Jump to content

Recommended Posts

36 minutes ago, TwoLegged said:

Bull, if I am reading the drawings correctly, then the battery would fit in the mystery compartment marked by the arrow.

So why not put a hatch in the cockpit sole,and install the battery there?  That way you keep your storage drawer in the next compartment

 

Also an ideal place for a storage of wine, spirits, and other intoxicants. Put at least 12 screws in it and the totally inebriated/stoned will never figure it out, unless they meet and get a synapse together.

  • Like 1
Link to post
Share on other sites
  • Replies 825
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

Sea trial today went well. We launched TONIC without the rig, and most everything normally aboard had been stripped before the work began. No leaking! We weren't really concerned but it was encouragin

Progress and Pics Pod drive in place: Inside showing mounting bolts and cable: Battery tray & straps in place: Main On-Off switch on port settee riser, just i

Drum roll.............. Ta-Da!  

Posted Images

5 hours ago, Bull City said:

This is the area behind the bulkhead - forward of lazarette, and between P&S cockpit lockers. It's not accessible from anywhere. I would have to put a hatch in the cockpit sole to reach it. God knows what's in it.

1334395396_H-BoatAft.png.6c8566fb37da556a52d7637786f5408b.png

That adds a bit of unforeseen complexity to the mod. My main reason for suggesting moving the prop back is that, where you  propose placing it, you're losing a gear for close quarter handling and manoeuvring with prop/rudder burst to kick the stern around and pull a 360 on the spot and or when docking. It's not the end of the world but worth considering. I guess you also have to consider the size of the rudder when deciding whether this approach is worth looking at.  The other thing is, the boat will squat a bit under power and that's where I'd try to pinpoint the ideal prop position(in an ideal world independent of bulkhead restrictions), and work from there. Even where you propose it will work fine...just pointing out some possibilities.

Measure twice cut once.

 

Link to post
Share on other sites
5 minutes ago, Zonker said:

It's not going to squat with such low power.

Zonker I'll defer to you on that...I'm just checking this thread late. How close to hull speed can proposed E power get to?

Link to post
Share on other sites

The 3 kW is the larger model. That's 4 HP.  Pretty close to hull speed because the boat is a slippery 3200 lb H boat. But squatting really happens when you drive the boat PAST hull speed and the bow wavelength exceeds waterline length

Link to post
Share on other sites

If the boat could be powered to hull speed, and depending on prop placement, would there be a little bit of squat? Or am I misinterpreting it?

Isn't it basically a combo of power and placement on the hull?

_edit-I guess shape of underbody is also a variable

 

Link to post
Share on other sites
36 minutes ago, Zonker said:

The 3 kW is the larger model. That's 4 HP.  Pretty close to hull speed because the boat is a slippery 3200 lb H boat. But squatting really happens when you drive the boat PAST hull speed and the bow wavelength exceeds waterline length

How do you calculate that?

I've not found a good source for even simple rules of thumb as to how much power is required to push a displacement boat to a certain speed.

Link to post
Share on other sites

More experience than anything else for this example. I owned a San Juan 24 which had an 8 HP outboard. Roughly similar waterline and displacement. Could never use more than 2/3 the power of the engine or about 5 HP because it would squat and flood the cockpit. So 4 HP on a similar hull (roughly) gets you close to hull speed.

it does depends a lot on hull shape & displacement/L ratio. Not so much on location of prop unless you are using a very steep shaft angle.

If your sailboat is similar to the Delft Systematic Yacht Series (or even if it isn't) you can use their resistance coefficients to predict full scale resistance. It's just a regression analysis of lots of hull parameters. They create a polynomial curve to fit the tested resistance data on a huge series of scale models in a towing tank.

Note this is for Bare Hull resistance i.e. no rudder and keel. But you can use NACA L/D curves to give you Cd values for typical foils so that part is easy.

