Revolution Mirage test drive

Wonderful discussion!  I have LOVED my Adventure for 3 years now.  I do 5 hours at the petals frequently with no before hand training and loving it.  I am moderately active normally, so don't be afraid.  Depoe Bay or off the beach in a calm ocean is the best. 

From Wavewalk.com:

                             
Kayak Speed Fundamentals, the Twinhull Advantages and the Principles of the W Kayak Concept



Hull speed is just another term taken into consideration in the process of designing a boat, and taken out of a broader context it is meaningless:  If you made your house watertight and put it in the water it would have a higher hull speed than the world's fastest paddlesports boat just because it is longer... It doesn't mean the house would actually be a fast vessel. 
Hull speed is by no means a final limitation on speed, and it's very common for boats, including human powered ones to go faster than their hull speed. 

Different strategies for increasing boat speed
1.    Add power:  With a strong engine and a big budget for fuel you don't have to worry too much about the energy spent on going faster than your 'hull speed'.  The same goes for a stable sailing boat with lots of sail power.
If you want to add power to a human powered boat you need to find a way to add more groups of muscles to the propulsion effort by offering the user/s a better posture i.e. biomechanical improvements, and/or means to reduce discomfort and fatigue i.e. ergonomic improvements.
2.    Add length:  That's applying a 'delaying' strategy - You delay the occurrence of the steep increase in residual resistance by paying in increased frictional resistance that you get from having a longer hull.  This strategy is good as long as you have the additional power needed to overcome the additional friction.   Another problem you'd have to deal with is a decrease in your boat's maneuverability, which is more of a problem in human powered boats where the additional power needed for maneuvering is taken away from propulsion.
3.    Reduce residual resistance:  A good strategy for a human powered boat with only human muscles for propulsion.  Very thin racing canoes and kayaks generate relatively little residual resistance even after when they go at speeds that are higher than their hull speed -  This is why they create relatively small waves.
 
The boat's 'fineness', often described by its Length to Beam ratio (L/B) at waterline is most useful for predicting its speed:  An ICF K1 racing kayak has an L/B of 11:1.   This kind of boats have low displacement and are very 'fine', which makes it possible to paddle them at up to twice their hull speed. 

Speed in human powered boats
Adding power for propulsion is not relevant for canoes and kayaks unless the boat is designed to carry more paddlers (i.e. have more power), but it's good to keep in mind that a boat offering a better paddling position, improved stability and control, and the comfort of being able to reduce fatigue and prevent injury by changing positions adds to the paddler's effective propulsion and therefore may achieve and sustain higher speed.
The Comfort factor and the ability to sustain the physical effort over a longer period of time with less fatigue and no injury pertains to Ergonomics, and the effective power available per paddle stroke pertains to Biomechanics.

Making the boat longer is good for as long as increasing surface area does not end up in slowing you down.
Reducing Residual resistance is severely limited by the width of the person sitting in the boat but why sit inside the hull?...
-Rowing shells are faster than racing kayaks not only because of their great length but also due to the fact the rower sits on top a hull that's narrower than his waist - A rowing shell's L/B is much higher than that of any racing kayak.

Displacement/Length (D/L)

"High speeds for canoes are only made possible through their having excellent Displacement/Length ratios and narrow beams. The two combine to produce very small waves which are the major resistance at speeds above S/L 1.34."
The low sitting position in a monohull kayak is wasteful in terms of paddler's energy since a small and relatively weak group of muscles in the shoulders, chest and back has to provide most of the propulsion and control efforts, while other, more powerful and better fit parts of the body are largely prevented from sharing the load and increasing available power. 
Sitting low also makes it more difficult to make the paddle move in parallel to the hull and at a close distance from it.  Instead, the natural movement of the blade is more in parallel to the water surface, in a curved course at a distance from the boat.  This leads to high energy loss as a result of the difference in speed between the paddle's tip and the part that's closer to the shaft, and because the paddler needs to put more effort in keeping directional stability.
Since the paddle moves at a low angle relatively to the water surface the difference in resistance between the blade's low (more submerged) and high parts creates an unwanted rotational effect with the shaft acting as axis.  Overcoming this problem is achieved by a combination of the paddler's continuous effort ('technique') and an asymmetrical, thin (less full) and consequently less efficient design of the blade.   
Most fast kayaks (and canoes) have hard chines that increase their wetted surface i.e. further distance them from an 'ideal' shape in speed terms. and

