Adding Third Engine (lower HP) for docking / idle / etc.
03-23-2004, 11:50 PM
#21
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as long as you have a flame arrestor over the carb on the third engine, and the exaust sealed all the way outside the boat, there would be a very marginal increase for the chances of an explosion, especially if you run the blowers like you're supposed to. The only other source of ignition would be from the magneto. If I were to use a generator, I would probabily buy one for marine applications.
8D batteries:
*one mono amp - will be running two JL 12W7 Subs, amp will be doing about 1500 Watts
* one 4 channel amp - will run two 12W3 Subs, as well as all components. Will be doing about 1000 Watts
* Interter - probabily a 1500 watt or 2000 watt inverter - for TV / computer / power tools / whatever.
That'd be a draw of around 210 Amps at 100% volume (asuming 100% efficiency), so I will definetly need the 8D's. I planned to put an isolator on each engine's alternator, and go straight to the second bank of the 8Ds (But that's a whole different story).
If I were to go to 24V, I would have to rig up something with relays to go from series to parallel. I guess it's an option - but I would rather keep it all 12V.
The reason I wanted to "Bore Giant holes" was to avoid the performance loss (minimal, granted) of switchable exaust, and the work involved with mounting it, as well as the thought I would be able to get the boat to plain. Once I realised that 120 or so HP wouldn't do it (now that I think about it, I realise I would need 300+ HP), I became interested in other options. If this type of exaust setup will not be terribly expensive and won't hurt my performance much in the open mode, I might be interested. However, I am not familiar with how they work - would I need to move my current exaust tips ? Would I need new risers / manifolds ? I don't see how it could fit any other way.
As of right now, I am about equally interested in a drop-down style setup like the 33' turbine boat has (for easier steering), and the trim-tab setup. If the silent exaust would be favorable enough, I might go that route instead.
That's a good idea you have with using the scale, I'll try to do it whenever I get a chance, but only to see if it's even possible with trollers - If I went that route I'd put on the biggest setup I could to combat any unforseens - wave action / wind / engine failure / etc.
If it came to it, I could probabily fit two trollers on each of those Kplanes, which would definetly do it (almost 350 LBs from what I've seen for 12V).
On a tangent: What I was previously thinking about instead of a generator was a 8-12 HP manual start engine with a 80-110 Amp marine alternator on it, to charge the 8D's from the Audio usage (and now the trolling usage, I guess). I've seen devices like this before, but never in marine applications. Since you don't like mower engines, what would you suggest ? My primary usage would be lots of DC amps, not AC - I guess I could run the chargers off a generator but my idea seemed simpler.
Thanks,
Paulr
8D batteries:
*one mono amp - will be running two JL 12W7 Subs, amp will be doing about 1500 Watts
* one 4 channel amp - will run two 12W3 Subs, as well as all components. Will be doing about 1000 Watts
* Interter - probabily a 1500 watt or 2000 watt inverter - for TV / computer / power tools / whatever.
That'd be a draw of around 210 Amps at 100% volume (asuming 100% efficiency), so I will definetly need the 8D's. I planned to put an isolator on each engine's alternator, and go straight to the second bank of the 8Ds (But that's a whole different story).
If I were to go to 24V, I would have to rig up something with relays to go from series to parallel. I guess it's an option - but I would rather keep it all 12V.
The reason I wanted to "Bore Giant holes" was to avoid the performance loss (minimal, granted) of switchable exaust, and the work involved with mounting it, as well as the thought I would be able to get the boat to plain. Once I realised that 120 or so HP wouldn't do it (now that I think about it, I realise I would need 300+ HP), I became interested in other options. If this type of exaust setup will not be terribly expensive and won't hurt my performance much in the open mode, I might be interested. However, I am not familiar with how they work - would I need to move my current exaust tips ? Would I need new risers / manifolds ? I don't see how it could fit any other way.
As of right now, I am about equally interested in a drop-down style setup like the 33' turbine boat has (for easier steering), and the trim-tab setup. If the silent exaust would be favorable enough, I might go that route instead.
That's a good idea you have with using the scale, I'll try to do it whenever I get a chance, but only to see if it's even possible with trollers - If I went that route I'd put on the biggest setup I could to combat any unforseens - wave action / wind / engine failure / etc.
If it came to it, I could probabily fit two trollers on each of those Kplanes, which would definetly do it (almost 350 LBs from what I've seen for 12V).
