Powertrain choices

[Art]

Yo Reuben - I was not trying to be correct or incorrect... just posing question.

Howard Arneson has best of both worlds... stratght shaft out the transom that alters camber for direction adjustment. That and his unique props are why his jet engine powered craft go over 200 mph... if desired. I go past Howard's shop often. Have watched his rigs in action on SF Bay. Impressive!

 

[Capthead]

You did say a 30' boat, right? Stuffing twin diesels in a 30 is insane unless you are talking about the new Yanmar light weight throw away type engines. The older conventional diesels weigh a ton, will slow the boat due to weight and in the long run not be a good choice. I had a 30' cabin cruiser gas and I ran 18kts burning 4 gph. I don't know how you beat that. Re think the boat.
40 plus, go diesel.

 

[Art]

You did say a 30' boat, right? Stuffing twin diesels in a 30 is insane unless you are talking about the new Yanmar light weight throw away type engines. The older conventional diesels weigh a ton, will slow the boat due to weight and in the long run not be a good choice. I had a 30' cabin cruiser gas and I ran 18kts burning 4 gph. I don't know how you beat that. Re think the boat.
40 plus, go diesel.

In context I concur w/ Capthead... Gas engine (single or twin) can be fast, light, efficient, and affordable in smaller cruisers. Diesel weight and torque is for pushing some size and mass through, or over, the water with big props.

 

[Darylat8750]

Bob,
VW, Corvair, Tucker.

Don't know about the Italian things but all rear engined cars seem to be a failure except the Porsche. And being German it dosn't need to be a design success. They make all their odd designs look like they've seen the light and the rest of the world is in the dark. Air cooled VWs and BMW motorcycles w the cyl heads right where one's feet belong come to mind.

Outboards on the stern work well because the're light. Not so much anymore but compared to an IO w a car or truck engine plus a big heavy IO even the 4 stroke OBs are light.

I'm not say'in engines in the stern don't work. I am say'in engines placed near the center of the boat work BETTER. Balance is a huge part of boat design and the engine in the center of the boat can't be beat.

FF,
IH is belly up aren't they? You're suggesting rebuilding old farm machinery and marinizing it? Never heard of an IH in a boat. But before they did it never heard of a JD in a boat either. But they still make JDs. The're are no marine engines anymore so all boat engines come mostly or entirely from cars and trucks. That in itself is bad but an economic necessity. What is an IH 360? Six, 8 cyl and how long ago did they stop making them. Is it an extremely common farm engine and w parts readily availible? And if it's such a good engine why aren't boaters regularly replacing their Lehman's w the IH 360? If I had a tired or screwed up Lehman I'd want to know all about this IH. I think rebuilding a Lehman is a questionable undertaking just so one dosn't need to fabricate new engine mounts. Surely there are other good engines too.

I'm not knocking the IH engine FF. But you've mentioned it many times over the years and no real information has surfaced.

My friend put a pair of IH engines in his rebuild / modification of a fire damaged Hat 53. Great engines. Many many thousands of them built and in use in over the road trucks. He bought two out of wrecked trucks and rebuilt them in his garage with the help of a guy that builds diesel pulling trucks. Parts are readily available and reasonably priced. The boat has made several trips between isla Mujeres and fort Meyers. Through the Panama Canal twice and all over the Western Carribean. He gets 8.2 knots @ 4 gallons an hour.

 

[Nomad Willy]

Great info Dary,
What displacement and configuration ... inline 6 I suppose. Most or all NA? Direct injection or a pre-chamber. All completely mechanical? What are rpm ratings for power? Are there different models? Different configurations like 4 or 8 cyl? Counter balancers? Are they mostly truck engines?

I'll bet there are some here that have old Perkins and Lehmans and would like to upgrade.

