Re: Jet drive outboards
[Re: DWC]
#6946152
07/29/20 07:28 AM
07/29/20 07:28 AM
|
Joined: Jun 2007
Posts: 16,150 Tennessee
Scuba1
"color blind Kraut"
|
"color blind Kraut"
Joined: Jun 2007
Posts: 16,150
Tennessee
|
One thing you have to keep in mind is that you loose about 25 to 30% of the power with a jet drive as opposed to having a prop. More at lower speeds as they are not as efficient of transferring engine power into thrust as a prop is. They hate weeds that a prop driven boat will chop up to a certain degree but will clog up the impeller of a jet drive. On the upside, you can go real shallow . per mile you will use more fuel due to the lower efficiency.
There you have it , thats all I know about the basics of jet impeller propulsion.
Let's go Brandon
"Shall not comply" with morons who don't understand "shall not infringe."
|
|
|
Re: Jet drive outboards
[Re: DWC]
#6946179
07/29/20 07:54 AM
07/29/20 07:54 AM
|
Joined: Jun 2007
Posts: 16,150 Tennessee
Scuba1
"color blind Kraut"
|
"color blind Kraut"
Joined: Jun 2007
Posts: 16,150
Tennessee
|
One other thing If you do get stuck and run out of water with a jet powered oat. Call a tow truck and not Sea Tow as a tow boat won't be able to get to you.
Let's go Brandon
"Shall not comply" with morons who don't understand "shall not infringe."
|
|
|
Re: Jet drive outboards
[Re: DWC]
#6946201
07/29/20 08:16 AM
07/29/20 08:16 AM
|
Joined: Dec 2006
Posts: 10,086 ND
MJM
trapper
|
trapper
Joined: Dec 2006
Posts: 10,086
ND
|
I spent way more time in a inboard jet than a out board. They will suck up sand and small gravel, even to the point of doing them in. They do not turn a boat at low RPMs near as well as a prop. They basically don't function at low RPM's.
"Not Really, Not Really" Mark J Monti "MJM you're a jerk."
|
|
|
Re: Jet drive outboards
[Re: Scuba1]
#6946225
07/29/20 08:52 AM
07/29/20 08:52 AM
|
Joined: Jan 2008
Posts: 9,599 Alaska and Washington State
waggler
trapper
|
trapper
Joined: Jan 2008
Posts: 9,599
Alaska and Washington State
|
One thing you have to keep in mind is that you loose about 25 to 30% of the power with a jet drive as opposed to having a prop. More at lower speeds as they are not as efficient of transferring engine power into thrust as a prop is. They hate weeds that a prop driven boat will chop up to a certain degree but will clog up the impeller of a jet drive. On the upside, you can go real shallow . per mile you will use more fuel due to the lower efficiency.
There you have it , thats all I know about the basics of jet impeller propulsion. That about says it. Just a couple of other things; carry a screw driver to pry gravel out of the grate, and a couple of small box end wrenches (7/16 I think) to remove the shoe if you get a big piece of gravel in the pump that you can't get out of the shoe. Someone above mentioned getting stuck after running out of water. What happens is, while you are planing along in shallow water the boat is riding high on a cushion of water. When the water get too shallow and stops you the boat will want to settle back to it's water line, however there is not enough water and you can be a long ways from water that is deep enough to float your boat. The solution to this situation is to carry a come-along, a lot of line, and a Danforth anchor and hope you never have to use the stuff. Don't forget to lube the lower unit daily, and carry a spare impeller and woodruff key with you.
"My life is better than your vacation"
|
|
|
Re: Jet drive outboards
[Re: DWC]
#6946250
07/29/20 09:19 AM
07/29/20 09:19 AM
|
Joined: Feb 2007
Posts: 5,936 New York border
Cragar
trapper
|
trapper
Joined: Feb 2007
Posts: 5,936
New York border
|
Have you considered a aggressive skeg guard on your prop driven engine ? I've run a skeg guard for years , really helps prop protection.
