Dream Engines

for traveling inland waterway's we use http://www.noordersoft.com/indexen.html cost some 250? though.

 

THANKS Portager ! Just what I needed. One problem,I cant get the attached fill to down load. Any suggestions?

 

selene 430hp

My guess John is 12kts is well above hull speed for the WL on the Selene 53
hence the massive overpower. you mentoned 160 hp for like vessels, This seems right on the the line for a realistic trawler with adequate hp ratings. A boat simular to the selene should top out at 9.5-10 kts with a realistic cruise of 8-8.5. It takes gobs of HP to overcome hull speed in a displacement hull. I noticed she is only tanked for 1050 gal us too, At 12 knots that thing is not going very far! I bet that Cummins burns 18 or more gallons an hour @ 12 kts
1050 gals / 18gph=58.33 hours @ 12kt = 700 nm's!!!!! hardly enough fuel to get out of site let alone cross an ocean. Of course throttle down to a reasonable 8.5 or so and economy improves greatly. In my opinion she is grossly overpowered to get that 12 knot figure to show up in the sales propaganda. A vessel of the size your thinking should only require 1/3rd of that HP.
I dont have Luggers lit sheets here with me but they have a good web site showing all the ratings and available engines. The one I like is the 668D "I think"
For your wing engine you might consider a northern lights gen set with a PTO hydraulic pump for your get home. A 12K maybe...... Dont forget to keep that 12K under at least 1/2 load or the engine life will be shortned "diesels need to work" consider another smaller 5K for your lighter needs while riding the hook watching the idiot box!
good luck 8Knots

 

As 8knots points out, 12.5 knots is above what is generally considered hull speed for displacement hulls, i.e. a SL (speed/length^.5) of ~1.34, however since the Selene’s all use semi-displacement hulls they can exceed “hull speed” and sort of semi-plane, but it takes a lot more power. Each person needs to decide how fast they really want to go and they should understand the cost of going faster. In the case of the Selene 57, to achieve a SL of 1.34 (speed of 9.77 knots) requires SHP = LB/(10.665 / (Speed / WL^1/2))^3 = 88300/(10.665/1.34)^3 = 175 HP. To achieve a SL of 1.6 (speed of 11.6 knots) requires 298 HP. Thus, to achieve an 18.6% speed increase requires 70% more power and will consume 70% more fuel. In addition, if you select the 300 HP engine, but spent 95% of the time cruising at 9.75 knots (or less) then your are under-loading your engine most of the time (unless you use the controllable pitch propeller that you already indicated your planned on doing).

The Selene 57 is equipped standard with a Cummins 6CTA8.3M3. I can’t find specifications for the 6CTA8.3M3, but the 6CTA8.3M1 http://www.gce.cummins.com/mce/mce_specsheets/3885114_0503.pdf has a marine continuous rating of 250 BHP at the crank shaft. Using a transmission efficiency of 98% and Dave Gerr’s equation, SL ratio = 10.665 / (LB/SHP)^1/3 SL = 10.665 / (88300/.98*250)^1/3 = 1.5 or a speed of 10.96 (note this speed is with no winds, waves or currents, i.e. the proverbial mill-pond rating (MPR)). Thus: I conclude that the Selene 57 can not maintain 12.5 knots for longer than 2 hours out of every 24 hour period.

Now for the Lugger’s and starting with the LP668D that 8knots likes. The LP668D http://www.northern-lights.com/LP668D.shtml is a naturally aspirated diesel with a continuous rating of 105 HP. This provides a SL of 1.12 which equates to a speed of 8.2 knots MPR. Although this is greater than 8 knots, I think it is a little marginal when you consider wind, waves and current. For comparison, this engine weighs 1194 lbs (542 kg) with Heat Exchanger, without gear compared to the Cummins at 1,924 lb Dry Weight, with heat exchanger cooling and MG507A marine gear.

If 8.2 knots isn’t adequate, the next step up is the LP668T http://www.northern-lights.com/LP668T.shtml which is a turbocharged version of the LP668D. The LP668D has a continuous rating is 140 HP, which provides a SL of 1.23 and a speed of 9 knots MPR.

If 9 knots isn’t enough, the next step up is the Lugger L6108A2 http://www.northern-lights.com/L6108A2.shtml which is turbocharged and aftercooled 6 cylinder, with replaceable dry cylinder liners. The L6108A2 has a continuous duty rating of 300 HP @ 2300 RPM, which provides a SL of 1.596 and a speed of 11.64 knots MPR.