 

[Darylat8750]

Eric,

His are inline 6 cyl. Large displacement ... I think 570 cu. in. Max rpm 1850 but he has over pitched his props so would never try full throttle even to see what it would turn. He has EGT gauges on them and uses a max of 900 as a limit. Usual cruise EGT of just under 800. They are turbo-ed but at his cruise power the turbos are not making any boost so he is considering removing them. A friend that owns a truck towing business near I80 got the engines for him out of wrecks. With the overhauls and marinization he has less than $10k per engine in them. (I don't know if that includes the transmissions but I don't think it does.)
He cruises between 800 and 850 rpm and about 800 degrees EGT. That keeps enough heat in them to keep them happy.

 

[markpierce]

Some people like complications and high-maintenance systems. Not me.

 

[FF]

From what I see the boat assembler LOVE the single hole drive , really fast for only modest skilled labor to install.

The boats perform OK, but the few owners that keep a boat over 5 years would never purchase that style drive again.

The maint expen$e is horrible , compared to simple shafts or a CPP.

Save a few % in fuel, replace 3 -4 ,,$25,000 drives every other year, you chose!

 

[dhmeissner]

All this talk about boats and motorcycles leads to this:

Motorcycle Powered Boat - YouTube

 

[Art]

Dave - Thanks for posting the video!

That's one of the the funniest, dumbest, most unusual and most dangerous "boating" experiements I've seen. Someone falls off and chopped meat could easily be the outcome. Those guys have too much time on their hands! lol

 

[rjtrane]

Diesel Power in 30' Cruisers & Trawlers

Many 30 foot (plus or minus) cruising yachts that perform in the mid ranges (semi-planing plus) have single diesels installed. The cruising/trawler market place essentially demands diesel power over gas inboard - the weekender is a different market where gas is OK.

We are working on a 30' design for a cruising yacht that would have a single diesel inboard - the biggest motor we would offer is the Yanmar 350 HP - this diesel has the best HP/weight ratio that I know of - 1,000# is what it weighs (i.e. Volvo D6s are closer to 1,500# at HPs up to 435). The Yanmar is based on a Toyota V-8 truck motor - I don't think of this modern diesel as throw-away.

For maximum speed and efficiency, it can be matched with Yanmars new dual-prop I/O.

I feel there is nostalgia on this site for the old-fashion, slow-turning, naturally-aspirated diesels (i.e. Gardner bus motors). Yes, these were wonderful motors - but in today's marketplace, more efficient, high-speed diesels are what is being manufactured and that's what a new-motor buyer has to choose from.

The goal is to match the motor(s) and drive trains currently available to the boat and her intended purpose. Not to yearn for bygone days - a fantasy I sometimes pursue thinking how wonderful it would be to design a steam-powered cruising yacht.

 

[Capthead]

I have a slip neighbor with a 50' Pacemaker repowered with Yanmars. He cruises at 18 kts. and fishes Cabo for a week then a quick run back to LA. He loves them, they get great fuel mileage and will push his boat to 24 kts. WOT.

For me and my GB42 they are very impractical. A slow turning heavy cast iron diesel fits my bill just fine. Lots of torque down low baby. My kind of engines.

 

[Nomad Willy]

Capthead,
The extra weight of those big old engines isn't doing you any good. You may "like" heavy never considering the wonderful benefits of lightness. For example heavyness is probably the main reason the GBs are known as a "wet" boat. Heavy engines AND heavy boat = HEAVY.

And engine speed isn't evil. A light high speed engine will almost certainly last many times as long as you will ever run your boat. A smaller high speed engine of the same power output (or ideally less) will almost certainly vibrate less and may be quieter too.

But in defense of your old Fords they are probably working well enough and you have them in your boat and own them. Re-powering costs money.

 

[rjtrane]

Art - I apologize for missing the "?" in your post. It was a question.

 

[psneeld]

Heavy engines are PERFECT if the designed weight and placement are well though out and the weight is insignificant if much of that weight is dual purpose as ballast (as the designer intended).

I'm pretty sure hull shape is why Grand Banks and hundreds of other boats are "wet boats"....little flare and little buoyancy at the stem allows them to plunge a bit and crosswinds throw the spray aboard.