Excellent review KT. I've always thought the Revo is the most versatile 'yak in the Hobie line. It really lets you fish any body of water. If I didn't hit the sound and sea so much it'd be my choice for sure.

Z

I've been looking around for prices on a Revo Mirage, turbo fins, and sailing rudder.  There is also a "Mirage drive spare parts kit" ($100).  I like the idea of having some spare parts in the truck.  The boat will spend most of its water time in the salt, so corrosion is a concern.  "The Spare parts kit includes one ST Turbo fin, mast, sprocket, set screw, allen wrench, chain, clevis pin and ring and a cotter key. All in a handy zippered pouch."

Turbo fin replacements are $28, masts are $17.  I couldn't find the chain or sprocket separately.  Allen wrench, stainless screws, clevis, and cotters I can get elsewhere. 

Which parts on the drive are the weak link(s)?

Which parts on the drive are the weak link(s)?

Easy, none. I think anyone who uses their MD a lot and sprayed it w/ fresh water after being in the salt and a few sprays of WD40 every 10 trips or so will tell you not to worry. I've never had any MD problems. Only damage I ever did was when I was hauling butt and came to a shallow spot w/ rocks and bent a mast when I hit them.
My bad.

Z

 I couldn't find the chain or sprocket separately.  Allen wrench, stainless screws, clevis, and cotters I can get elsewhere.  

http://www.austinkayak.com/catalog_products.php?SubcatID=317004&sort=ProdName&order=ASC&maxRows=ALL

http://www.austinkayak.com/products/1571/Hobie-Mirage-Chain-Assembly.html

http://www.austinkayak.com/products/1283/Hobie-Mirage-Drive-Replacement-Injection-Molded-Sprocket.html

As a side note. I have never broken any of these things. That's after 4 years and I am hard on gear.

That said, I have bent a mast a bit and torn the tip of a turbo fin, but nothing I could not fix in the field. I have also had the mast come loose and found myself in need of an Allen wrench. So having a tool set is imperative. But even that mast issue has been addressed with the screw-in mast.

Never hurts to have spares though
(must be an airplane thing )

  


 Leashing the beasty is the most crucial thing though and a spare drive most definitely would be handy if you don't 

Thanks for the replies.  I think I'll just get a spare mast and turbo fin to keep on the boat.  I will always have a paddle.

Took the Revo out for its first fishing trip to Potholes and Moses Lake, and spent 9 hours on each lake.  After 18 hours of fishing from the Revo, I REALLY love the mirage drive, and still hate the Twist-n-Stow rudder - mine no longer deploys.  After 18 hours of kayaking over 48 hours my elbow feels fine, so the decision go with the Revo and trade-off space for hands-free propulsion was a good one for me. 

I can easily cruise at 3-3.5 knots indefinitely, and I swear if I could just peddle a little bit faster I could get the yak up on a plane.  4.5 kts with some effort and 6 kts peaks.  The thing flies!   The sailing rudder will turn it on a dime, and it's fun sprinting off and pegging the rudder to spin out.

The little hatch tray is very handy in the crotch hatch, but just leave the tray lid off.  The mesh side pockets are also very useful.  The built-in rod holders are useless, being too far back.  The live well is very shallow and a milk crate is a must.  Fish bag was held down by the bow bungee lacing, but next time I think I secure it behind the milk crate in the rear of the live well. 

I am going to re-purpose the front hatch bungees as tackle box hold-downs on either side of the drive.  A bungee hook could be added to the bottom front screws on the mesh pockets.  This may make the cockpit too cramped, but I'll see.