If you don’t like the dry cylinder liners, you could go to the L6125A http://www.northern-lights.com/L6125A.shtml which incorporates an all-iron combustion design with wet liners and nodular iron pistons. The L6125A has a continuous duty rating of 325 HP, which provides a SL of 1.639 and a speed of 11.96 knots MPR. Incidentally, the L6125A is based on the same block as the John Deere 6125AFM that I recommended before. For comparison, this engine weighs 2400 lbs (1090 kg).

Gotta love a straight man! This is the reason for using the hydraulic generator see http://boatdesign.net/forums/showthread.php?t=3143 . Since the engine speed is independent of the generator speed, the engine speed can be adjusted to the load (next lesson after hydraulics 101 will be engine speed control using pyrometers), so the engine is always at the proper speed for the power load. I think the hydraulic generator is a far better solution than a second generator.

Regards;
Mike Schooley

 

Mike, As allways you are a wealth of information. My mistake on the Selene's being semi-disp. I did not dig deep enough and that HP rating is reasonable for that sort of hull style. I still would consider her a "large coastal cruiser" she is tanked way too small and is based on pleasure ratings on the main engine.
Mike. On your venture to use inverters do a Google for "TRACE INVERTERS"
they are a really cool set up if your serious about using inverters. I had at one time considered using them for my home. They have a 4k unit that is top shelf as far as features. I have seen them in photos in engine rooms.
have good one 8

 

HERE WE GO MIKE.
http://www.e-marine-inc.com/products/inverters/trace.html
http://www.scsolar.com/Inverters_Xantrex_Trace.html
8

 

Thanks 8;

I was focused on the Victron Phoenix inverter and inverter/charger http://www.victronenergy.com/ , but the Xantrex (Xantrex bought Trace) model you recommended looks better http://www.victronenergy.com/ . I see I am going to have to study the specs until my vision gets blurry and then flip a coin.

Actually I know an engineer that used to work for Xantrex and I know he has had experience with the Victron, so I ask him which is better.

Thanks again;
Mike Schooley

 

Just to throw a little spanner in the works....
The April edition of Passagemaker has a letter to the editor regarding the Selene line of vessels (which in turn refers to a quite lengthy article published in the preceeding issue). The editors response goes like this...

(of course, we know that deeper sections won't increase displacement, it will just allow the addition of more weight without altering the boats profile...)

So it may be more a case of piling more and more power into a displacement hull in order to achieve speeds that the market supposedly deems as necessary....

 

My thanks to 8 Knots Portager and Willallison for all the good information. Some of it is a little over my head so I will re-ask a couple of my questions even though I'm sure you've already answered them. The use of a side engine will be to cruise at 2-3 knots on the rivers of Europe. The main engine will be for cruising on an average of 10 knots. My thinking is that since diesels like to work under load using the L6125A 325 HP at 2-3 knots would be detramental to the engine by causing carboning up. Since the side engine will be used to propel a Selene 53 I assumed I needed a 40-50 HP to run at 2-3 knots. My first questions is - Is this correct thinking? If so, what engine would you recommend at what HP. Next, since I intend to use a controllable variable prop to keep the engine under proper load during variable conditions, what prop and what electronic controls to control the prop would you recommend. Portager recommended a hydraulic generator as a better solution than a second generator. Could you go into more detail with the specific model or brand you have in mind. Any other suggestions as far as hydraulics or alternators - please throw them into the mix. I intend to get hydraulic stabilizers and if possible hydraulic bow and stern thrusters. Just thought you might need to know in case it might have any bearing on your suggestions. Lastly, regarding the prop - if no one has any specific suggestions on the prop or how to control the prop perhaps someone has a web site with a dealer or a dealer in the Seattle, Washington area who could point me in the right direction. Thanks again.I forgot to mention that I found a web site "Selene & Solo Trawlers Voyager Club". Owners claim 6gph at 10 knots average with the Selene 53. Seems to good to be true with such large engine.

 

John;

If you really want to only go 2 to 3 knots on the auxiliary, that would be a SL of 0.411 and the power required would be 88600/(10.665/0.411)^3 = 5.07 HP. I think it would be a mistake to size your auxilary that low, because if the main engine fails at sea, you need the auxiliary to get you home and 3 knots would barely buck the wind and waves. I’d say the minimum should be 5 knots, which would require 23.5 HP at the propeller. Since the hydraulic motor will upstream of the transmission, you will have about a 98% transmission efficiency and 85% hydraulic power transmission efficiency so you would need 23.5/.98/.85 = 28.2 HP at the auxiliary shaft. To do 6 knots would require 48.74 HP. Throttling a 28 or even a 50 HP auxiliary down to 5 HP wouldn’t be too difficult, but running a 250 HP main at 5 HP all day would probably be bad. I’ll wait to make suggestions until you decide what HP you want.