 

[ranger58sb]

Chris.

Pod drives come in twins, triples and quads. Except for a prototype ZF with integrated bow thruster (not in the pod but interfaced). I have driven this single - the joystick handling is not as good as an IPS or Zeus. Cost is high - not a value.

If you're looking to match the performance of pod drives with a single, a dual-prop I/O has similar performance and economy of operation. If you cruise a lot, fuel savings will pay for additional maintenance.

Counter rotating props perpendicular to the waterline will always outperformed slant shafts.

Yes, I'm aware of the twin/triple/quad thing. I've seen a review of a single POD drive -- I was thinking it was IPS, but could have been Zeus (but maybe it was the ZF prototype?) -- in a center console...

In any case, I was also thinking about corrosion. I'm under the impression the pods are engineered to be submerged all the time and therefore more resistant to corrosion than I/O legs... which usually can't be completely lifted/tilted out of the water during periods of non-use.

And then they're designed to shear; not sure I/O gear will do that gracefully. (Well, I guess graceful is a relative term, in this sense )

And I'm thinking this for boats somewhere between 40-55' too... mostly at displacement and semi-displacement speeds

??

-Chris

 

[hollywood8118]

Capthead,
The extra weight of those big old engines isn't doing you any good. You may "like" heavy never considering the wonderful benefits of lightness. For example heavyness is probably the main reason the GBs are known as a "wet" boat. Heavy engines AND heavy boat = HEAVY.

And engine speed isn't evil. A light high speed engine will almost certainly last many times as long as you will ever run your boat. A smaller high speed engine of the same power output (or ideally less) will almost certainly vibrate less and may be quieter too.

But in defense of your old Fords they are probably working well enough and you have them in your boat and own them. Re-powering costs money.

Eric..
It might be the Friday night Margaritas that makes me write this post but...you are so wrong on most of this post

GB are "wet" because they have a fine flat entry that allows the wave to climb pretty much unimpeded up the hull as the bow submerges in a wave.
That fine entry is also what gives the GB a soft motion in a head sea.. and their beautiful ( except in the opinion of a former well known poster on the forum).

As far as the " heavy" old Lehman vs a new buzzy, light, fast turning 4 banger there is no way I would want to listen to the harmonics of one of those things... especially in a GB.. and a wood GB is known for its quiet ride as the hull doesn't resonate as much as the glass ones.

For a cruising boat a slower turning engine is way easier on the person standing over it
HOLLYWOOD

 

[markpierce]

For a cruising boat a slower turning engine is way easier on the person standing over it

A sixteen to eighteen-hundred RPM four-banger is easy to stand over.

 

[Nomad Willy]

Hollywood I don't think they have a fine entry at all. Look at Giggitoni's avatar as seen on Gen Discussion - New Boat Toy post #2. Big (and beautiful bow wave. Fine entry boats have a long and small bow wave. How could a wide to very wide boat have anything but a blunt entry unless it was shaped like a wedge .. and GBs aren't shaped like wedges. Heavy boat / wide entry angle = wet boat. The high angle of deadrise fwd is what gives the GB it's nice soft ride.

I'm not putting the GB boat down as I'd love to have one (32) myself. But my point is that they'd be better boats if they lost about 25% of their mass.

Mark says "A sixteen to eighteen-hundred RPM four-banger is easy to stand over."

And a 2700rpm Yanmar is even easier to stand over. Higher rpm = higher frequency vibrations that are easier for a well matched engine mount to isolate. Each power stroke has less intensity or force. The engine moves less and shakes the boat less. Lower frequency vibration is much better at shaking hull bottom sections, cabin sides and bulkheads. Take it to an extreme and visualize a 60' boat powered by a 30hp engine. You're not going to feel much if any engine vibration. The engine is just too small. Now imagine it powered by a 500hp 2 cyl engine that turns 700rpm. You could probably feel the vibration on the beach as the boat went by.

