ePropulsion Pod Drive

[Crash]

Sure but why give up on extra stern handling by not putting the prop closer to the rudder? Its a small boat so the difference between 'kicking the stern' and throwing a line or what not might be somewhat academic. Nevertheless, looks like the fellow owner who Bull consulted with opted to put the prop further aft and below the 'mystery compartment'. Also, as far as drilling holes, a small hole in the bulkhead and you can easily put the battery closer to centre in the 'storage area', if desired.

BTW, you can turn an outboard but you can't turn a fixed prop. Luckily for me I swore off auxiliary outboards on a sailboat 40 years ago so its a distant never to be revisited memory.

Fufkin, an honest question here.  How many boats have you owned with a sail drive (farther from rudder) vs conventional shaft (closer to rudder)?  I’ve owned 1 saildrive (J/109) and 4 conventional (all 30 ft racer/cruisers) and the J/109 handled better/more nimbly than any of the conv boats.  You could kick the stern as easily & effectively as any of the others. Might have had to use a touch more throttle, but lack wash over the rudder was never an issue.  Maybe part of that was due to the J’s more modern/deeper shape compared to the “mid 80’s” rudders on all the other boats.  I agree you couldn’t “walk the stern” using prop walk.  But then again, you could back much more easily, so to me it’s win for the more forward location.  In 40+ years of boating, there’s been only 1 time I’ve had to spin a boat 180 degrees using reverse prop walk and forward stern kick.

My experience says go with the more forward location (centered weight, less drag, no loss in maneuvering forward, gain in backing), so I’m curious about what in your experience says differently?

Crash

 

[Bull City]

Nevertheless, looks like the fellow owner who Bull consulted with opted to put the prop further aft and below the 'mystery compartment'. 

Perhaps this wasn't clear, the Swiss fellow's hatch was over the forward part of the cockpit, right over the space I plan to locate the pod and battery. His pod is just aft of the keel.

 

[TwoLegged]

Compared with the outboard hanging off the stern, surely any inboard ahead of the rudder will be a step up several gears in handling

Sure but why give up on extra stern handling by not putting the prop closer to the rudder? Its a small boat so the difference between 'kicking the stern' and throwing a line or what not might be somewhat academic. Nevertheless, looks like the fellow owner who Bull consulted with opted to put the prop further aft and below the 'mystery compartment'. Also, as far as drilling holes, a small hole in the bulkhead and you can easily put the battery closer to centre in the 'storage area', if desired.

Why? Because the fwd mount gives better weight location, easier and less destructive installation, and easier maintenance ... and the possible gain in manoeuvrability will be small and un-needed.  This is a low freeboard light wee boat sailing in a light air lake, where its sailing abilities are paramount.  It is not a 10-ton high windage hull which needs to maximise its chances of berthing in high winds after a hard passage.

BTW, you can turn an outboard but you can't turn a fixed prop.

Bull's outboard was on the transom, about 5 or 6 feet behind the helmsman's position. I doubt there was much scope for turning the outboard while manoeuvring, because abandoning the helm to jump up on the lazarette and manipulate the outboard would create a pile of new problems .

 

[weightless]

View attachment 417428

Looks nice! Kinda hard to tell on my small screen but it looks like he has a folding prop. Maybe even takes commercially available props? That would add value for me.

 

[fufkin]

Fufkin, an honest question here.  How many boats have you owned with a sail drive (farther from rudder) vs conventional shaft (closer to rudder)?  I’ve owned 1 saildrive (J/109) and 4 conventional (all 30 ft racer/cruisers) and the J/109 handled better/more nimbly than any of the conv boats.  You could kick the stern as easily & effectively as any of the others. Might have had to use a touch more throttle, but lack wash over the rudder was never an issue.  Maybe part of that was due to the J’s more modern/deeper shape compared to the “mid 80’s” rudders on all the other boats.  I agree you couldn’t “walk the stern” using prop walk.  But then again, you could back much more easily, so to me it’s win for the more forward location.  In 40+ years of boating, there’s been only 1 time I’ve had to spin a boat 180 degrees using reverse prop walk and forward stern kick.

My experience says go with the more forward location (centered weight, less drag, no loss in maneuvering forward, gain in backing), so I’m curious about what in your experience says differently?

Crash

Crash, sure I'll do my best.

First, as far as ownership, I've owned the same Frers designed 31 footer with a sail drive closer to the rudder for the last 30 plus years so maybe I'm biased. I found the sweet spot for my type of sailing and location, and the slip is worth more than the boat so I have zero plans to switch things up anytime soon. 