Probably the most economical controllable pitch propeller option in this power range is the SABB (not SAAB) in Norway http://www.sabb.no/ but you might have to go to Hundested www.hundestedpropeller.dk . The SABB web site won’t do you much good unless you read Norwegian, but they do provide their phone # and email address. Try emailing them at firmapost@sabb.no and ask for a dealer in your area.

The SABB controllable pitch propellers have a shaft that runs through the center of the drive shaft to the propeller. Pushing on the rod increases pitch and pulling (or visa versa) decreases pitch. The propeller control rod is usually activated by a hydraulic cylinder which is tied to a throttle control on the bridge. To control the speed of the engine you monitor pyrometers in the exhaust manifold. The goal is to keep the pyrometers above 850 degrees F. I’m looking for a computer controller that will monitor three pyrometers and automate the throttle setting.

On the hydraulic generator, lets start with complete systems even though that is probable not where you’ll end up, it makes it easier to discuss. A good hydraulic generator system is made by Fabco http://www.fabcopower.com/firepowermodular.html . This is a complete hydraulic generator system (except for the engine) which can be connected to a power take-off (PTO) shaft. I’ll answer more of your questions when I get time. I was planning to write a description of hydraulic system and recommend some components, but I spent my time writing this response instead.

If your objective is to cruise canals in Europe, then I suggest you might want to select a boat with a lower profile. Perhaps you could start a new thread requesting suggestions of boats for cruising European canals. Also state if you plan to purchase your boat here and cross the Atlantic, since that will also drive your selection.

Regards;
Mike Schooley

 

Will, I have that article your talking about, maybe thats where I got the full displacement thinking from. I have way to many hull swimming around in my noggin for any normal person to deal with
Mike, What you need for your pyro/prop controls is a unit from Watlow or Omron. Temprature controllers are digital units that read many different types of thermocouples, "K" being the most popular. I have 2 watlow units for my foundry, size about 1" x 1.5" x 4" deep with 3 buttons on the face. One for menu & 2 for up down. Most have red or green led digital readouts.
I only use them for temp readouts in my melts. but they have the ability to monitor 2 thermocoulpes and have an internal switching relay that can open and close a circuit at any user determined point. You can also select a "threshold" for the breakpoint say +- 50deg or whatever. all this is done through the menu built into the unit. The catch is you will need another relay with an input voltage of 5v dc and whatever you require on the secondary side. The output of the watlow is 5v dc, if you pull a bigger load it will smoke it. I think the retail on most is $350-700 depending on how many bells they have. I bought mine on Ebay for $110 for the pair. I had my thermocouple and ss probe made by a company "the name eludes me now"
here in the states. I will get you the web site so you can get a catalog. I must say they are the best company I have EVER dealt with. You will be pleased with what they have to offer.
John, I'm not sure if I know what I am talking about here but I have heard of marine transmissions that have a "trolling valve" controlled at the helm that allows you to spool up the engine say 1200 rpm with reduced output to the shaft. "A low range if you will" This is used for close quarters work like getting out of the marina or trolling at slow speed while sport fishing.
mike is dead right about needing about 5 knots speed from your wing engine. 2-3 kts will get you no-where in even a light breeze or bucking a tide. I would do all your math to reflect no less that 5 kts performance from your wing.
Gotta get to work Have a good one!
8Knots

 

Here is an article that might answer some of your questions on controllable pitch propellers http://www.kastenmarine.com/CPprops.htm .

For the hydraulics, I could make recommendations, but I think you would get better advice from an engineer with more hudraulics experience and someone that can produce CAD drawings and recommend components. I am currently thinking of using the experts at http://www.hydraulicsupermarket.com/consult.html to design my system. They also have a great technical library http://www.hydraulicsupermarket.com/technical.html and product library http://www.hydraulicsupermarket.com/products.html .

To answer one of your questions that I shipped over, the hydraulics should be water cooled. You can choose sea water or fresh water depending on your design. In my case, since I’ll have an aluminum hull, I’ll be conducting the heat through the hull, i.e. keel cooler.

Another innovation (or what I believe to be an innovation) that you might be interested in, is my bow and stern thrusters. Since I’m originally a rocket propulsion engineer, I plan to use water nozzles (water rockets) and a high pressure pump for my bow and stern thrusters. The system would consist of a centripetal pump (powered by a hydraulic motor) which would feed a trio of nozzles in the bow and stern through a large pipe. The nozzles would be activated by a solenoid valves. The nozzles would be located below the waterline to avoid spraying adjacent boats and making a lot of noise. Each trio of nozzles would be arranged in a “T”, pointing to port, starboard and either forward or aft. This would provide the equivalent of a bow thruster and a stern thruster plus forward and aft thrusters.

