I have sort of doing experiments with small outboard motors. The challenge is to achieve the speed to get over the hump, after that the required power is less. I am sure the wedges will work, but applied in a different way. Using a canoe like narrow hull to achieve the speed, and then lowering the wedges, simultaneously lifting the hull out of water, might do the trick. But i hope Your version will work though, good luck!
@markpalmquist
20 күн бұрын
@@joeordinary209 that is a good idea too, deploying 4 small skimmers at once above 6 knots.
@adrianperez3375
21 күн бұрын
This is a really exciting project. Im glad you gave it context in the other human powered vehicles. Good luck. We are cheering for you.
@markpalmquist
20 күн бұрын
@@adrianperez3375 thank you! I meant to also compare the surface area of the wing of the Gossamer Condor to the surface area of the skimmers but forgot to mention that.
@adrianperez3375
20 күн бұрын
@@markpalmquist it's always interesting to see if there are ratios between different regimes. I bet there are some really cool ones.
@markpalmquist
20 күн бұрын
@@adrianperez3375 yes, we know sea water is 830 times more dense. If you take the total surface area of the Gossamer plane 98’x7’x2 you get 1372. Divide that by 830 and you get 1.65 SF. Considering the efficiency of a flat plate is less than an airfoil, multiply 1.65 x 1.5 and that’s how much hydroplaning surface you need to lift the same weight at the same speed, about 2.5 SF of skimming surface will lift about 230 lb at 18 MPH.
@adrianperez3375
20 күн бұрын
@@markpalmquist So that means you are approaching the same advantageous efficiencies as the gossamer albatross. I wonder what a boat/ship made of thin plastics and carbon fiber effects things.
@MrJlcurl
13 күн бұрын
This is a really cool project, I'm a rower and a sailor, and I look forward to what your experiment shows. Thanks.
@markpalmquist
13 күн бұрын
@@MrJlcurlThanks! I think it is possible I just think I might be 15 lb too heavy to get over hump speed. The hump speed goes down the lighter the total load.
@RulgertGhostalker
21 күн бұрын
call the Wedge Rower is a NeverWet Super Hydrophobic coating test bed. ( maybe you can get a discount for the NeverWet promo? ) it will take less power to keep it in a plane, than getting there .... if it doesn't work, then get some NeverWet for the wedge skimmers.
@bobcornwell403
19 күн бұрын
Interesting theory. But I think you need a propeller for this to work. The reason I say this is because a propellor provides steady power, whereas oars provide pulse power. I once got into an interesting argument in the pdracer community. My argument was that a heavier puddle duck would row better than a lighter one. Sure enough, someone put my theory to the test. He rowed his boat empty than successively tried it with more weight added. He rowed at least a half mile each time. And sure enough, the heavier boat was significantly faster. The reason for this is that it didn't lose as much speed between strokes. Now, a lighter, much longer boat would assuredly be faster, especially if it was also quite narrow. This is why kayaks are so fast. Weight per beam is much more important than weight per length in this case, because this gives you momentum to coast between strokes.
@WillN2Go1
19 күн бұрын
Kayaks are not fast. When I was 50 I was able to consistently average 4.3 knots over three hours on the ocean, Santa Monica Bay. In the kayaks I've built since (both longer and narrower) not even close. (also I am older). Speaking with the guy working for Northwest Kayaks he told me a canoe is much faster than any kayak. Said it skims. I think the kayak I did these speeds in was more canoe shaped than kayak. Nick Schade design Great Auk, strip built (17.5' 23.5" beam. The others were 18' x 17" and 19' x 17") (I think I remember Nick saying the design wasn't canoe like. He knows a lot more and it is his design.) I'm hoping to make a paddling rig for a Stand Up Paddle Board. It would need a footrest and minimal flex. SUPs are usually faster than kayaks. They skim. If this subject interests you, build models and test them. Just discussing it takes up a lot of time and really doesn't get anywhere. (And no one is more guilty of this than me.)
@my_dear_friend_
18 күн бұрын
@@WillN2Go1 - I cannot imagine that any current watercraft (kayak, canoe, SUP) that is solely propelled by a human with a paddle on flat water will leave displacement mode and begin planning/skimming. Flatwater racing SUPs have displacement hulls and all flatwater racing kayaks and canoes have displacement hulls. For good reasons. Add a sail and wind or waves to ride down, ...different story. By the way, the current flatwater world record for 1000m kayak is at about 3min22s, for canoe at 3min46s. SUP is slowest. The 2023 world record for 200m with a SUP is slightly above 44:37 seconds, so about 4min15s for 1000m (unrealistically assuming one can continue at that pace for 5 times the distance).