I have had the chance to helm a variety of other peoples boats as well as charter a few on my own, so I'll try to give a brief rundown of some different types of set ups and how they've performed under power in tight quarters. I'm surprised you've only had to 180/360 a boat just once. I find it comes into play quite regularly...my gas and pump out is at the end of the fairway, in tight quarters, with a bridge to catch your mast if you happen to fuck things up. A larger boat might back in.

1 I'll start with a cheat. 47 foot catamaran, twin engines, zero requirement to really even use the rudders to spin the boat, flow over rudder less of a requirement for steerage. Easiest boat to manoeuvre under tight quarters.

Ok lets cut to the chase and look at a few monohulls...

2. How bout a full keeled Cape Dory where the prop is right up against the rudder. My experience being more with fin keel spade rudder type of underbodies, I found it difficult to ''spin' this boat, especially against a crosswind coming down the fairway. After trying a few times, aborting, then finally making the back out and turn up into the headwind, I asked my brother in law who had just inherited the boat(who doesn't sail but has a guy at his office to take it out with him), 'let me guess, the guy you usually sail with backs it out'. His grin said it all. Once out there I figured that was a good learning opportunity so tried to teach him the 'kick the stern and walk the prop' routine. I found that the full keel over road the ability to do this any way as effectively as a a fin keel an spade rudder set up, so prop location re the rudder made no difference.

3. Let's go to the other extreme. At one point I had a lot of helm time on Farr 40s, and especially under power as we were commissioning and setting up two of them for a regatta, and my buddy who was the white collar/blue collar point man was not confident helming the boats so he hired me to. At one point, the marina we were working out of informed us they wouldn't step the masts so we had to cradle them on deck and power down the way to the next marina that would do the job. So having about an extra 15 feet of expensive carbon protruding from the bow and having to get off the side of a concrete pier taught me real fast the characteristics of a prop close to the keel and far from the rudder. That, and the draft were challenging in terms of 'alongside' docking. I quickly learned that the rudder was out of play in terms of how I was used to in terms of kick. The other thing is that the draught allowed for little to no leeway or 'drifting' your stern alongside with momentum of the turn. The docking routine became one of snaking alongside until close enough and tying up. Docking in a protected slip with a crew was zero problem and the boat is light enough that it almost acts like a dinghy once a couple of lines are in hand on dock.

As a side note, at around this time I was also acting as shore crew for the training sessions for and Open 60 Vendee competitor. Docking the boat under power(with three people total) was a similar strategy, accounting for zero leeway(16ft draft). In the case of big offshore wind, we'd deposit one crew on the dock, snake the boat alongside, and use the coach boat as a tug to push in the high windage bows. In terms of rudder wash, there is none on these boats as they are twin with a centre prop.

4. Now if you look at the underside of your 109 vs the underside of a Farr 40 your gonna see a huge difference in prop placement as well as draft. The Farr's prop is right behind the keel, which draws around 8 feet or so, whereas your prop is about midway...close enough to the rudder to affect some wash. You also don't have the same draft so probably have a tad more leeway for 'alongside' docking situations...but I'm not gonna tell you how your own boat handles!!

Anyway, that's all I've got for now. If these tip of the iceberg examples need more explanation I'd suggest a certain Dashew video that I saw many moons ago...maybe its on the internet. He does a fantastic job of explaining some close quarters handling techniques and incorporates a 'big rudder closer prop' philosophy in some of his designs. 

So, I hesitate to say sorry for the thread drift everyone, as I think this is on topic. Ultimately its Bull's call as to where he puts the prop...but to my untrained eye the prop should be a bit further back but, again its a small boat that probably enjoys benign docking opportunities in a protected slip so no harm no foul.
 

 

[Bull City]

Looks nice! Kinda hard to tell on my small screen but it looks like he has a folding prop. Maybe even takes commercially available props? That would add value for me.

Yes, it is a folding prop. Torqeedo and Aquamot (in the photo) offer them as an option. ePropulsion does not.  :angry:

 

[jdege]

I've been thinking about putting Pod Drives on my Meadowlark.

Some chasing around the web found me this:

Electric Saildrive and Pod Boat Motors

 

[Bull City]

Ultimately its Bull's call as to where he puts the prop...but to my untrained eye the prop should be a bit further back but, again its a small boat that probably enjoys benign docking opportunities in a protected slip so no harm no foul.

My docking situation is very benign 99% of the time. Even then, I am capable of fucking it up. 

I have always glided in bow first in neutral, with a minimum of backing. Since there will be no OB to be concerned about, I may try backing in. Can an old dog learn new tricks?