The advantage of the nozzle thrusters is there is no exposed propeller so for shallow water or areas where there are lines, sea weed or debris in the water you are less likely to damage or entangle the prop. You also have an independent propulsion and steering system, so if the main shaft/prop or rudder is damaged you have back-up propulsion/steering and it should make the boat extremely maneuverable. Another more subtle advantage is; nozzles are effective regardless of boat speed, where as for conventional bow thrusters, effectiveness drops off as speed increases because the flow over the hull can not be turned to go through the bow thruster without inducing cavitations.

The disadvantage is, for high efficiency you want to use high flow rates and a low pressure differential, i.e. more like a jet drive or conventional bow thrusters, however to keep the pluming and the nozzles reasonable small, you want to use high pressure and lower flow rates. Therefore, the propulsive efficiency of nozzle thrusters (operating in the 100 to 200 psi range) is about half that of the propeller, so it takes twice as much power to do the same job. Since the nozzles are less efficient, you do not want to use them for primary propulsion, but for short periods the lower efficiency is tolerable.

In your case; if you have a ~50 HP auxiliary, you could do 6 knots when driving the main propeller. When applying that power to the water pump and using the stern nozzle, you would get the effect of a 25 HP drive which would provide 5 knots speed.

Since the auxiliary will also power the generator and alternators, I’d recommend you add about a 10 to 15 HP margin so you can use those systems and provide back-up propulsion simultaneously. This would mean you want about a 65 HP auxiliary. You would also like to keep the maximum engine RPM about the same as your main engine so you can use the same pump/motor on each engine and have commonality of spares. Staying with the Lugger engines, you could use the L984D. This engine is rated at 70 HP at maximum speed of 2500 RPM, but max continuous speed is 2200 (gotta love those marketing guys) which nearly matches the 2100 RPM continuous duty speed of the L6125A. At 2200 RPM the L984D produces 64 HP which should meet your requirements.

It occurs to me, that if you keep taking my advice, your boat will resemble an overgrown version of Portager .

Regards;
Mike Schooley

 

Mike. I had no idea we were dealing with a real by gummy "rocket scientist"
It must have been a fun field to work in!
8

 

Thanks! While we are on the subject of generating power,there seems to be some different ideas on how to do it. I will be at anchor for some periods of time,it would seem that if my batteries were recharged from a seperate gen I would'nt have to run the engines.I would like to charge batteries and get general power from the gen,then, I would like to charge batteries when either engine is running besides giving me general power. I thought that a switching system in the pilot house might be the simpliest system, but I'am open to ideas from "THE BRAIN TRUST'.Next is the proplem of getting power while at dock,in europe and the USA.I'll have to have two inverters,one for europe,one for USA. Next,how about a couple of solar panels, total maybe 750 watt, not really sure about the switching or setup. I did see last summer a boat that had two panels on the flyingbridge,they were put out when needed then put away,seemed to work well. the owner told me that it supplied all their power needs.Lastly are we all in agreement on the 65 HP side engine? Sounds good to me!

 

John;

I think I’ve mentioned my approach to generating power before, but I’ll review the basics and then discuss power management.

In the old days, before inverters reached their current level of maturity, the only option was to get an AC generator and run it when ever you needed power. As inverters improved, boaters started installing battery banks and recharging the batteries off the generator. This provided the ability to have periods of piece and quiet with electrical power available. By installing a larger battery bank, you can extend the period of piece and quiet, but the noise (recharge) period also increases. Installing a larger battery charger reduces the charging time, but the minimum recharging time is limited by the maximum charge rate of the batteries. By using AGM batteries, which can be recharged faster, the recharge period can be reduced to the limit of the charger.

As a practicing systems engineer and systems architect, I submit that the basic architecture of this approach is flawed. It does not make sense to run a diesel engine and force it to run at a specific regardless of load to produce AC power to power a battery charger which provides DC power to recharge the batteries. It makes more sense to produce DC power directly and eliminate a primary bottle neck in the system, i.e. the AC battery charger. The AC battery charger isn’t totally eliminated since it is still used when using shore power.