@khelek100
19 күн бұрын
I live in a desert but I'm curious to watch your design adventure.
@myperspective5091
6 күн бұрын
I was just watching some water slide videos. I looked for one in particular. Everglide or Aqua Chute at Adventure Island Amusement Park in Tampa Florida. Your boat reminds me of two of their sleds in tandem.
@markpalmquist
6 күн бұрын
Yes, very similar. They have a good shape.
@myperspective5091
5 күн бұрын
You boat was reminding me of something else. It reminds me of a pre WW1 canard floatplane called the Viosin.
@markpalmquist
4 күн бұрын
Yes, very similar indeed😎
@colin7242
20 күн бұрын
Your biggest challenge will likely be maintaining speed during the part of the stroke when there is the most "check" on the boat, when the rower is furthest astern but not yet applying power through the oars. Foiling rowing shells have struggled with this, and the only solution I'm aware of is a sliding rigger design (where the entire rigger and seat assembly is floating, so the center of gravity is fairly static. Sliding riggers are illegal in competitive rowing, so there's not much work being done on that front, but it would be perfectly viable for a recreational project like yours. Really interesting design!
@markpalmquist
20 күн бұрын
@@colin7242 I am open to trying that if test 2 is too pitch unstable.
@GlenWatson-os9ri
20 күн бұрын
I’ve enjoyed your videos and have learned a lot from them. You inspired me to change the design of a trimaran conversion of a Snark such that I am tilting up the forward amas by 2 degrees and having the bottoms of the amas have a v-hull shape to them to hopefully generate lift (more than I would’ve expected from parallel amas using buoyancy alone). So thanks. I appreciate your insight.
@markpalmquist
20 күн бұрын
@@GlenWatson-os9ri sounds good, glad to hear it, thanks.
@CraigOverend
20 күн бұрын
I've modelled a hull in FreeShip where my criteria was to have two 5° flat planes for lift, one fore and the other aft with a step in between. I also wanted to maintain a centre of buoyancy somewhere near the middle at different displacements. I was very surprised by the resulting shape. Top down it looks like an arrow with continuous taper. Looking from aft it looks like a triangular transom. The stern is very wide at min displacement and gets narrower at max displacement (hence the triangular shape), while midship where the step is, is about a third of the width of the stern at min displacement and maybe half width at max displacement. I also modelled a round bottom hull (minimum surface area to displacement) to compare with, and the drag was very similar at full displacement. That's as far as I got with that thought experiment.
@markpalmquist
20 күн бұрын
@@CraigOverend interesting, thanks for sharing. I have not tried free ship yet. My angle is 4 1/2° but the front half of the wedge is 8° however, now that I made modifications, the location of the waterline at rest is lower so hopefully the initial drag will not be too much to overcome.
@myperspective5091
6 күн бұрын
A solid combo might be to add the Oar Board rowing rig to a design that is a smaller version of the Circus Circus canard hydroplane style hull, or to something like the Lee Taylor Discovery 2 rocket boat hull, or to a small mono hull boat like a Thailand long tail river racing boat hull.
@markpalmquist
6 күн бұрын
I’ve been studying the Thailand long tail river racing boats. They are very close. I agree, the Oarboard would be great.
@WillN2Go1
19 күн бұрын
The Aleut (Unangan) kayakers in iqyax (baidarkas) were observed in the 1770s by Captain Cook's navigator as traveling "10 sea miles an hour," (10 knots). This would've been one of the more reliable observations possible in the 18th century. When the Russians occupied the area forcing the Aleuts to hunt for them, they banned the fast iqyax designs because they could out run any Russian vessel. George Dyson in about 1990 wrote a scholarly article about the baidarka which included some calculations. These calcs determined that iqyax if they were able to make these speeds they had to be planing. I built an iqyax based on the 1803 design from Leningrade (St Petersberg). Of course I didn't get anywhere near these speeds. In fact my 'iqyax was kind of slow. (My fastest kayak was a Great Auk 17' that I think was more like a canoe than a kayak. I consistently averaged 4.3 knots over three hours.) Studying and building the iqyax, I think I figured out a couple of things. First to get a vessel like this to plane I would have to be able to sustain at least 7.5 knots, which would probably be at least 4x my possible sprint speed. (So not going to happen.) Second and more interesting. If you look at the bottom two stringers on either side of the keelson of a 'baidarka' you'll notice that in the historical examples there is a big gap. There's no structural reason for this gap. Even spacing makes more sense. On the water, the skin depresses between the stringers and the keelson, forming two curved channels. Simplified in a two dimensional sense is, these channels scoop water in from near the bow. The channel narrows until it reaches the CG of the paddler, and then they're parallel all the way back. I think it is water entering these two channels which lifts the 'yak allowing it to plane. But you would have to be able to get up to 7.5 knots for this to happen. I don't think my iqyax is a suitable test platform, but the obvious test would be to tow it, or put a motor on it. What should happen is that as velocity increases, effort will also increase (at a greater rate) and once planing is achieved the effort should diminish or at least not continue to rise. Then the question would have to be answered, is this possible with only human exertion? Always tests. Flume tests.