 

[fufkin]

Why? Because the fwd mount gives better weight location, easier and less destructive installation, and easier maintenance ... and the possible gain in manoeuvrability will be small and un-needed.  This is a low freeboard light wee boat sailing in a light air lake, where its sailing abilities are paramount.  It is not a 10-ton high windage hull which needs to maximise its chances of berthing in high winds after a hard passage.

Bull's outboard was on the transom, about 5 or 6 feet behind the helmsman's position. I doubt there was much scope for turning the outboard while manoeuvring, because abandoning the helm to jump up on the lazarette and manipulate the outboard would create a pile of new problems .

The location of the prop, or best location should over ride any so-called destructive installation. As DDW pointed out, you could install through the bulkhead once and keep a small hatch or inspection port. Nothing precludes you from placing the battery in the more desirable centred position. A proper wiring setup could go through the bulkhead without too much so-called 'destruction'. That said, I'm perfectly willing to have someone tell me that the current prop location is sufficient or even preferred in this case...its not really a deal breaker.

My comment that outboards can steer and fixed props cannot was general and not specific to Bull's boat. I started out as a kid on a 24 ft auxiliary outboard keelboat(C&C24), where I could reach the engine from behind the tiller. A little steerage in reverse from the engine when docking was a trick my Dad taught me before he turned me loose to take my Mom sailing so he could go back to the office to pay for it.

 

[TwoLegged]

The location of the prop, or best location should over ride any so-called destructive installation.

So I guess you're not going to be buying Bull's boat.  Which probably means everyone is happy, since Bull seems to have abandoned the idea of selling.

You are quite entitled to your choice on your boat, but it's a pity to hear you sounding so dogmatic about other people choosing their own priorities on their boats. 

 

[fufkin]

So I guess you're not going to be buying Bull's boat.  Which probably means everyone is happy, since Bull seems to have abandoned the idea of selling.

You are quite entitled to your choice on your boat, but it's a pity to hear you sounding so dogmatic about other people choosing their own priorities on their boats. 

I guess you missed the part where I said it's Bull's call. That means I respect his decision either way, not yours. 

As for getting lulled into a debate about what is not your call, I think yammering over drive Leg location w someone named TwoLegged and talking close quarters handling with someone named Crash(no offence Crash happy to answer you question) has me near my upper limit of internet sailing for the day.

You certainly enjoy creating a storm where there doesn't need to be one. I'm pretty sure Bull get's that this is a discussion where all ideas are welcome and will consider them as appropriate. 

You should also re-read where I said I'm happy to be told that the current prop location is the best one. By someone more qualified than myself of course. How is that dogmatic?

 

[Bull City]

Guys, I am grateful for all your comments and challenges to my ideas and each other’s. Please be nice. 
thanks. 
B.C. 

 

[Crash]

I guess you missed the part where I said it's Bull's call. That means I respect his decision either way, not yours. 

As for getting lulled into a debate about what is not your call, I think yammering over drive Leg location w someone named TwoLegged and talking close quarters handling with someone named Crash(no offence Crash happy to answer you question) has me near my upper limit of internet sailing for the day.

You certainly enjoy creating a storm where there doesn't need to be one. I'm pretty sure Bull get's that this is a discussion where all ideas are welcome and will consider them as appropriate. 

You should also re-read where I said I'm happy to be told that the current prop location is the best one. By someone more qualified than myself of course. How is that dogmatic?

None taken fufkin!    I was just curious about the difference in experiences, and can see now, why you'd go the way you'd go.  I learned to sail on Navy Luders yawls, so am well experienced with the full keel, prop in an aperture right near the rudder thing, esp as with all the overhang, et al, the prop was quite a ways forward (as was the rudder)...and on the total other side of the equation, 3 years driving an aircraft carrier with 4 props and 2 rudders...

Like many things with a sailboat, it's all a series of compromises.  As fufkin rightly points out, at the end of the day, its up to Bull to decide which series of compromises work best for him.  Our "job" is to offer our experiences and advice, which he can take or leave as he deems fit.   I think that's what 99.9% of the commentary here has been in the spirit of...

 

[Zonker]

You simply cannot compare the normal HP equals x in kWh.   There is simply a huge loss of efficiency in gas outboards.

That's a fallacy promoted by makers of electric propulsion. 1 HP = 746 Watts = 0.746 kW. That is the definition of what a HP is!

The output of outboard motors is measured at the prop shaft so there is no loss of efficiency. What you fail to realise is there IS a big difference in propeller efficiency.