Since there are still some systems onboard, like air conditioning systems, which require AC power, I believe a hybrid AC/DC system is optimum. I recommend getting everything on DC that you can and provide a small AC generator for what is left. Then use engine driven alternators to produce DC power and size the system capacity or recharge the battery bank in the minimum advisable time. Further, I believe that if you are going to have hydraulics onboard, then it makes very good sense to use hydraulics to run the generator and alternators since this allows the engine speed to be independent of the generator.

For the DC system, I prefer 24 volt systems. My research indicates that almost everything you’ll need onboard that runs on DC power can be operated on 24 volts. Additionally, 24 volt systems reduce current levels and which reduces wiring weight. There are a few things that still need 12 VDC, but they can be run on a 24 VDC to 12 VDC converter.

I would use the Balmar 98-24-220-BL http://www.balmar.net/98dimensions.htm . This alternator will produce 200 amps at 24 volts when turning 3,600 RPM, which is an easily achievable speed with hydraulics motors. At full load, the alternator will require about 7.5 HP (assuming 85% efficiency).

Sizing a hydraulic motor to drive this alternator goes as follows:

Using the motor displacement equation from http://www.hydraulicsupermarket.com/upload/db_documents_doc_9.pdf

Vm = Tm x 75.4 / Delta_p x etahm.m

Where:
Vm = moto displacement (in^3/rev)
Tm = Motor Torque (ft lbs)
Delta_p = pressure drop across motor
etahm.m = motor hydraulic/mechanical efficiency

Calculating the required torque from the power demand:

Torque (lb.ft) = Power (HP) x 5252 / Speed (RPM) = 7.5 x 5252 / 3600 = 10.94 lb.ft

Assuming, for now, that we set our system operating pressure at 2800 psi and allowing for 800 psi of pressure drop in the system, we will have 2000 psi of pressure drop across the motor.

Vm = 10.94 x 75.2 / ( 2000 x .9 ) = 0.457 (in^3/rev) minimum motor displacement

As an example of a gear pump/motor to run the alternator, I went to Grainger.com and found a motor made by JOHN S. BARNES rated at Flow 0.8 GPM @ 3600 RPM/1000 PSI, Maximum Continuous Pressure 3000 PSI, Maximum Speed 5000 RPM, cost = $113.60 http://www.grainger.com/Grainger/productdetail.jsp?xi=xi&ItemId=1611769937&ccitem . You will also need a shaft coupling such as the Lovejoy Jaw Coupling Hubs http://www.grainger.com/Grainger/productdetail.jsp?ItemKey=3KA98 at $39.90 in Stainless Steel, a custom motor mounting brackets similar to http://www.grainger.com/Grainger/productdetail.jsp?xi=xi&ItemId=1611664595&ccitem= but custom designed and fabricated to adapt the hydraulic motor to the alternator assume $100 and two high pressure hydraulic hoses http://www.grainger.com/Grainger/productdetail.jsp?xi=xi&ItemId=1611763846&ccitem= $13.60 each. Total cost of the hydraulic drive $289.70.

With belt drive the Balmar alternator required two ½” drive belts, which produce significant side loads (usually) on the water pump bearings, which reduces water pump life and the belts require periodic maintenance and replacement. If you have hydraulics onboard, the added cost of running the alternator from hydraulics is only $280.70 and the additional maintenance is just replacing hoses periodically (since you already need to service the hydraulics anyway). An additional benefit is the alternator speed is independent of engine speed, so the alternator can produce full power even when the engine is just idling.

At idle, i.e. 800 RPM, the L984D produces 25 HP, so a single alternator would only provide a 30% load, therefore I would use two alternators and combine them using the Balmar Centerfielder http://www.balmar.net/PDF/Centerfielder.pdf . This will provide a 60% load for the auxiliary at idle, even when nothing else is running and it will provide up to 400 amps at 24 VDC or 9.6 kW of DC power.

I think the combination of good sound proofing and the engines low speed operation will provide an extremely quiet generator capability.

With this much current available it is vital to properly size your battery bank. Flooded lead acid batteries should not be recharged at greater than 25% of the battery bank capacity, so your battery bank should be >1600 amp-hours. Assuming you only use 50% depth of discharge and you only bulk charge while on the generator, your usable capacity is 1600*(.8-.5) = 480 amp-hours and recharge time will be 1 hour 12 min.

If you use absorbent glass matt batteries you can recharge at 100%, so your minimum battery bank capacity is >400 amp-hours. If you use Hawker Genesis batteries you can use 100% depth of discharge and bulk charging stops at 90% so the usable capacity is 90%. To get the same usable capacity with AGM batteries you would need 533 amp-hour total capacity and recharge time would be 1 hour and 12 min.

Regards;
Mike Schooley