra line (not attached to the lift cleat)
Here is a pic of the boat ready to launch still on the car Image
Here is the boat ready to launch with all sails furled Image

Here is the gennaker unfurled Image
Here is the jib unfurled Image

All is controlled from 5 Harken cleats on the front AKA Image

Took the maiden voyage today and everything works perfectly, I can even furl the spinnaker in 15 mph winds (wasn't sure before trying it). Partially furled It acts like a huge genoa so I can deploy it now in wind from 70 to 290 degrees and it still works (used to be 90 to 270)

Here is a pic of my motor, the mote marine research bag over the motor keeps the green purists from speaking up (LOL) Image

Enjoy

Bob


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PostPosted: Sun Oct 02, 2011 1:52 am 
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Location: Central Coast NSW Australia
Wow Bob! :shock:
More clever mods and innovations. Great stuff! 8)


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PostPosted: Sat Dec 10, 2011 7:23 am 
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Location: Sarasota,Key West FL
I have to sell the Ultimate Tandem Island.

I am being tranferred for my job to Tempe Arizona, of course thats in the middle of a freeking desert and no where near any ocean (or water for that matter) so I must sell my Tandem Island. This can be someones oportunity to own what I consider the ultimate boat. I have about $9700 dollars invested in the boat (not including any of my labor designing and making all the extra sails and parts). I would like to get $6300 for everything if possible.

The hull and hardware is 2011 (replaced original 2010 hull in Spring 2011) with the new rudder systems. Replaced AKA bars and AKA cross bars in summer 2011. Replaced mast holder in summer 2011. (basically almost a new boat)
The bottom is scratched but other than that the Hull itself has no modifications or holes drilled. The boat is garage stored and very clean and everything works great.
Here is a breakdown of what I have
Image

For someone to buy a new TI with tramp options, life jackets, HD cart, and safety lights and anchor the total would be around $6100 dollars, adding a 2hp gas motor (or electic trolling motor) adds another $800 so to buy new would be around $7,000 for a brand new complete ready to go Tandem Island. I am selling the whole works for $6300, the boat can be used as a regular TI (all the add ons are optional and can be left off the boat. The new owner can either keep or sell all the extras, all the extras (sail systems, motors, roof rack systems, etc) are basically free.
I'm also throwing in the Malone roof rack system ($400) (for two boats), and a Hitch extender T bar system ($150) and optional winch system ($75) with the boat. I won't be needing them anymore in the freeking desert.
So this is someones chance to own the legend (total cost to me was way over $10 grand). I will also be posting this in the for sale section. I just wanted everyone to know whats going on. I'm very bummed and sad about this (really sucks).
All the extras fit on any standard Tandem Island, If an existing TI owner wants to give me $2300 for all the extras (huge deal), I can then sell the TI basic boat (unmodified) for $4000. I would need commitments on both to break them up.

Bob


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PostPosted: Sat Dec 10, 2011 8:51 pm 
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Bob,
Sorry to hear that you are being posted elsewhere and sans boat.
Think of the improvements you can in-vision for your glorious and future return to the water.
Just consider it as working your way to NOHUHU and the rest of Oceania with a minor stopover.

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PostPosted: Sun Dec 11, 2011 7:10 pm 
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Location: Kailua 96734
Yeah, - IN THE MIDDLE OF THE FREEKIN DESERT!! :(

Unfortunately, this pretty much sums up the sailing experience in Tempe.

http://www.google.com/maps?q=Tempe+Marketplace,+Tempe,+AZ&hl=en&ll=33.433053,-111.933239&spn=0.004368,0.006539&sll=33.353473,-109.588623&sspn=3.165775,6.696167&vpsrc=6&hq=Tempe+Marketplace,+Tempe,+AZ&t=h&z=18

My condolences, Bob. We will miss your marvels of engineering here.

But there's a bright side. Perhaps it's time to upgrade to a Harley. You may even learn to love the desert as much as I do. I pay good money every year to go on desert rides and hikes.

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PostPosted: Sun Dec 11, 2011 9:21 pm 
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At least his desert is in the US and the people speak English.... ok well some Spanish.
The hard part is seeing such a great boat for sale.

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PostPosted: Tue Dec 27, 2011 6:36 am 
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Try sailing at Lake Pleasant. Big, open lake with pretty good wind for AZ and less than an hour from Tempe.

