12v water pump boat design
12v water pump boat design
(OP)
Found a few 12v water pumps around 20 gpm wonder what kind speed i would get from that?
looking for something that would attain speeds of a trolling motor
http://compare.ebay.com/like/390438034571?var=lv&a...
I know ..... I know ...... why not a trolling motor
WHERES THE FUN IN THAT
looking for something that would attain speeds of a trolling motor
http://compare.ebay.com/like/390438034571?var=lv&a...
I know ..... I know ...... why not a trolling motor
WHERES THE FUN IN THAT





RE: 12v water pump boat design
Next problem is estimating the hull drag coefficient...there are some online resources that can help, google "hull drag coefficient" and similar terms.
I'd try just putting different size orifices (jets) on the pump exit to maximize the V*mdot. Could be done pretty easily by experiment, or if you can find a pump curve for your pump, use the BEP.
RE: 12v water pump boat design
Disadvantages of jet pumps include:
- Can be less efficient than a propeller at low speed
- More expensive
- Higher weight in the boat because of entrained water
- Can suffer more easily from cavitation than a conventional propeller
- Can become clogged with debris; e.g., seaweed
http://en.wikipedia.org/wiki/Pump-jetRE: 12v water pump boat design
I'd say pump jets are less likely to foul with debris, since they are more easily protected by a screen, and placement of the intake, from that debris. The entrained water idea might be true for large systems, for a 12v RV pump I think you can safely ignore it - there's more water entrained in the beer cooler than in the plumbing for the pump :).
Finally, for trolling, a jet might be quieter, and probably will be operable in shallower water than the typical trolling motor.
Course, this whole thread might just be a troll...
RE: 12v water pump boat design
RE: 12v water pump boat design
RE: 12v water pump boat design
http://www.proboat.com/a-fix-for-waterjet-fouling....
A trolling motor has about 3-5 HP. The water pump will be a fraction of that. Water jets aren't as efficient as props.
It would probably be easier to use a weedwacker:
http://www.youtube.com/watch?v=RgRiirOQdSQ
RE: 12v water pump boat design
"It appears that you have never been fishing"
Try cutting ~100' of 50 lb test nylon monofilament off the troll motor prop sometime. A suction screen would have blocked it.
Jet boats are used for fishing here all the time, they have their problems, but fouling is not the biggest one.
"A trolling motor has about 3-5 HP. The water pump will be a fraction of that."
So pick a higher power pump.
"Water jets aren't as efficient as props." Bull. Properly designed, they are as efficient, and sometimes more efficient. I will grant you that a typical off-the-shelf RV pump won't be as efficient as a purpose designed troll motor, but that specific comparison doesn't hold. If you are so sure of that fact, tell us all why large ships have been moving more and more to shrouded props (which is all that an axial pump is)?
RE: 12v water pump boat design
RE: 12v water pump boat design
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: 12v water pump boat design
RE: 12v water pump boat design
If that was your point, you made it poorly in earlier posts. I agree with your last post, though.