Electric outboards turn bigger props slowly. They are more efficient at slow speeds than a small gas outboard prop turning quickly.

If a 2.5 HP gas outboard with an engine RPM of 5000 rpm had a 5:1 reduction ratio turned a bigger prop at 1000 RPM it would have way more low speed thrust. But it wouldn't power a dinghy well (95% of its market) and the hub would be very big to handle the expensive 5:1 bevel gears required. So you get a tiny prop spinning fast with a 2:1 cheap gear set.

The closest gas outboard that does this is the Yamaha 9.9 high thrust with a 2.92 reduction ratio and a 12" diameter prop. Compare to a Honda 9.9 with a 2.1 ratio that turns a 10-10.5" dia. prop. Both are 9.9 HP. Guess which one is better suited for powering a displacement sailboat?

 

[Bull City]

So you get a tiny prop spinning fast with a 2:1 cheap gear set.

It sounds like the eProp pod, compared to the comparable Torqeedo pod, does just this. Higher rpms, smaller prop, and no reduction gear, so I hear from @Beanie 101. Would you agree? 

 

[DDW]

In almost all situations, the larger, slower turning prop absorbing the same power will be more efficient. One complaint about the Torqeedo is the gear whine. My eProp outboard is direct drive and makes less noise than a Torqeedo. Only matters if you are bothered by it. The Torqeedo runs at 1300 prop speed vs 2300 for the eProp. The folding prop supplied for the Torqeedo is sourced from Flexofold, these have always tested well on conventional auxiliaries. For only $400 more you can get the 4 kw version which might tempt, as it may be more efficient run at 1/2 power than the 2 kw. 

 

[weightless]

No worries, just rig up an infinitely long, single bladed prop running deeply submerged at an infinitesimal velocity and attach it to a motor with gearing that matches that perfect prop to the motor's peak power. Application specific solutions are trivial and left as an exercise for the student  

In theory, I think it would be nice to have a selection of props and / or have props that a prop shop could re-pitch. That would allow for the usual prop matching. On the other hand, the perfect can be the enemy of the good. If a tiny, furiously spinning, plastic prop does an adequate job of propulsion it may come with benefits that maximize satisficing.

Yes, I will be submitting this effort to the "least helpful post of the year" contest. I think it will be very competitive.

 

[Bull City]

In almost all situations, the larger, slower turning prop absorbing the same power will be more efficient. One complaint about the Torqeedo is the gear whine. My eProp outboard is direct drive and makes less noise than a Torqeedo. Only matters if you are bothered by it. The Torqeedo runs at 1300 prop speed vs 2300 for the eProp. The folding prop supplied for the Torqeedo is sourced from Flexofold, these have always tested well on conventional auxiliaries. For only $400 more you can get the 4 kw version which might tempt, as it may be more efficient run at 1/2 power than the 2 kw. 

DDW, the Torqeedo pod drive is tempting, since I have one of their remote throttles, which I could use with their pod. But the price of their 5 HP pod with charger and battery is $2,000 more than the ePropulsion 6 HP system. The folding prop would add $900 to that. I suggested to ePropulsion that they offer a folding prop option.

I gather you're pretty happy with your ePropulsion OB. What size do you have? Do you have the NAVY Battery?

The US Aquamot dealer has not responded to my inquiry.

I heard from them US Aquamot dealer. They were not impressed with Aquamot's support. Although they are still a dealer, they use Torqeedo products because their dealer support is better.

 

[Ajorn]

Hi,

don't know whether they still do it

https://www.yachtingmedia.com/magazine/torqeedo-jefa-hanse-e-motion-rudder-drive.html

but is another kind of solution for your problem.

Happy new year

 

[DDW]

Yeah, the eProp is cheaper. The "6 HP" kinda splits the difference at 3 kw between the two Torqeedo options. I have a Spirit outboards with the integrated battery. I've been happy with it so far. The only interaction I've had with their customer service is I needed spare clamp screws (as the transom on my dinghy is quite thick) and also wanted a spare plug for the battery connection. They supplied the spare screws by cutting them off a donor unit (due to the way they are installed, can't be removed easily) and the spare plug by cutting it off also. Both without charge. I'd might have expected them to have spare screws other than the fact that they are not really exchangeable, I didn't really expect the spare plug as it is part of the wiring harness. Nevertheless they got me both. That seemed exemplary. The only problem I can see with it is the paint is bubbling slightly in a couple of places. This is the nature of aluminum, it does not hold paint well. But that's in salt water, better chance in fresh.