Lots of papers on it, but you could start with this one.

http://www.remmlinger.com/Regression DSYHS.pdf

Then once you have resistance you can estimate required thrust at a given speed. Estimating thrust of a particular prop at a particular RPM is beyond the scope of this course :)

 

  • Like 1
Link to post
Share on other sites
1 hour ago, fufkin said:

My main reason for suggesting moving the prop back is that, where you  propose placing it, you're losing a gear for close quarter handling and manoeuvring with prop/rudder burst to kick the stern around and pull a 360 on the spot and or when docking

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

Link to post
Share on other sites

RE: comparing the electric vs. gas motors and the "comparable" HP claim.   You simply cannot compare the normal HP equals x in kWh.   There is simply a huge loss of efficiency in gas outboards.

In the real world I've run the T1003 and the Cruise 2.0 as well as a 3.5HP and 6HP (4-strokes).   Boat is a 30', 4500+ slippery sportboat.    

The T1003 could barely make 4.5k  

The 3.5HP gas (I use this motor the most) can make 5.6-5.8k

Cruise 2.0 could make 6k

6HP gas does 6.5+

Link to post
Share on other sites
5 hours ago, solosailor said:

RE: comparing the electric vs. gas motors and the "comparable" HP claim.   You simply cannot compare the normal HP equals x in kWh.   There is simply a huge loss of efficiency in gas outboards.

In the real world I've run the T1003 and the Cruise 2.0 as well as a 3.5HP and 6HP (4-strokes).   Boat is a 30', 4500+ slippery sportboat.    

The T1003 could barely make 4.5k  

The 3.5HP gas (I use this motor the most) can make 5.6-5.8k

Cruise 2.0 could make 6k

6HP gas does 6.5+

My experience (27' 3200 lbs.) is/was T1003 will reach 4.5 knots in glassy water, a Honda 2 HP about 5.

Link to post
Share on other sites
10 hours ago, TwoLegged said:

Bull, if I am reading the drawings correctly, then the battery would fit in the mystery compartment marked by the arrow.

So why not put a hatch in the cockpit sole,and install the battery there?  That way you keep your storage drawer in the next compartment

I thought about that. I decided against it because:

  • The battery is 106 lbs. The storage bin space seems better in that it's lower and further from the ends.
  • I want to have easy access to the indicators and controls on the battery.
  • I hate cutting holes in my boat.
  • While the storage bin is handy, I really don't use it much.

I corresponded with a fellow H-Boat owner in Switzerland, who had a little diesel inboard, because he hates OBs. Fossil fuel engines were banned from his lake, so he removed the diesel and installed an Aquamot electric pod. He loves it. (The US Aquamot dealer has not responded to my inquiry.) I mention it because he had to make a hatch in the cockpit sole to accommodate the diesel.

That reminds me... I need to ask him about fouling.

  • Like 1
Link to post
Share on other sites
9 hours ago, Zonker said:

Some of the Gunboat catamarans had their saildrives mounted at a significant angle to the hull so the drive didn't protrude below the base of the hulls

Mounting it off center is no worse than a sailboat with an outboard on a bracket that is a bit offset to center to clear the rudder. A few inches either way won't matter (but ask which side because one side is better due to different direction of prop rotation). I don't know which way the prop goes. Which way is best - same or opposite?

Yes to a backing plate. The thrust is > hundred or so pounds at least. And it's continuous, and it reverses when the prop is in reverse. I agree.

And likely yes to getting rid of ancient gate valves. Gate valves don't seal well if a tiny bit of growth or debris gets in the gate and often were not bronze. Though given the age of the boat and they are still intact, they might be.

 

Link to post
Share on other sites
1 hour ago, Bull City said:

I thought about that. I decided against it because:

  • The battery is 106 lbs. The storage bin space seems better in that it's lower and further from the ends.
  • I want to have easy access to the indicators and controls on the battery.
  • I hate cutting holes in my boat.
  • While the storage bin is handy, I really don't use it much.

Fair enough.  My thinking was that a) the after compartment was still a long way from the stern, and b) there is probably some remote panel available for the battery.

But if you can live without the storage space, then the fwd location is simpler and cheaper and a better place for the weight.

BTW, I am really enjoying this thread.    I think it's kinda wonderful that this sort of auxiliary propulsion is now available more-or-less off-the-shelf, for probably less money than a new diesel.  For those of who go sailing for the sheer pleasure of the sailing and want an engine only for docking rather than passage-making, electric propulsion feels like an answer to a prayer. Have you established whether the E-Propoulsion pod does regen? 