@FranklinBryan
21 күн бұрын
So cool. I'm loving these posts. Thank you for sharing
@markpalmquist
20 күн бұрын
@@FranklinBryan thanks! I hope it works. If not I will learn something insightful anyway.
@davidtomasetti8520
20 күн бұрын
I played with surf hydrofoils for a couple years, I approached it more from intuition than math, but I think you may be surprised how easy it is to get flying,, the harder part I have found is control..
@BenjaminT.Minkler
20 күн бұрын
take a look at the 1978~92 *WetBike* (as first seen in the Bond movie: The Spy That Loved Me) altho it has a two stroke ICE engine and jetpump drive they 'plow' to get up on 'plane' with their two hydroplaning skis at pretty low speeds - even tho they are very heavy, and can do it with two riders ....the dual ski design is somewhat along the lines of what you are after with your 'skimmers' but it appears you are trying to also use them as flotation(which I think their huge size might just cause extra drag at the lower speeds making you fight harder to break onto plane!) instead the WetBikes still have a somewhat sleek under hull to awkwardly float at a rest and at trolling/'plowing' speeds(altho very unstable until up on plane, because of the higher center of gravity with engine, fuel tank, battery, and rider - however this high up CG actually adds to the maneuverability once the WetBike is totally above the water as it functions then like a motorcycle/bicycle with slight counter steering and all the weight much above the contact patch 'falling' in the direction you want to turn by quickly moving the light weight skis/tires out from under it in the other way....anyway, that could be important to you for stability once above the water line!) but do look at the WetBike's skis, as you might not need yours to be so large with so much drag, as these others do lift a really big amount of weight at lower speeds than you might expect - I'm assuming a lower weight human powered craft could plane up on even just the same WetBike skis(altho they are very heavy thick fiberglass to withstand wave jumps and stuff) pretty easily if you can run at a smooth steady speed, I'm guessing rowing wont cut it especially with a high drag large overly long/wide wedge - you will want the hull to float ya and be able to get to planing speed
@myperspective5091
9 күн бұрын
This idea might be interesting. See if you can measure how fast skimboards go and then use that as the speed that you would need to go to achieve your goal.
@markpalmquist
8 күн бұрын
Thanks. Yes, that is a good starting point. It is hard to measure the angle of attack that one arrives at after jumping on the board. AOA effects lift and drag and so does surface area. Every speed has a different amount of lift that each square foot can support. If the mass remains the same, then with every increase in speed, wetted area will shrink as the boat rises further out of the water. My current floats do not have enough buoyancy to keep the water off the tops of the floats. The water that gets on top prevent it from lifting. I think I will make several scale models with different shapes and see what has the least amount of drag. So a skim board supports 160 LB with 4.7 SF at around 10 mph. If you have 2 boards you can support double the weight or you can support 1.5x the weight at a slightly lower speed. That is what I am aiming for.
@Sneakymacd
19 күн бұрын
Interesting concept. Why is your boat so heavy? A normal skiff weighs less than half. Even a double isn't that heavy. Losing some of that weight will make it significantly easier to get up to the required speed to start planing.
@markpalmquist
19 күн бұрын
It was initially 50 lb but went up with the float changes and addition of the rowing frame. I agree it could be lighter. The floats have more surface area than a long and skinny hull but wetted area will go down when the boat lifts.
@myperspective5091
6 күн бұрын
On a side note: Have you seen the Hingham high school rowing team pulling a water skier?
@markpalmquist
6 күн бұрын
@@myperspective5091 no. Sounds interesting. I will check it out!
@markpalmquist
6 күн бұрын
@@myperspective5091 I just watched the video. Did you know the lift to drag ratio of water skis is quite low? A skim board going sideways has 40% more lift and less drag. So at a minimum 5 people could pull someone on a skim board out. However, the long and narrow hull has zero dynamic lift therefore its surface area remains the same but its drag increases with the square of the velocity, a skimming hull will lift with increasing speed and its drag will go down after getting over the hump speed. It may end up that I would need 2-4 people rowing to get over the hump speed. With every person you add, top speed increases by 8-9%. The reason it is that low is that the length and displacement volume increase when you add someone , but 8% adds up.