A small engine turning fast w lots of cylinders is going to be smooth.

 

[hollywood8118]

Hollywood I don't think they have a fine entry at all. Look at Giggitoni's avatar as seen on Gen Discussion - New Boat Toy post #2. Big (and beautiful bow wave. Fine entry boats have a long and small bow wave. How could a wide to very wide boat have anything but a blunt entry unless it was shaped like a wedge .. and GBs aren't shaped like wedges. Heavy boat / wide entry angle = wet boat. The high angle of deadrise fwd is what gives the GB it's nice soft ride.

I'm not putting the GB boat down as I'd love to have one (32) myself. But my point is that they'd be better boats if they lost about 25% of their mass.

Mark says "A sixteen to eighteen-hundred RPM four-banger is easy to stand over."

And a 2700rpm Yanmar is even easier to stand over. Higher rpm = higher frequency vibrations that are easier for a well matched engine mount to isolate. Each power stroke has less intensity or force. The engine moves less and shakes the boat less. Lower frequency vibration is much better at shaking hull bottom sections, cabin sides and bulkheads. Take it to an extreme and visualize a 60' boat powered by a 30hp engine. You're not going to feel much if any engine vibration. The engine is just too small. Now imagine it powered by a 500hp 2 cyl engine that turns 700rpm. You could probably feel the vibration on the beach as the boat went by.

A small engine turning fast w lots of cylinders is going to be smooth.

I guess you missed the point... look at the flair of the GB VS, the Selene in the attached photos.. almost no flare at the bow of the GB vs substantial flair on the Selene.

The added flair:

1. adds reserve buoyancy as the bow goes into a wave
2. deflect spray away from the boat vs allow it to climb the hull

I have yet to be on a boat with a high rpm motor that I would want to stand over for any length of time. I have a friend with one of those cute Ranger tugs that you cannot wait to shut off the 2800 rpm motor as it will drive you nuts.
On a fast boat where the engine is way in the back it's great.. just not on a trawler.
Even on the Dashew boats if I real his typical speed curves he runs @ 1600/1800.
I have never seen a engine in any car, boat, airplane where a 4cyl. smaller higher rpm ( to get equal power ) is as smooth as a 6cyl. motor.

If you are trying to get a less costly initial investment for a close cruising boat the 4cyl. wins.

HOLLYWOOD

 

[psneeld]

I guess you missed the point... look at the flair of the GB VS, the Selene in the attached photos.. almost no flare at the bow of the GB vs substantial flair on the Selene.

The added flair:

1. adds reserve buoyancy as the bow goes into a wave
2. deflect spray away from the boat vs allow it to climb the hull

I have yet to be on a boat with a high rpm motor that I would want to stand over for any length of time. I have a friend with one of those cute Ranger tugs that you cannot wait to shut off the 2800 rpm motor as it will drive you nuts.
On a fast boat where the engine is way in the back it's great.. just not on a trawler.
Even on the Dashew boats if I real his typical speed curves he runs @ 1600/1800.
I have never seen a engine in any car, boat, airplane where a 4cyl. smaller higher rpm ( to get equal power ) is as smooth as a 6cyl. motor.

If you are trying to get a less costly initial investment for a close cruising boat the 4cyl. wins.

HOLLYWOOD

Here...add a picture of an Albin for flare...known for being a much less wet "trawler".

But I'm sure it will be ignored.

 

[FF]

>The JD is pulling about 20% more HP per cylinder and possibly 30% more based on CID. The 4 will be rougher than a 6, balance shafts can only do so much.<

Rated or advertised power is where sport fish operate , trawlers poke along at 25-50 hp so the HP rating difference would have little to do with engine life.

A small turboed electric injection engine would in theory be more efficient , BUT the price of perhaps being dead in the water does not appeal to me.

Sea Tow is about $150 a year and I doubt even on the 1000 hour loop run the electric injection would save $150 worth of diesel.