Link to post
Share on other sites
1 hour ago, TwoLegged said:

Have you established whether the E-Propoulsion pod does regen? 

I haven't. I asked the dealer a bunch of questions just before Christmas, but haven't heard back

1 hour ago, TwoLegged said:

I think it's kinda wonderful that this sort of auxiliary propulsion is now available more-or-less off-the-shelf, for probably less money than a new diesel.  For those of who go sailing for the sheer pleasure of the sailing and want an engine only for docking rather than passage-making, electric propulsion feels like an answer to a prayer.

I agree. The Torqeedo has been great, despite its limitations. I think the pod addresses a lot of them. Plus I'll have about 1200 more Watt hours.

  • Like 1
Link to post
Share on other sites

A little hard to get the scale from the drawings, is it possible to cut a hole in the bulkhead and install the pod drive in the mystery compartment? You only need to reach in there once, to do the install. 

If it was my boat, I'd remove those cockpit drain hoses, gate valves, and thru hulls and hard plumb it with G10 tubes. No valves. No rubber hose. No hose clamps. Unless there was some compelling reason to close them routinely. 

  • Like 1
Link to post
Share on other sites
9 hours ago, solosailor said:

RE: comparing the electric vs. gas motors and the "comparable" HP claim.   You simply cannot compare the normal HP equals x in kWh.   There is simply a huge loss of efficiency in gas outboards.

In the real world I've run the T1003 and the Cruise 2.0 as well as a 3.5HP and 6HP (4-strokes).   Boat is a 30', 4500+ slippery sportboat.    

The T1003 could barely make 4.5k  

The 3.5HP gas (I use this motor the most) can make 5.6-5.8k

Cruise 2.0 could make 6k

6HP gas does 6.5+

The frequent claim of "a huge loss of efficiency in gas outboards" makes as much engineering sense as the electric industries "equivalent horsepower". Alternative facts may play well in politics but are useless in engineering. Your results pretty much confirm that horsepower is horsepower, however produced.

T1003 (1000 watts or 1.3 hp) made 4.5 knots

3.5 hp gas made 5.7 knots

Cruise 2.0 (2000 watts or 2.6 hp) made 6 knots

6 hp gas made 6.5 knots.

That's pretty much the expected curve for a displacement hull. The slight deviation of the 3.5 gas can easily be explained by having the prop and gearing poorly matched to the speed. Horsepower is a physical quantity and is supposed to be measured at the output shaft. Doesn't matter if it is electrons or gas explosions or rubber bands or squirrels spinning it.  Prop efficiency is another matter, it may be more convenient to make an electric with a slower, more efficient prop, but there are gas outboard that do that too. 

  • Like 2
Link to post
Share on other sites
10 hours ago, TwoLegged said:

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.

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.

Link to post
Share on other sites
9 hours ago, solosailor said:

RE: comparing the electric vs. gas motors and the "comparable" HP claim.   You simply cannot compare the normal HP equals x in kWh.   There is simply a huge loss of efficiency in gas outboards.

I don't want to jack the thread but AFIK <-- not much on this -- most of the potential comparative efficiency losses of gas outboards are accounted for in the rating. In the US, at least, I believe gas outboards are rated at the prop shaft.

International Council of Marine Industry Associations Standard No. 28-83 3.3.1--Power shall be declared as Propeller Shaft Power at the propeller shaft of engines sold with complete propulsion units

IME, a Honda 2.3 (1.7kW at the prop shaft) is noticeably more powerful on a small keel yacht than a 1003 (1kW at the battery). I haven't taken data and haven't made any effort to optimize the props -- using stock on both. So, there are confounding issues. Still, the difference is obvious and doesn't support the theory that electric outperforms its rating. My feeling is that shp is a reasonable way to get a quick comparison of the propulsive work a gas or electric or steam or whatever auxiliary can do. YMMV, and I'm happy to let it go at that.

Link to post
Share on other sites
35 minutes ago, fufkin said:

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

Link to post
Share on other sites
1 hour ago, fufkin said:

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.

image.png.1e1dd290837d12eda593984f1b18604f.png

  • Like 1
Link to post
Share on other sites
1 hour ago, fufkin said:
12 hours ago, TwoLegged said:

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.

