Boat Definition and 366 Threads

I have a small catamaran that used to have two motor under the hulls spaced 2.7m apart. I've replaced those motors with outboards which are spaced 1m apart, and placed about 4.2m behind the centerline of the boat. Initially it was impossible to use differential thrust to turn the boat, but since...

1. Is it possible that sailing boat(going backward) turns less when rudder is full right, then rudder is at some smaller angle? Due to too high AoA and flow separation/stall, trailing edge of rudder is sharp that also lower stall AoA... 2. Analysis waterflow when object move at curved path...

I'm not sure if you would call it a "Parallel Impeller," but the pics below should tell the story. I'm designing/3D printing my next RC boat from scratch, and I wanted to try something different from tried-and-true propeller and shaft system. Reasons? 1. Fun. 2. Using a "wet" brushless motor...

A sail boat got stuck because there is absolutely no wind. The boat happens to have some powerful fans. Which are then bolted on deck and blow to the sails. Would that make the boat move? When the artificial wind direction is horizontal (0 degree) When the wind direction is 45 degrees. Would...

I'm assuming the boat is traveling north at an 8 m/s and the river is flowing east at a 2 m/s. For the boat to move in a straight line, it has to aim at an upstream angle given by #theta#. Using SOH CAH TOA, ##v_r = 2m/s##, ##v_b = 8m/s## $$\theta =\sin^{-1} \frac{v_r}{v_b}$$ $$\theta = 14...

I am confused by the question. So, the first thing I am trying to understand is whether the flag direction will be same to a boat observer as to a ground observer. I know that the flag will orient itself in the direction the wind is blowing towards, so the flag should always point in NE...

My boat (Mac26) is not revered enough for anyone to have bothered to data model its shape. My Mac26 friends have all expressed an interest in getting their hands on it. I've been trying to think of an expedient and cost effective way of modeling it in data form. One way is to place...

vcanoe_wrt_ground = 3 m/s + (-6) m/s = 3 m/s - 6 m/s = -3 m/s Thus, if I understand this correctly, the rower will never reach his goal 36 m away as his canoe's resultant velocity is negative (i.e., his canoe is effectively going downstream even though it is trying to go upstream). My only...

Apply Principle of Archimedes - upward force is equal to the weight of the volume of water displaced. Density (boat) = 120 kg/(3x1x.24)m(3) = 500/3 kg/m(3) Density of water = 1000kg/m(3). Density (water)/Density of boat = 1000 kg/m(3)/(500/3) kg/m(3) = 6. So density of water is 6 times the...

In small sailing boat like optimist is well know technique when there is no wind, rudder pumping which push boat forward.You just need push-pull rudder left to right with fast movement. 1) Rudder is stiff(not flexibile like flippers for diving),so why rudder produce forward thrust if high and...

I was hoping to explore the Calculus of Variations. How do we prove by Calculus of Variations that the minimum time for boat crossing a river (perpendicular to the current for starters) with current ##v_r##, and boat velocity in still water ##v_b## that the path will be a straight line? I...

New trailer and new self built boat. Need confirmation of my calculation for placement of boat on trailer to have the correct tongue weight. For those not familiar with trailers: The tongue of a trailer is the forward beam that has the female ball receiver at the front end. It is imperative...

I have a boat that weighs about 100 lbs. and is 10’ long. I’d like to load it on my pickup rack in the manner shown in this (and many others) video, but without having to purchase and mount a winch. I’m fairly certain I can get the boat upright. The portion I don’t know how to calculate is...

So I've been thinking for a long time now about making a self-submersible boat out of a plastic bottle without electronics. It should resurface by itself after a few minutes. I was thinking that it might increase its volume. By slowly dropping weights down the bottle and opening flaps on the...

Is it possible to determine the length of the boat by using the physics of the shrapnel arcs? Can the traces of the arcs be used to determine the distance the shrapnel travels and then be send to determine the boat length. Tex

I want to calculate the angle of a wooden boat at rest in salt water, with a 55 lb outboard motor mounted on the transom + 3 gallons of gasoline (18 lbs) + 2 adults weighing about 150 lbs each. So just figure a total weight at the back end of the boat being 55 + 18 + 300 = 373 lbs. The boat...