@macrumpton
20 күн бұрын
I have to imagine that someone out there has tried to row one of the small outboard hydroplane hulls that were popular back in the 60s. in any case those small hydroplanes give you an idea of what kind of horsepower is necessary. While it might be possible to stay up on plane by rowing, I think the power needed to get up on plane is way too high for a person to generate
@markpalmquist
20 күн бұрын
Most peoples experience with hydroplaning is with a motorboat. When you think about the force on your arms when you’re being pulled out of the water on water skis by a boat, it’s not much different than the force of you pulling on rowing oars at full force plus when you’re being pulled up out of the water on water skis by a motorboat, your skis are more or less vertical and there is much more drag.
@macrumpton
19 күн бұрын
@@markpalmquist I see your point, although, if I think of being in the water with water skis on and trying to pull on a rope to get myself up on a plane, it seems quite impossible.
@FranklinBryan
21 күн бұрын
Your Dad is smiling down watching you carry on!
@markpalmquist
20 күн бұрын
@@FranklinBryan he would love this project, I agree 😎
@mckenziekeith7434
20 күн бұрын
I think the issue is going to be the hole shot, so to speak. Even if you can supply enough power to go some distance up on plane, almost by definition, you will need to temporarily supply much more power to get up on plane in the first place. Can you do that? Looking forward to it. Also, the people who set these world records are often very fit athletes. So keep that in mind.
@markpalmquist
20 күн бұрын
@@mckenziekeith7434 I may have to recruit a fit athlete, definitely
@moroteseoinage
19 күн бұрын
You’re about as dynamic a speaker as Ben Stein.
@markpalmquist
19 күн бұрын
I agree.
@myperspective5091
9 күн бұрын
I’ve never said this to another engineer, but that is going to fail. Getting a human powered row boat to plane will never happen. There is a reason that rowing sculls, surfskis, and sprint canoes are designed the way they are. It is because those long narrow smooth rounded tapered shapes are the fastest shapes for paddling or rowing.
@markpalmquist
9 күн бұрын
The ideal shape of any hull changes if you are able to go over the hump speed. Once over the hump speed, the ideal shape is wide and flat with 4.5 degrees of incline. Hydroplaning is only 10% less efficient than hydrofoiling.
@myperspective5091
8 күн бұрын
@@markpalmquist Because you will be paddling for your thrust your thrust will come in spurts. In between those moments of thrust you will be repeatedly dropping / panicking back down into the water. You will be repeatedly trying to climb after each drop. On a side note: Surfers can pump on the downward drop and then lift back up when the water rebounds back upwards. They are surfing that little swell they make. That is why the skim boarders can stay up as long as they do when the pump their boards. That is also why thinks like the Aqua Skipper worked. The hydro foils have more vertical travel then hydroplanes. That gave the rider more time to build up strength for their next push before they bottomed out.
@markpalmquist
8 күн бұрын
@@myperspective5091 pumping works on sails and fins that have fluid flow on both sides. Hydroplaning does not require pumping it just requires a certain speed and a certain weight per unit wetted area. All our experiences with hydroplaning are with low aspect ratio surfaces, not idealized. Wetted area should be 3 times as wide as its length to get ideal lift per unit area. Motor boats and windsurfing boards are idealized for pitch stability not max lift per unit area. That is why I need 2 floats instead of 1, to maintain ideal AOA. If windsurfing boards had stepped hulls they too would be able to hydroplane at lower take off speeds.
@RulgertGhostalker
21 күн бұрын
vert transom some Tows water, ( no go ) slanted aft Lifts water, ( no go ) slanted fore and the water surface tension sheds down with gravity
@markpalmquist
20 күн бұрын
If this second test does not work I will slant the transom forward and try again.
@RulgertGhostalker
20 күн бұрын
@@markpalmquist i suppose that means they are already done and part of the boat?....your thoughts on high aspect are correct, with high aspect you would have a shorter bow wave, not as high of a bow wave, and only smaller bow waves beyond the fundamental frequency... no one wins any argument against physics ... so stick with the program, and consider my explanation of the physics here; because i couldn't change that reality if i wanted to either.
@RulgertGhostalker
20 күн бұрын
so basically, you want to have the boat floating on two "trailing edges" ( as in foil speak )....surface tension means water wants to stick to everything, including itself.
@RulgertGhostalker
18 күн бұрын
@@markpalmquist I mean you calculated your optimum aspect ratio and angle....what was wrong with that? .... nothing when it was just a board...but you need that to be the flotation this time, so static displacement is where they start.
@markpalmquist
15 күн бұрын
@@RulgertGhostalker almost ready to test. We’ll see if it will get over the hump speed as is.
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