 

1 hour ago, fufkin said:

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 .

  • Like 3
Link to post
Share on other sites
2 hours ago, Crash said:

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.
 

 

Link to post
Share on other sites
27 minutes ago, weightless said:

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:

Link to post
Share on other sites
21 minutes ago, fufkin said:

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?

  • Like 1
Link to post
Share on other sites
3 hours ago, TwoLegged said:

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.

Link to post
Share on other sites
57 minutes ago, fufkin said:

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. 

Link to post
Share on other sites
1 minute ago, TwoLegged said:

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?

Link to post
Share on other sites
54 minutes ago, fufkin said:

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...

 

  • Like 1
Link to post
Share on other sites
17 hours ago, solosailor said:

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?

  • Like 7
Link to post
Share on other sites
14 hours ago, Zonker said:

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? 

Link to post
Share on other sites

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. 

Link to post
Share on other sites

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.

 

  • Like 3
Link to post
Share on other sites
1 hour ago, DDW said:

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?

On 12/28/2020 at 8:49 AM, Bull City said:

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.

Link to post
Share on other sites

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. 

  • Like 1
Link to post
Share on other sites
On 12/13/2020 at 5:41 PM, DDW said:

I'd worry a little about longevity, there are signs of corrosion on my Spirit after only one year use (but to be fair, the same can be said of most outboards).

I sent my Spirit 1.0 back to Nestaway for a replacement part after a year as I ran over a rope - they called me to say that they weren't happy with the paint and some corrosion on the bulb and would be replacing the motor which they promptly did. I've had the replacement for 18 months with no sign of corrosion at all. I think he mentioned to me on the phone that there were some early batches that had the problem so it may be worth enquiring?

I too would not go back to a petrol outboard. My main reason apart from the quiet and lack of smell is that my wife and daughter have no problems jumping in the boat and pressing go - they didn't feel that way about the petrol.

  • Like 1
Link to post
Share on other sites
2 minutes ago, TwoLegged said:

@chester, from what I read, the compensation block remains outside the hull, and has to be trimmed to fit the hull contours.

right, so then a mounting plate tha spans the chanel and ecceps the bolts on a flat plane should be pretty easy, no?  assumes enough length in the bolts to go through, laminate and the plate.

Link to post
Share on other sites
2 minutes ago, chester said:

right, so then a mounting plate tha spans the chanel and ecceps the bolts on a flat plane should be pretty easy, no?  assumes enough length in the bolts to go through, laminate and the plate.

Yes, but as Bull pointed out, the plastic riser for the cables sits right in the middle of the drainage channel, so there will be some blockage of the flow to the bilge sump.

Link to post
Share on other sites
19 minutes ago, TwoLegged said:

@chester, from what I read, the compensation block remains outside the hull, and has to be trimmed to fit the hull contours.

 

14 minutes ago, chester said:

right, so then a mounting plate tha spans the chanel and ecceps the bolts on a flat plane should be pretty easy, no?  assumes enough length in the bolts to go through, laminate and the plate.

 

10 minutes ago, TwoLegged said:

Yes, but as Bull pointed out, the plastic riser for the cables sits right in the middle of the drainage channel, so there will be some blockage of the flow to the bilge sump.

You fellows have it right. I think it was  @Ishmael who suggested off setting the pod so as to avoid the drainage channel. I kinda like that idea.

One thing I'm wondering about is a backing plate. I think it will also need to be a "compensation block" from the other side. Maybe a glob of MarineTex flat on top?

Link to post
Share on other sites

What I'd envision, in the inside of the hull, is something like a mirror of the compensation block.

A block shaped to match the hill, perhaps, in plywood, then glassed in, and covered with a backing plate.

But is there a reason you couldn't shape the block with limber holes running through it?

Link to post
Share on other sites

So I'm just spitballing here, but...an inboard diesel with saildrive has the motor mounted to two long blocks of wood that are themselves adhered to the hull, and then glassed (tabbed) to the hull to spread the thrust loads from the engine/saildrive combination to the hull.  

That compensation wedge doesn't look to have enough surface area to spread the thrust loads over a large enough area to me...I'd want maybe a piece of 3/4 in ply that was maybe 6in x 18in  or maybe 2 1/2in thick ply pieces, the first one 6 x 18, and the second maybe 4 x 12 (inches)  aligned fore and aft to help distribute thrust loads. 