FAx = F cos 40 FAy = F sin 40 2FAx = Drag Drag = 6128N The answer says 6200N

I'm trying to calculate the maximum Force in PSI applied to the transom of a planing boat under acceleration using F=ma. boat mass is 300kg accelerates from 0 to 10m/s in 6 seconds F=ma -> 500N = 300kg *(10m/s/6s) = 112.4045lbf the contact area between the boat transom and motor is 1000 mm2 =...

Building a 8' x 12' platform that will hold a small boat next to my dock. The platform needs to be able to be lowered below the surface of the water (launch boat) and lift above the water (store boat). Four pilings (one each corner) that each have an electric motor & reduction gearbox that has...

Equation for the tide: $$y=-\cos \left(\frac{2 \pi}{6}t\right)+2$$ When ##y## = 1.5 m : $$1.5=-\cos \left(\frac{2 \pi}{6}t\right)+2$$ $$-0.5=-\cos \left(\frac{\pi}{3}t\right)$$ $$\frac{\pi}{3}=\frac{\pi}{3}t$$ $$t=1$$ But the answer key is t = 2. Where is my mistake? Thanks

This is the image of the problem I tried to solve it and I got the following is it correct?

From equation (3.7) , we know t = d/v_y = d / v_ABcosθ = d/ v_Asinβ Now for time to be minimum , denominator must be maximum this implies θ=0 and β=90, but this doesn't make sense as when we try to row the boat at 0 degree with y-axis due to stream it will have a some net velocity which will...

I'm planning to build a 12 foot jon boat that will be car topped on our van. The rated loading on the roof racks is 165 lbs. To weigh the finished boat, I plan to do the following: Position the boat upside down in our carport. Stand on a bathroom scale and lift the front of the boat. Write...

In competitive rowing, the more people in a boat, the faster it goes, but what is the ratio of additional human to speed, and what is the theoretical limit? If I could fabricate a boat where each additional person added 100kilos, 100watts of power, and 1 meter of length to the wetted surface...

BACKGROUND: I'm thinking of building a flat bottom Jon boat. We don't have room for a boat trailer so I want to load the boat on top of our 2019 Honda Odyssey van. Without a trailer, the boat can be stored on a side against our hollow tile wall. The dimensions of the boat will be: 12 feet...

v upstream = 5 - 3 =2 v of the water = 3 arccos = (2/3) = 48.19 v across the river = c^2 - a^2 = b^2 √3^2 - 2^2 = 6m/s t = 80/6 = 13.3 can someone please point out my mistakes? am I even supposed to solve for angle like this or "perpendicular to the shores" just means that the angle is supposed...

Attempt : I begin by plotting the graph of depth x against mass of pellets m as shown alongside. Using ##m_B = \Delta m_L\Rightarrow m_B = \rho_L A_B\, x(B)## where ##\rho_L## is the density of the liquid, ##A_B## is the cross-sectional area of the boat and ##x(B)## is the depth to which the...

2500 N [south] + 3200 N [south] = 5700 N [south] 5700 N [south] - 6000 N [north] = 300[north]

Hi there, I have attached the problem I'm working with. I believe I must have the wrong idea of how to approach this question. My issue is with the stated width and calculating how long the boat will take to cross the river. It's using width; 110m and the boats velocity to determine how long...

Let’s say we have a boat whose longitudinal axis is the y-axis (which goes into the screen in the figure below) standing upright in a still water . ##S## is the Center of Mass of the boat and ##C## is the Center of Mass of the displaced water.On ##S## lies the force ##\mathbf W##...

First off, to solve for this problem, I relied largely on my below drawn diagram. Forgive the poor work as this was done on a laptop. Using the above image as reference, I came up with the below equations. $$\frac{dy}{dx} = \frac{sin \, \theta}{1- cos \, \theta}$$ where ##cos \, \theta =...

Could someone please help me see where I am going wrong here? During a race between two boats A and B there is a wind of 18 km/h blowing from due north. The resultant velocity if A is 12 km/h on a bearing of 060. Find the direction of the wind relative to A. My reasoning: (Relative to the...