KISS is always my first choice , mechanical diesel, mechanical fuel pumps , Murphy mechanical gauges , .hyd windlass hand held GPS.Mechanical toilet

Sad that the Detroit 3-51 and 3-71 were killed by the air police , as starting with a balanced engine is easier than spinning balance shafts or adding 3 cylinders to find a useful truck donor engine.

KISS allows the voyage to continue , and repair whatever anchored or dockside , with out the need for a tow vessel.

 

[Capthead]

My point about heavier engines was not explained that well. I should have said thicker walled engines which means a heavier engine. My Fords are wet sleeve too. They were made in Dagenham, England and the smallest of the Lehman series marine diesels. I think my 6 cyls are only 337 CI or there abouts. The Dovers and Dorsett engines are bigger displacement and dry sleeve.

Yes I have a wet ride in cross winds and seas but the advantage of the near plumb bow is I go over wakes and waves splitting them to an extent which smoothes the ride.

I was in the outer harbor of the LA Harbor and a 50+ foot Bertram ran across in front of us pushing a huge wake. Probably doing 16-18 kts. I had two friends on the bridge with me and when we got close to that huge wake they both grabbed hold of the rail. The boat hardly moved as we crossed it and they both had that look of astonishment and commented about the boat and it's ride.

 

[Nomad Willy]

My point about heavier engines was not explained that well. I should have said thicker walled engines which means a heavier engine. My Fords are wet sleeve too. They were made in Dagenham, England and the smallest of the Lehman series marine diesels. I think my 6 cyls are only 337 CI or there abouts. The Dovers and Dorsett engines are bigger displacement and dry sleeve.

Yes I have a wet ride in cross winds and seas but the advantage of the near plumb bow is I go over wakes and waves splitting them to an extent which smoothes the ride.

I was in the outer harbor of the LA Harbor and a 50+ foot Bertram ran across in front of us pushing a huge wake. Probably doing 16-18 kts. I had two friends on the bridge with me and when we got close to that huge wake they both grabbed hold of the rail. The boat hardly moved as we crossed it and they both had that look of astonishment and commented about the boat and it's ride.

Cap haha you have such small engines you must need to over work them to go 7 knots. Kidding aside I looked at an old wood boat that had that engine and considered it ti be an advantage. Does the Dagenham engine have the hot #6 cyl cooling oroblem? Should be the same but being wet sleeve could be different in the overheating issue too.

The plum bow is good. It lengthens the WL for more pitch stability and has the potential to deliver more speed w her long keel. And re what Hollywood said it produces a narrower entry angle. But your wave splitting capability's are due to the steep deadrise in the forefoot not the narrow entry that's not narrow. Can't have a boat that wide w full width chines far fwd and have a narrow entry. Simple geometry.

Re the Bertram wake I suspect that was that you crossed that wake at just the right angle. I'm amazed at times even w my little boat.

I'll say one thing in favor of heavy engines. If you have light internal moving parts and heavy parts like flywheel, head, block ect the reciprocating parts won't be able to shake the whole engine as well/much so less movement gets to the engine mounts ..... less vibration. But that point hardly holds much if any water as most engines are about the same regarding the relative parts of the engine (except those w aluminum blocks, heads, exhaust manifolds ect) and there are VERY few of them in our midst.
Generally bigger heavier engines have heavier moving parts as well and all those heavier reciprocating parts shake the engine more. I once heard an Easthope (very large 1 cyl engine) powered boat somewhat close and felt sorry for the bottom of the boat and the pounding it was getting.

 

[Nomad Willy]

I guess you missed the point... look at the flair of the GB VS, the Selene in the attached photos.. almost no flare at the bow of the GB vs substantial flair on the Selene.