 I'd also put an epoxy fillet under the ply to make a level mounting surface if mounting on centerline.  If off set, I'd still set the ply in an epoxy fillet bed, and then maybe make a smaller fillet on top to make a level surface for the nuts/washers...

Zonks, or one of the other actual Naval Engineering types can tell me I'm overthinking it...which is of course, entirely possible, and maybe even likely. :P  

Link to post
Share on other sites

I'd never encapsulate plywood in a boat, ever. All you need inside is a flat spot for the nuts. That could be done with just thickened epoxy, personally I'd use some blocks of G10 shaped somewhat to fit the valley - don't need to be a perfect fit at all - then bed them in thickened epoxy. Then I'd poor some filler behind it, troweled to level with the flat spot and sloping downhill from the limber hole in the aft bulkhead. Epoxy filled with a light weight filler would be fine, or foamed epoxy. Now any water will flow over and not get trapped, you won't always be looking at it when it's hauled and explaining to everyone that no, you didn't f**k up, you really meant it to be ass-sideways, and the extra work will take you about an hour.

Also keep in mind, you really just need two flat spots of the bolts, and they don't have to be the same flat spot at the same level. The wiring conduit you want standing above it all (and any water in there) anyway. 

  • Like 2
Link to post
Share on other sites

A lot to take in. Thanks very much. I’ll keep y’all posted. I’m still waiting for some answers to product questions from the eProp dealer. Seem like nice people. 

Link to post
Share on other sites

Let's not forget the thrust of this motor is around 100 lbs. Like a small 4 HP outboard. Think of how much material is in a dinghy transom...This is how I'd approach it.

Timage.thumb.png.1fe5c133247846e23153d998551375d5.png

The extra layers of glass are optional and depend on how thick your hull is. But the bolts should be mostly in tension (from the thrust moment) and secondarily in shear. You just have to keep them from pulling through the hull when you hit a big log.

 

 

  • Like 1
Link to post
Share on other sites

The other thing I'm working on is how to fit everything into the space under the cock pit, and just aft of the companionway.

image.png.fa51eba61e588b3bcb5da85ee8e6088d.png

I'm thinking of mounting the pod to the aft end, kind of between the through hulls, possibly off set a little bit. Then I would fabricate a flat platform for the battery, control unit, and charger, that would occupy the space forward of the through hulls. My inner anal retentive self says that the 100+ lb. battery should be on the centerline, but there would be some benefit in placing it to one side. The real estate gets pretty tight. Thoughts?

The horizontal space forward of the through hulls is about 26" side to side X 23.5" fore & aft. The footprint of the components are:

  • Battery 21.85" X 17.32" (15.35" without removable handles; plugs, indicators & controls on 21.85 front). I don't think it has mounting holes; waiting to get that answered. In the absence of mounting holes, I would have to include some structure to contain the battery while the boat heels.

The other components have mounting holes:

  • Control Unit 9.25" X 5.10" (cables on either side of long side)
  • Charger 235*175 9.25" X 6.88" (wires from both narrow sides)

I need to arrange it so the connected cables aren't overly tortured.

Link to post
Share on other sites
20 minutes ago, Zonker said:

Let's not forget the thrust of this motor is around 100 lbs. Like a small 4 HP outboard. Think of how much material is in a dinghy transom...This is how I'd approach it.

Timage.thumb.png.1fe5c133247846e23153d998551375d5.png

The extra layers of glass are optional and depend on how thick your hull is. But the bolts should be mostly in tension (from the thrust moment) and secondarily in shear. You just have to keep them from pulling through the hull when you hit a big log.

@Zonker , this very helpful. Thank you. When you look at the drawing of the boat, like at post 102, can you determine the thickness of the hull? I've got some other drawings, but I don't know enough to tell.

The pod would be 1.5 to 2 feet behind the keel, so hitting a log would be unlikely.

Link to post
Share on other sites

Logs sometimes hit a keel, bounce along sideways and then bang the hull a bit. Here in the great Pacific SouthWest, we have lots of experience with logs.