Image

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PostPosted: Tue Dec 27, 2011 6:24 pm 
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Location: Hilo, Hawaii
Fusioneng,

Ditto on Lake Pleasant. Did a little bit of water ski'ing on surfboards (tow surfing?) in the early 90's there. Thinking back, lots of potential if I had a TI back in the days. Good boat ramp and park facilities.

Also, it's about a 5-6hr drive to San Diego from Tempe when you're missing the ocean waves a bit.

All is not lost...

cheers!

cliffs2yak


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PostPosted: Tue Dec 27, 2011 7:23 pm 
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Location: Sarasota,Key West FL
Thanks guys, I'm not as bummed out now


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PostPosted: Wed Jan 04, 2012 1:04 pm 
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was wondering if you could provide templates for the hydrofoil stand-offs??

Brad '11 TI


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PostPosted: Thu Jan 05, 2012 2:15 pm 
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Brad R:
I had several versions of Hydrofoils on the boat. The ones on the Mirage drives, basically just tilt the mirage fins to 10 degrees when the mirage fins are folded against the hull to create enough lift to stop nose diving. No rocket science, just 1/4 inch thick PE sheet cut to fit, and slipped over the mirage fins. They didn't seem to cause any additional drag when not engaged (like when your pedaling). But definately raise the bow up when you engage (by pressing the fins against the bottom of the hull). The mirage drive itself doesn't take any of the load (any more than normal pedaling), all the stress is obsorbed by the bottom of the hull.

All this stuff is pretty easy to calculate, you can download the lift hydrofoil calculator from Caltech at ( http://www.hydrofoils.org/Lift/lift.xls ). I designed the foils using Javafoil at ( http://www.mh-aerotools.de/airfoils/javafoil.htm ). The foils themselves are just a 1/16 aluminum skin folded over an aluminum frame. The frame is 1/8 x 2 aluminum, and 1/4" dia aluminum all screwed together, then the aluminum skin is folded over the frame. I used Bondo body putty to tweak the foil design. Basically I made a scraper template with the correct foil shape, then contoured the top surface using the template, everything is accurate to within 1/32" or so.

The Hydrofoils I made were just standard NACA 4415 foils. There are 4 foils 3 ft long x 4 inches wide and 7/16" thick. They were attached to 2 1/2 ft long 1/2 inch rods that were attached to the AKA knuckles (basically tied to the knuckles with spectra string by the end of the rod. The 4 foils angled down and outward at about a 15-20 degree angle. The end of each foil was about 1 to 2 ft out past the AMA. I had a piece of 1/4 inch thick PE (cutting board) that was around 6-7 inches tall that pushed against the bottom of the AMA hull and angled the foils to an attack angle of 9-10 degrees. The foils were designed to stay at zero degrees angle of attack until the boat reaches 6 mph, then the lift created by the foils overcomes the torsion bars in the cutting boards and allows the angle of attack to increase (to max 10 degrees). As the boat speeds up and raises out of the water, since the foils are angled downward at 15 to 20 degrees the foil area decreases. The foils are designed to raise the boat out of the water at 8 mph (boat weighs 442 lbs) and at around 15 mph about half of the foils would be out of the water, at 25 mph 3/4, etc, I doubt very strongly my design was capable of anything over 25 mph (if that). The sails try to tilt the boat so most of the time the foils on one side are totally submerged and the other foils partially submerged (trying to level the boat, kind of like the tri-foiler works). Nothing in the design puts any more strain on the boat than normal sailing would.

Some issues I had with the design are the additional drag created by the foils makes it very difficult to get to the 7-8 mph required to get the boat to rise. I ended up doing like Dan Ketterman does with his trifoiler and used the outboard to help get through the double drag zone (hull and foil drag). Since you have both the hull drag and the foil drag until you get up to lift speed it makes it very difficult to get the boat up to 7 mph. I was able to get the boat up only twice, and both times was with a strong downwind with the 135 sq ft spinnaker flying. It's only once in a blue moon we get good winds here in Sarasota. As the boat speeded up to around 15 mph, the foils started to flutter (pretty badly) so I had to back off. The foils were held by spectra string (tied to the bow), and obviously more strength was needed. I spent a couple fun weekends fooling around with the foils ( I like designing things), but gave up on the foils last April and have not touched them since, it was a fun learning experience, but not very productive or practical. I've since sold the boat, since I'm moving to Arizona, where there is no water. I looked around for the designs, but didn't keep any of it, I had a computer crash last spring and lost alot of stuff.
Bob


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