Assume a jet boat or personal water craft (JetSki, etc) has a movable propulsion nozzle. This nozzle can be moved vertically so that the water jet driving the boat forward can be either above the surface or below the surface of the water. Further clarification. You are speeding along on your...

Hi, I am struggling with a calculation. A boat costs x to maintain and I and a friend decide to split the costs 60/40, where I put in 60% of the cost. However, I will have the boat less than my friend, he will have it 3/8 of the time and I will have it 5/8 of the time. So what is my actual...

displacement (x) = 750 m [E] distance = 1100 m I drew a diagram. Now what??

Hi there, I have modeled with MAXSURF a few variations of a prehistoric logboat in order to test a few theories. Now, I am trying to look at resistance-performance over a range of speed. To do so, I need to include a constant drag coefficient without knowing the drag force and velocity (both...

Hi, I'm about to build an autopilot remote for my boat, manual found here: http://www3.sympatico.ca/ericn/Files/Other/DIY Autohelm ST4000.pdf In the scheme I need to use two transisters, a 2N4402 (PNP) and a 2N4400 (NPN) as illustrated here: As I don't have these transisters can I use a...

Momentum of a girl: $$p_{1} = m_{1}v_{1} = 50 * 5 = 250$$ Momentum of an idle boat: $$p_{2} = m_{2}v_{2} = 150 * 0 = 0$$ So if the girl jumps into the boat, the two "systems" connect with each other. The momentum is passed onto the boat (?): $$p_{1} = p_{2}$$ $$m_{1}v_{1} = m_{2}v_{2}$$...

Hey guys, So with some help from classmates I have seen the way I am supposed to approach this problem starting from number 3, which is to use the above equation. But the problem is I have never seen this equation before in class! I don't know what the purpose of the equation is, where it was...

Homework Statement A person of mass ##m## stands at the left end of a boat of mass ##M## and length ##L##. Both the person and the boat are initially at rest. The coefficient of kinetic friction between the boat and the water is ##\mu##. If the person starts moving to the right, what is the...

Homework Statement *I cannot place the original image due to copyright reasons, but the image above is a good alternative. "Wave crests spread out behind a boat as shown above. What do the wave crests indicate about the boat's speed?" It is increasing. It is less than the speed of the water...

A boat is some distance away from a small lighthouse. The angle of elevation from the boat is 9 degrees. If the boat moves forward 20m, the angle is now 12. Assume the lighthouse is at a rightangle to the boat. Calculate the distance from the boat to the top of the lighthouse before and after...

Homework Statement A ferry boat is crossing a river that is 8.5 x 10^2 m wide. The average velocity of the water relative to the shore is 3.8 m/s E and the average velocity of the boat relative to the water is 4.9 m/s S. How long does it take for the boat to get across? Homework EquationsThe...

Two pontoon boat design approach and how to find center of gravity, center of buoyancy, buoyancy, volume of displacement, meta center, meta centric height. I need to know is there a different approach to designing dual hulled boat than a single hulled boat and all the formulas and examples I...

Homework Statement A child in danger of drowning in a river is being carried downstream by a current that has a speed of 2.35km/h. The child is 0.505km from shore and 0.780km upstream of a boat landing when a rescue boat sets out. If the boat proceeds at its maximum speed of 18.8km/h relative...

Homework Statement The water in the river moves southwest (45 degrees south of west) at 4 mi/h. If a motorboat is traveling due east at 15 mi/h relative to the shore, determine the speed of the boat and its heading relative to the moving water. Homework Equations Vector summation The Attempt...

Hello PF, I am a junior in high school who has yet to take physics and is currently in Honors Chem. I recently saw a video on social media, where a group of guys is on a big boat and this one guy was standing relatively close to the bow. And they hit a big wave and he jumps in the air and lands...

A child is in danger of drowning in the river. The river has a current of 2.5 km/hr . The child is 0.6 km from the shore. A rescue boat with speed 20.0 km/hr (with respect to the water) ,located 0.8km downstream, sets off from the shore. What would be the optimum angle (shore -> boat ) to reach...

Homework Statement A 0.14-km wide river flows with a uniform speed of 4.0 m/s toward the east. It takes 20 s for a boat to cross the river to a point directly north of its departure point on the south bank. What is the speed of the boat relative to the water? I'm mostly concerned about the...