On a tangent: What I was previously thinking about instead of a generator was a 8-12 HP manual start engine with a 80-110 Amp marine alternator on it, to charge the 8D's from the Audio usage (and now the trolling usage, I guess). I've seen devices like this before, but never in marine applications. Since you don't like mower engines, what would you suggest ? My primary usage would be lots of DC amps, not AC - I guess I could run the chargers off a generator but my idea seemed simpler.
Thanks,
Paulr
03-24-2004, 02:59 AM
#22
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how bout this ? If you have a swim Platform you could build a stainless bracket aound the platform ...mount the motor to the bracket and the idea is NOT to be on a plane and the jet is just under the surface ..when you go to sterndrive power the boat is lifted and the jet is out of the water and no drag .....
Last edited by offthefront; 03-24-2004 at 03:38 AM.
03-24-2004, 08:56 AM
#24
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Platinum Member
Switchable exhaust has been around for years. Quite surprised you aren't familiar with it. No real drawbacks Other than an additional 30 pounds for the exhaust yokes (assuming you don't currently have them on your boat) and maybe 5 more for the actuator pump.
You're still not hearing me on the USCG thing. (and I like lawnmower engines just fine on lawnmowers). If you wanted to use one in the boat, you would need to:
#1: have a separate fuel pump for it cause fuel will not gravity flow in a boat. The fuel pump would need to be either a small marine electric pump or a jetski style diaphragm pump.
#2: The carb(s) on the motor would need to have a closed venting loop put on it to keep sticking floats from drooling gas into your bilge.
#3: flame arrestor.
#4: if it had points (which they don't anymore) then you'd have to change it to cdi.
#5: you have to remove any of the factory "kill switches" that short to ground via open (non marine) switches and run a remote kill switch with the proper switch (out of the engine compartment).
#6: You'd have to fabricate your own water cooled and water jacketed exhaust system for it, because no exposed item can be over (is it 450 degrees?) a certain heat level in an enclosed compartment to avoid vapor combustion.
#7: You'd have to run for sure with the blower on at all times
#8: if it's a air cooled motor, you'd have to run with the hatch open, which makes it louder than most of the other choices mentioned (and definitely louder than underwater exhausts on your main engines).
Your expected use of the inverter is appropriate. Just checking since I've heard people talk about installing an inverter to power their battery charger before... (not suggesting you would make that suggestion, but just checking anyhow).
24 volt switching can be done.
Only one battery is permanently attached to ground.
In 24 volt mode, one battery still supplies 12 volts to whatever needs it, while the other is plumbed in series (with its "-" pole removed from the grounding system) to shoot 24 to the trollers. To be honest, both batteries can still provide 12 volts to other accessories at the same time, but they must be feeding two separate unconnected systems- so it is easier to just drop to one feeding 12v and the other used to provide 24.
Most portable generators (Honda included) have a DC outlet on them. It is normally, though, a smaller output (8 amps @ 12vdc in the case of the Honda). Two inexpensive chargers can be used far more effectively.
If you ran 2 trollers wide open (50 amps x2 @ 24v), you would suck your 8D's empty in a little over 2 hours.
You don't like the idea of an outboard on the back, although a Honda 9.9 weighs 115 pounds and a Honda 20 weighs 135 pounds. Can't say that I blame you, but they are by FAR the most sensible addition in the way of adding additional powerplants. (a 2hp weighs 30 pounds - and is the equivalent of FOUR trollers, and a 20 would be the equivalent of FORTY trollers if the rule of thumb I found is correct).
Do yourself a BIIIIIIGGG favor, and look into switchable exhaust.
http://www.rexmar.com/page234.html
http://www.marineparts.com/partspage...a-Gil/GIL6.htm
http://www.marineparts.com/partspage...omparisons.htm
http://www.corsaperf.com/mbrochure3.htm
quiet like a baby.
You're still not hearing me on the USCG thing. (and I like lawnmower engines just fine on lawnmowers). If you wanted to use one in the boat, you would need to:
#1: have a separate fuel pump for it cause fuel will not gravity flow in a boat. The fuel pump would need to be either a small marine electric pump or a jetski style diaphragm pump.
#2: The carb(s) on the motor would need to have a closed venting loop put on it to keep sticking floats from drooling gas into your bilge.
#3: flame arrestor.
#4: if it had points (which they don't anymore) then you'd have to change it to cdi.
#5: you have to remove any of the factory "kill switches" that short to ground via open (non marine) switches and run a remote kill switch with the proper switch (out of the engine compartment).
#6: You'd have to fabricate your own water cooled and water jacketed exhaust system for it, because no exposed item can be over (is it 450 degrees?) a certain heat level in an enclosed compartment to avoid vapor combustion.