I'm sure the thickness shown on the drawing is just a nominal to show thickness. When you drill the first bolt hole, look at the thickness of the hull then. If less than say 4mm (3/16") add some reinforcement patches. Don't have to be huge - 3" or so across. It's just to stiffen up the hull locally so it doesn't flex.

  • Like 1
Link to post
Share on other sites

His photos indicate quite a bit of wine glass to the shape right at the CL. That's why I'm thinking on CL. Otherwise you are mounting on quite a slope, unless you go really off center. On the other hand you don't have to fill very much of that wine glass to make the flat spot. Further, the section drawing way back shows pretty good slope coming forward, so you don't have to mount it very far forward of the bulkhead to still get a downhill run from the limber hole to the flat spot which would be filled for drainage. Again on the outside, you'll have to shape that block with a serious slope if only a little off center. If on center, it'll have a ditch through it, to match but symmetrical and won't try to climb up the side when you tighten the bolts. Also, the wineglass at the CL makes it already pretty stiff there. Less so the further off CL you go. 

Link to post
Share on other sites

Turns out the class has scanned some of the drawings and layup: https://h-boat.org/en/documents-rules/drawings

I suspect discovering as built right where you need to know will happen just after the drill is removed. The guy poking laminate into the mold may or may not have had his Wheeties that morning but I'm sure they got in the general neighborhood of spec.

image.png.0a6a53bbc52109d170177a5e96833d4e.png

  • Like 1
Link to post
Share on other sites
1 hour ago, Bull City said:

I'm thinking of mounting the pod to the aft end, kind of between the through hulls, possibly off set a little bit. Then I would fabricate a flat platform for the battery, control unit, and charger, that would occupy the space forward of the through hulls. My inner anal retentive self says that the 100+ lb. battery should be on the centerline, but there would be some benefit in placing it to one side. The real estate gets pretty tight. Thoughts?

The horizontal space forward of the through hulls is about 26" side to side X 23.5" fore & aft. The footprint of the components are:

  • Battery 21.85" X 17.32" (15.35" without removable handles; plugs, indicators & controls on 21.85 front). I don't think it has mounting holes; waiting to get that answered. In the absence of mounting holes, I would have to include some structure to contain the battery while the boat heels.

The other components have mounting holes:

  • Control Unit 9.25" X 5.10" (cables on either side of long side)
  • Charger 235*175 9.25" X 6.88" (wires from both narrow sides)

I need to arrange it so the connected cables aren't overly tortured.

Bull, I still like my idea of mounting the battery on a cradle which is mounted to slides on the bunk fronts.  That way if you want access to the pod mountings or the cockpit drains, the the battery can be easily slid out and removed.  It would also allow a different battery to be fitted in future, simply by modifying the cradle..

I don't think that the design and construction of the cradle would require any great skill.

Link to post
Share on other sites
10 hours ago, TwoLegged said:

Bull, I still like my idea of mounting the battery on a cradle which is mounted to slides on the bunk fronts.  That way if you want access to the pod mountings or the cockpit drains, the the battery can be easily slid out and removed.  It would also allow a different battery to be fitted in future, simply by modifying the cradle..

I don't think that the design and construction of the cradle would require any great skill.

I like your idea too. That’s what I’m planning to do. 

  • Like 1
Link to post
Share on other sites
11 hours ago, DDW said:

His photos indicate quite a bit of wine glass to the shape right at the CL. That's why I'm thinking on CL. Otherwise you are mounting on quite a slope, unless you go really off center. On the other hand you don't have to fill very much of that wine glass to make the flat spot. Further, the section drawing way back shows pretty good slope coming forward, so you don't have to mount it very far forward of the bulkhead to still get a downhill run from the limber hole to the flat spot which would be filled for drainage. Again on the outside, you'll have to shape that block with a serious slope if only a little off center. If on center, it'll have a ditch through it, to match but symmetrical and won't try to climb up the side when you tighten the bolts. Also, the wineglass at the CL makes it already pretty stiff there. Less so the further off CL you go. 

Good points. The CL looks like the way to go. 

Link to post
Share on other sites
17 hours ago, TwoLegged said:

I don't think that the design and construction of the cradle would require any great skill.