The added flair:

1. adds reserve buoyancy as the bow goes into a wave
2. deflect spray away from the boat vs allow it to climb the hull

I have yet to be on a boat with a high rpm motor that I would want to stand over for any length of time. I have a friend with one of those cute Ranger tugs that you cannot wait to shut off the 2800 rpm motor as it will drive you nuts.
On a fast boat where the engine is way in the back it's great.. just not on a trawler.
Even on the Dashew boats if I real his typical speed curves he runs @ 1600/1800.
I have never seen a engine in any car, boat, airplane where a 4cyl. smaller higher rpm ( to get equal power ) is as smooth as a 6cyl. motor.

If you are trying to get a less costly initial investment for a close cruising boat the 4cyl. wins.

HOLLYWOOD

Hollywood I see your picture of the GB head on and I remember psneeld posted the same kind of pic and it has the same misleading effect. Good move on your part from an argumentative standpoint as it actually LOOKS like the featured GB has a narrow entry. But as I think I said any boat w a big full bow wave has a big full bow that creates it. And both the Selene and the GB have big full bows that push the water aside abruptly .. not gently like dwatty's (David's) previous boat. I think wer'e going apart here because you are thinking of trawlers w even wider entry angles than the GB. And you could probably take a picture head on of a Great Harbor that would look like it had a narrow entry too. And I'd rather not talk about flare but your picture shows little of the GBs entry and mostly of her flare.

Re small engine noise I think you are used to big engines under light load and comparing them to small engines under heavy load.

 

[psneeld]

I wonder how a steep deadrise can widen so quickly to a relatively blunt bow?

Oh yeah...I see it in the Albin picture...the chine and the entry change by widening the beam at a different rate...those designer's...what kidder's not following simple geometry...

 

[rjtrane]

Chris. The single pod boat your read about was the one I drive. The ZF pod they used was the 2500. - an aluminum alloy pod (similar metal as I/Os). Not at all suitable for 40' plus semi semi displacement applications.

In fact, neither the IPS nor the Zeus is designed for semi-displacement. I do recall seeing a press release saying that one or the other is developing a unit for slower speeds and may work in the size and speed range you're thinking of. But in twins , triples or quads.

I'd like to see someone develop a slant shaft gear box that would support counter rotating props. Might be an efficient alternative to pods.

You may have gathered by now that I am a fan of:

1. Modern, computer-controlled diesels
2. Counter rotating props.
3. Pods.

I get a kick out of the number of aficionados of out-dated technology. Who cares how much it pollutes nor how inefficient these antiques are. Even love how heavy these old motors are. Today's designers work overtime to get weight out of a boat. No one admits that you can't even buy these old motors anymore.

 

[Northern Spy]

I get a kick out of the number of aficionados of out-dated technology. Who cares how much it pollutes nor how inefficient these antiques are. Even love how heavy these old motors are. Today's designers work overtime to get weight out of a boat. No one admits that you can't even buy these old motors anymore.

Indeed!

 

[Art]

I'd like to see someone develop a slant shaft gear box that would support counter rotating props. Might be an efficient alternative to pods.

Hummmm - I know developing this is not as easy as tying our shoes, but, why don't engineers tackle this? It’s design must be attainable!

Sounds a good idea! That along with rigid protection apparatus for shaft and blades (single or twin screw) might become a bullet proof method toward a way for relatively low cost high efficiency marine propulsion that could be used in new boats as well retrofits for existing trawlers (pleasure boats)... no matter the hull design.

 

[CPseudonym]

Hummmm - I know developing this is not as easy as tying our shoes, but, why don't engineers tackle this? It&#146;s design must be attainable! Sounds a good idea! That along with rigid protection apparatus for shaft and blades (single or twin screw) might become a bullet proof method toward a way for relatively low cost high efficiency marine propulsion that could be used in new boats as well retrofits for existing trawlers (pleasure boats)... no matter the hull design.

There's no market for retrofits Art. No real market anyway. Anyone with the wherewithal to retrofit modern engines and drive trains to old boats would build or buy new. Those interested in refits AND have the cash are as rare as hens teeth.

Didn't someone in Stockton with your same make and model Tolly recently dump close to $100K into diesel power?