#7: You'd have to run for sure with the blower on at all times
#8: if it's a air cooled motor, you'd have to run with the hatch open, which makes it louder than most of the other choices mentioned (and definitely louder than underwater exhausts on your main engines).
Your expected use of the inverter is appropriate. Just checking since I've heard people talk about installing an inverter to power their battery charger before... (not suggesting you would make that suggestion, but just checking anyhow).
24 volt switching can be done.
Only one battery is permanently attached to ground.
In 24 volt mode, one battery still supplies 12 volts to whatever needs it, while the other is plumbed in series (with its "-" pole removed from the grounding system) to shoot 24 to the trollers. To be honest, both batteries can still provide 12 volts to other accessories at the same time, but they must be feeding two separate unconnected systems- so it is easier to just drop to one feeding 12v and the other used to provide 24.
Most portable generators (Honda included) have a DC outlet on them. It is normally, though, a smaller output (8 amps @ 12vdc in the case of the Honda). Two inexpensive chargers can be used far more effectively.
If you ran 2 trollers wide open (50 amps x2 @ 24v), you would suck your 8D's empty in a little over 2 hours.
You don't like the idea of an outboard on the back, although a Honda 9.9 weighs 115 pounds and a Honda 20 weighs 135 pounds. Can't say that I blame you, but they are by FAR the most sensible addition in the way of adding additional powerplants. (a 2hp weighs 30 pounds - and is the equivalent of FOUR trollers, and a 20 would be the equivalent of FORTY trollers if the rule of thumb I found is correct).
Do yourself a BIIIIIIGGG favor, and look into switchable exhaust.
http://www.rexmar.com/page234.html
http://www.marineparts.com/partspage...a-Gil/GIL6.htm
http://www.marineparts.com/partspage...omparisons.htm
http://www.corsaperf.com/mbrochure3.htm
quiet like a baby.
03-24-2004, 09:12 AM
#25
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Location: ST. Louis, MO, USA
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Simple is ALWAYS better on a boat. If the issue is noise, get a silent choice system.
If you NEED another motor, get a small O/B, mount it on a bracket above the keel so there's no drag when you're running on the IOs. Tie it into your existing steering.
BTW, You're going to need a lot of batteries to move an 8000lb boat for 20+ minutes on an electric trolling motor.
Gary
If you NEED another motor, get a small O/B, mount it on a bracket above the keel so there's no drag when you're running on the IOs. Tie it into your existing steering.
BTW, You're going to need a lot of batteries to move an 8000lb boat for 20+ minutes on an electric trolling motor.
Gary
03-24-2004, 09:41 AM
#26
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Are the stern mounted thrusters (like bow thrusters) much different from trolling motors? Would they be an option here if they were oriented fore and aft instead of sideways?
03-24-2004, 09:47 AM
#27
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Originally posted by mcollinstn
Another option may be to use a couple of cavitation plate mounted trolling motors and carry a Honda EU200i generator to not only keep the batteries charged for the trollers, but to run a carryon A/C while you cruise slowly in the searing heat. Those boogers are MEGA QUIET.
Another option may be to use a couple of cavitation plate mounted trolling motors and carry a Honda EU200i generator to not only keep the batteries charged for the trollers, but to run a carryon A/C while you cruise slowly in the searing heat. Those boogers are MEGA QUIET.
, I think I musta had a lot of (to much) time on my hands the summer I tried that 
03-24-2004, 09:48 AM
#28
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I know how it is when you get an idea for doing something a certain way, when an easier solution is obvious. You're just looking for a challenge aren't you?
For less than the cost and complexity of adding a silent drive, you could design or source a better silent choice system. Formula had the right idea with their silent thunder swim platforms with integral exhaust. Nobody in their right mind would complain about the noise from that system. You could build something similar to fit under your swim platform that could work even better. Do it right and you will have a product to sell.
For less than the cost and complexity of adding a silent drive, you could design or source a better silent choice system. Formula had the right idea with their silent thunder swim platforms with integral exhaust. Nobody in their right mind would complain about the noise from that system. You could build something similar to fit under your swim platform that could work even better. Do it right and you will have a product to sell.
03-24-2004, 09:53 AM
#30
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Posts: n/a
P.S. I only used them as steering around the docks so just hooked them up to the house batteries avoiding the generator issue and this was fine cause they were only used for a couple minutes or so while docking. Control was via a couple DPDT toggle switches on the dash driving 3 relays which switched /reversed the power to the actual motors, required as the curretn involved is signifigant 30-50 amps depending on the motors.