Not quite the same as I plan to DIY the battery from cells, but the principle works nicely and took me an afternoon to fit. (Now glueing it in addition to the screws that already hold everything solidly enough as is. Then painting and hoping using non marine ply will be sufficient. Or replace it a few years earlier in the worst case.)

Still needs to be bolted to avoid accidentally sliding around, but otherwise a really nice solution. 

1E8333C3-CD48-477F-A011-0BD0A4A7EB48.jpeg

50734224-984B-4D3B-9252-37C862CC2914.jpeg

Link to post
Share on other sites
On 12/29/2020 at 7:48 PM, Ajorn said:

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

For other boats a similarsystem as Hanse had been applied. For the 315 Hanse asks for the electic propulsion option EUR 10,000 resp. EUR 15,000 with fast charging (3 hrs). Motor is 4 kW with 6.11 kn Top Speed and a range of 30 nm at 4.5 kn. Weight saving versa diesel is 100 kg. Have a look at the turning circle in the video!

https://www.pinterest.de/pin/782993085191149125/

https://www.mfboat.com/about/when-the-wind-dies/?lang=en

IMG_5462.jpg

 

  • Like 1
Link to post
Share on other sites
19 hours ago, allweather said:

Not quite the same as I plan to DIY the battery from cells, but the principle works nicely and took me an afternoon to fit. (Now glueing it in addition to the screws that already hold everything solidly enough as is. Then painting and hoping using non marine ply will be sufficient. Or replace it a few years earlier in the worst case.)

Still needs to be bolted to avoid accidentally sliding around, but otherwise a really nice solution. 

1E8333C3-CD48-477F-A011-0BD0A4A7EB48.jpeg

50734224-984B-4D3B-9252-37C862CC2914.jpeg

Allweather,

It looks good. A few questions:

  • What is the weight of your batteries?
  • How are you bolting into place? Into the bunk/berth risers?
  • What are doing with the storage bin?
Link to post
Share on other sites

Bolting into the risers would be the easy way. But since I don't want to drill holes I'll glue some teak(delrin would be even nicer) blocks where there is now space between the hull and the box in the second picture. Just one for each corner. Then going to screw into them when the box is in place. For sliding it out I'll just have to remove those four screws.

Batteries are still on order but will be around 44kg. The box is made from 8mm plywood and really quite strong, likely overengineered but I wanted to be sure with the mass involved.

The storage bin still has enough space to fit with my personal arrangement since the single cells are only 175mm wide. There is just enough space behind the storage bin if you pull it out under the step from the companionway. About 240mm at max. Posting a picture in a second.

C4C4AA8A-2DB7-4282-B5E9-90D45B4D9957.jpeg

36E21F79-17C3-4941-9107-76D5DA7D27E9.jpeg

Link to post
Share on other sites

I am pretty much in a "go" mode on this. Reservations are:

Questions I have asked the dealer which they have referred to ePropulsion and haven't heard back:

  • Is the pod able to handle continuous immersion for 12 to 18 months?
  • Does the prop free wheel when sailing, or does it lock? Can it be locked in a vertical position? If it free-wheels, does this result in wear or damage?

And another they are working on:

  • Can you put me in touch with someone who has had one for a while?
     
  • Like 2
Link to post
Share on other sites
31 minutes ago, Beanie 101 said:

There’s a new version of the Pod coming out in the next few months, with hydro-generation through the propeller.  There’s nothing official from eProp yet but a German distributor is showing bare bones details https://www.greenboatsolutions.de/en/shop/hersteller/4/ePropulsion.

Very interesting. Thanks for spotting it and posting it here. One bit of news that I was pleased to see is that they're going to offer a folding propeller with their pod drives. This would pretty much seal the deal for me.

They describe the new pod as having "recuperation" which I assume is regeneration via the propeller.

They quote a price of "2.599,00 € incl. VAT." How much is VAT?

 

Link to post
Share on other sites

i linked to this https://endless-sphere.com/forums/viewtopic.php?t=108411&amp;start=25 from SA in today...can't remember how :blink:  But using the bike hub tech could be a straight forward path to switching out existing outboards and sail drives? I have a 2 hp suzuki 2 banger in the garage ...take the ICE off and flange up the hub drive to the driveshaft, leg and  prop, no?