Previously I was concerned that I would not be able to carry fishing gear and crabbing gear together and after spending a lot of time on the boat this is obviously true.  This space limitation is somewhat mitigated by the speed of the boat.  One could rig for crabbing, drop the traps, and return to pick up the fishing gear, then upon return, drop off the fishing gear and return to pull the traps.
 

Which parts on the drive are the weak link(s)?

Easy, none. I think anyone who uses their MD a lot and sprayed it w/ fresh water after being in the salt and a few sprays of WD40 every 10 trips or so will tell you not to worry. I've never had any MD problems. Only damage I ever did was when I was hauling butt and came to a shallow spot w/ rocks and bent a mast when I hit them.
My bad.

Z

I agree with Z 99%. The new designed, V2 Mirage Drive has a much better drum design, the version 1 unit like i have puts more strain on the cable ends, i could see that failing sometime. That being said i have used mine for going on 3 years and they haven't broke yet, but are looking a little worn. I'd love to get a new ride this year, i might try out a Revo.

Also, if you leave the hatch gear tray lid off in rougher conditions the tray will fill with water from dripping(more like pouring) everytime you open the hatch.  Love the crotch hatch. It's great unless you let your middle expand too much over the winter...

I agree with Z 99%. The new designed, V2 Mirage Drive has a much better drum design, the version 1 unit like i have puts more strain on the cable ends, i could see that failing sometime. That being said i have used mine for going on 3 years and they haven't broke yet, but are looking a little worn. I'd love to get a new ride this year, i might try out a Revo.

The drive is a wonderful gem of design, engineering, and execution. 

Also, if you leave the hatch gear tray lid off in rougher conditions the tray will fill with water from dripping(more like pouring) everytime you open the hatch. 

Another great design feature of the Revo.

Question:  The hull profile of my Revo has a mildly concave section between the cockpit and the stern.  The bottom of the hull is flat along this area with a cross section like that of a squished balloon.  Is this normal or is my boat warped?  If it is part of the design what purpose does it serve?  In wind chop it creates a frequent hull slap.

I have the same thing, I think it came from not storing the yak upside down, but right-side up on the wheels. 

Y'all may have noticed I have not become a big fan of the Revo boat, though I am a HUGE fan of the mirage drive, but still, it is hard to believe the Revo hull cannot support its own weight out of the water.  I assumed it was some esoteric hull design for an extra fraction of a knot or added stablity.  The "depression" does not correspond with either location where the Wheelez cart cross-members contact the bottom of the hull. 

Y'all may have noticed I have not become a big fan of the Revo boat, though I am a HUGE fan of the mirage drive, but still, it is hard to believe the Revo hull cannot support its own weight out of the water.  I assumed it was some esoteric hull design for an extra fraction of a knot or added stablity.  The "depression" does not correspond with either location where the Wheelez cart cross-members contact the bottom of the hull. 

Is it soft in that area? RevoRoy had a problem with the bottom being soft and flat on his first Revo, they replaced it with a new one.

I just discovered on Sunday that I can put the drive in backwards and go backwards.  Going to have to try it pulling plugs on the river for Steelhead this summer.  Seemed to work OK in still water but I'm wondering about in currents.

Y'all may have noticed I have not become a big fan of the Revo boat, though I am a HUGE fan of the mirage drive, but still, it is hard to believe the Revo hull cannot support its own weight out of the water.  I assumed it was some esoteric hull design for an extra fraction of a knot or added stablity.  The "depression" does not correspond with either location where the Wheelez cart cross-members contact the bottom of the hull.  

Is it soft in that area? RevoRoy had a problem with the bottom being soft and flat on his first Revo, they replaced it with a new one.

Yes, I've been surprised at how soft is the bottom of the hull.  Oh, shit.  I REALLY don't want to do all my mods over because of a crappy manufacturer.  I guess I'll take a photo and send it off to Hobie.   And they charge a premium for the "Hobie" name.