I was launching my boat one day years ago and the fire department was at the ramp with a Zodiac they had just received and were training with. One of the firefighters noticed the weird looking thing on my outboard ( skeg guard ) and asked about it. Now standard equipment on all FD rescue boats in my city.
May or may not fit your application , but just putting it out there to think about.
NRA benefactor member
|
|
|
Re: Jet drive outboards
[Re: DWC]
#6946259
07/29/20 09:33 AM
07/29/20 09:33 AM
|
Oh Snap
Unregistered
|
Oh Snap
Unregistered
|
I have a hydraulic jack plate on my boat. I use it to switch between jet for rivers and prop for lakes and ocean. It works good, I can fine trim out either prop or jet. Waggler is correct about lubing daily but I will add lube at the end of the day, it pushes any water out of the bearings and keeps from rusting. I learned the hard way. Seized up jet unit of course not at the landing!
|
|
|
Re: Jet drive outboards
[Re: Cragar]
#6946271
07/29/20 09:48 AM
07/29/20 09:48 AM
|
Joined: Apr 2011
Posts: 2,606 SE SD
DWC
OP
trapper
|
OP
trapper
Joined: Apr 2011
Posts: 2,606
SE SD
|
Have you considered a aggressive skeg guard on your prop driven engine ? I've run a skeg guard for years , really helps prop protection.
I was launching my boat one day years ago and the fire department was at the ramp with a Zodiac they had just received and were training with. One of the firefighters noticed the weird looking thing on my outboard ( skeg guard ) and asked about it. Now standard equipment on all FD rescue boats in my city.
May or may not fit your application , but just putting it out there to think about. Ive thought about it, but im not sure how thats going to help me get where i wanna go. When its so shallow, if i try planing out, its not that IF im gonna hit, its when, what and how hard. Might save my prop with a guard, but ill still be suckin in sand and crap and be diggin bottom. Ive watched guys with props just throttle down and blow through sandbars, i cant bring myself to treat my stuff that way. Kinda sounds like there isnt a whole lot of good owning one of these. Ive seen a lot of negatives on other sites as well. Maybe i need to skip fishin the river when its low and save up for a surface drive for a few years. Appreciate the feedback.
|
|
|
Re: Jet drive outboards
[Re: The Beav]
#6946335
07/29/20 10:57 AM
07/29/20 10:57 AM
|
Joined: Jan 2007
Posts: 27,454 Georgia
warrior
trapper
|
trapper
Joined: Jan 2007
Posts: 27,454
Georgia
|
I was going to say this or a paddle is the only surefire way to avoid crunching an outboard foot. But considering the best of them have baby's butt smooth bottoms, usually with something owl snot slick painted or attached, I'd cringe ever time it got near gravel or rock.
|
|
|
Re: Jet drive outboards
[Re: warrior]
#6946345
07/29/20 11:08 AM
07/29/20 11:08 AM
|
Joined: Apr 2011
Posts: 2,606 SE SD
DWC
OP
trapper
|
OP
trapper
Joined: Apr 2011
Posts: 2,606
SE SD
|
JMO, but I would not shy away from jets. As a matter of fact if I ever do the river rat thing again I will build a jet rig with tunnel and pods. In my reading there's much said of the negatives and there are a few but further research indicates jets run best on hulls specifically set up just for jets. Hanging a jet off a standard hull is going to give you almost all the possible problems one can have with a jet and it's my belief this is where much of the negative press comes from. Comments from those who have spent the time and money to fine tune their rigs indicate the main intrinsic downsides to be loss of top speed vs prop, loss of max payload vs prop, and lower mpg. All of this is a result of the impellers inability to convert engine hp to equal what a prop can. So if you can live with those three items and are willing to tune your rig I don't see a problem with jets in the right water. Would love the tunnel, just not in the budget. The particular setup im looking at is a 1548 G3 with a Yamaha 40/30 pump. Both the same year. It didnt appear to have a jack on it, and it looks as if G3 paired these up to sell new, at least according to their website from that time frame. Any idea if manufacturers fine tuned these when set up? Ive read that if youre off high by as little as 1/4 inch, you can cause cavitation or be more susceptible to hitting something if too low. Id be very leary of buying a mismatched boat/motor that someone just found used and threw it on a random flatbottom.