Link to post
Share on other sites
43 minutes ago, Bull City said:

Very interesting. Thanks for spotting it and posting it here. One bit of news that I was pleased to see is that they're going to offer a folding propeller with their pod drives. This would pretty much seal the deal for me.

They describe the new pod as having "recuperation" which I assume is regeneration via the propeller.

They quote a price of "2.599,00 € incl. VAT." How much is VAT?

 

Yes, the propeller provides power but only above a certain speed. On the Spirit EVO it’s four knots.

German VAT has been going up and down a bit recently but is normally 19%.

The eProp 2021 catalogue has now been published - see https://issuu.com/epropulsion/docs/epropulsion_catalog_2021.

Link to post
Share on other sites
1 hour ago, Beanie 101 said:

Yes, the propeller provides power but only above a certain speed. On the Spirit EVO it’s four knots.

German VAT has been going up and down a bit recently but is normally 19%.

The eProp 2021 catalogue has now been published - see https://issuu.com/epropulsion/docs/epropulsion_catalog_2021.

I don't see a folding prop in the catalogue. It's probably their way of driving me mad.

Link to post
Share on other sites

I see from the catalog that they're adding a dual control.

That means I no longer have to worry about jury-rigging one.

Link to post
Share on other sites
1 hour ago, Beanie 101 said:

German VAT has been going up and down a bit recently but is normally 19%.

Geez, and here I thought California was bad :blink:

Link to post
Share on other sites
1 hour ago, Crash said:
3 hours ago, Beanie 101 said:

German VAT has been going up and down a bit recently but is normally 19%.

Geez, and here I thought California was bad :blink:

That's a little below average in Europe, where most country's VAT rates are a little over 20%.  On the other hand, most Europeans don't pay a squillion dollars a month in health insurance and co-pays.

@Bull City needn't worry about VAT on his electric drive components.  VAT s not chargeable on exports

Link to post
Share on other sites
2 hours ago, Bull City said:

I don't see a folding prop in the catalogue. It's probably their way of driving me mad.

Thanks for spelling it right, but a catalogue is usually a relic of what they used to have.

Link to post
Share on other sites
44 minutes ago, TwoLegged said:

That's a little below average in Europe, where most country's VAT rates are a little over 20%.  On the other hand, most Europeans don't pay a squillion dollars a month in health insurance and co-pays. Let's hear it for socialism!

@Bull City needn't worry about VAT on his electric drive components.  VAT s not chargeable on exports

I knew that. I was trying to figure out what the price was without VAT.

Link to post
Share on other sites

The new items will take a while to arrive and in some cases a long while.  I suspect that some of them will be in high demand.  For example, the next shipment to the UK may not be until March and German distributors mention April for items in the Katalog.  A 12V power take-off adapter has been on the cards for several monthe and may not arrive until even later.  I think that the folding prop may be the same.

Link to post
Share on other sites
1 hour ago, Bull City said:

I knew that. I was trying to figure out what the price was without VAT.

VAT doesn't matter, it's collateral damage. Just take the price today, double it, and add in 38% for VAT and 23% for attitude.

Link to post
Share on other sites
57 minutes ago, Ishmael said:

VAT doesn't matter, it's collateral damage. Just take the price today, double it, and add in 38% for VAT and 23% for attitude.

Man maths, much? ;) 

Link to post
Share on other sites
10 hours ago, Beanie 101 said:

The new items will take a while to arrive and in some cases a long while.  I suspect that some of them will be in high demand.  For example, the next shipment to the UK may not be until March and German distributors mention April for items in the Katalog.  A 12V power take-off adapter has been on the cards for several monthe and may not arrive until even later.  I think that the folding prop may be the same.

I mentioned this to my dealer, and they confirmed that there are new products, but were sworn to secrecy. What does a "12V power take-off adapter" do? Allow you to run a 12V system off a 48V battery?

I was also wondering about running the eProp pod drive, which is 48V with a 24V battery. Could it be done? Are there draw backs? The reason I ask is that Torqeedo makes a 24V LI battery with 3500 Wh, which would fit nicely in my storage bin. It would provide ample range. Also, I have a Torqeedo remote throttle.

Link to post
Share on other sites