|
|
|
Re: Jet drive outboards
[Re: ]
#6946349
07/29/20 11:10 AM
07/29/20 11:10 AM
|
Joined: Jan 2008
Posts: 9,599 Alaska and Washington State
waggler
trapper
|
trapper
Joined: Jan 2008
Posts: 9,599
Alaska and Washington State
|
I have a hydraulic jack plate on my boat. I use it to switch between jet for rivers and prop for lakes and ocean. It works good, I can fine trim out either prop or jet. Waggler is correct about lubing daily but I will add lube at the end of the day, it pushes any water out of the bearings and keeps from rusting. I learned the hard way. Seized up jet unit of course not at the landing! Exactly, I should have specified that.
"My life is better than your vacation"
|
|
|
Re: Jet drive outboards
[Re: waggler]
#6946351
07/29/20 11:13 AM
07/29/20 11:13 AM
|
Joined: Apr 2011
Posts: 2,606 SE SD
DWC
OP
trapper
|
OP
trapper
Joined: Apr 2011
Posts: 2,606
SE SD
|
I have a hydraulic jack plate on my boat. I use it to switch between jet for rivers and prop for lakes and ocean. It works good, I can fine trim out either prop or jet. Waggler is correct about lubing daily but I will add lube at the end of the day, it pushes any water out of the bearings and keeps from rusting. I learned the hard way. Seized up jet unit of course not at the landing! Exactly, I should have specified that. How much of a pain is it to switch the foot with a lower unit?? Might make getting an 1860 with both the answer to all problems!
|
|
|
Re: Jet drive outboards
[Re: DWC]
#6946355
07/29/20 11:17 AM
07/29/20 11:17 AM
|
Joined: Dec 2010
Posts: 11,657 Armpit, ak
Dirt
trapper
|
trapper
Joined: Dec 2010
Posts: 11,657
Armpit, ak
|
The couple rivers i would use this on get down to a foot or foot and a half deep this time every year, and its mainly sand/gravel where it does. I can get through with the prop, but i usually end up takin some paint off and having to try 3-4 different angles to get through. Im sick of having to nearly idle upstream at 2-3 mph, slightly more throtte and it drops the motor down against the current and i hit more stuff. It runs fairly shallow if i get up on plane but id rather not tear off my lower unit. Will the impeller suck up sand from a foot off the bottom or does this only happen in a couple inches of water? Ive read these things steer like crap unless ur runnin hard? Is it tough to slowly position your boat to fish a hole? Don't lock your motor down and you probably won't tear off your lower unit. I've got 28 years running 40 hp Yamaha Jets. 2 strokes and 4 strokes. I've hit so much stuff over the years, I can't believe I haven't ripped the whole Jet off. Destroyed a foot once. No the impeller will not suck up sand off the bottom in a foot of water. If you are moving good you can power thru 10/ 20 foot of sand pumping mud. Sand don't hurt things much other than your water pump impeller and plugging up the water jacket pee hole. Sometimes it will get rocks stuck in your thermostat and you have to clean it. To steer you have to power thru a turn. There is no tiller effect. Slow down in a tight turn and increase power thru the turn. If you power down in a turn, you will not turn and likely crash. I'm a good crasher. Hunker down for them. Crap happens. Just don't sink the boat. I have no idea what your last question means.
Last edited by Dirt; 07/29/20 11:21 AM.
Who is John Galt?
|
|
|
|
|