How difficult to convert this engine to variable speed? [Archive]

CDK

10-31-2009, 03:51 AM

This is an excellent engine for a small boat. As Apex1 wrote, it was configured to power a generator, which means two things.

The throttle lever mechanism (completely external) has the adjustment screw set at 3600 rpm for 60 Hz operation. It can be adjusted with a screwdriver.

The spring length and diameter which determines the governor characteristics (also external) is chosen to give precise load control between 3000 and 3600 rpm. In the range between idle and 3000 rpm it is less efficient, so the engine behaves more like a gasoline engine. For a boat that should be no problem.

gonzo

10-31-2009, 07:38 AM

Gas engines are controlled completely differently from diesels. There are gas engines with governors to keep a constant speed. Diesels, unless electronically controlled, use a centrifugal governor. It is spring loaded and the tension of this spring against the centrifugal force of the counterweights spinning balances at a certain point. That is the RPM the engine will run at. In a generator, the spring tension is fixed. For other applications, the spring is connected to a cable or lever to which can be adjusted manually.

Homefront

10-31-2009, 10:02 AM

Gentlemen,

Thank you all for the replies.
I'll bare my soul and tell you what I have in mind for this engine and would appreciate any thoughts..
I fish the waters around the NJ coast, for blues, stripers, flounder, etc. I have a small skiff for back bay and river fishing, and my friend has a 20' deep-V that we use for coastal.
I'm tired of pounding, tired of bad slow-speed behavior, tired of noise, tired of big fuel bills.
I'm also the one who encourages us to go out when the water is a less than comfortable 3-5'; we've had waves roll over the foredeck and up the windshield more than once when fighting back to the dock at 5 or 6 knots, against the wind.
I want a boat with a 2-person pilot house, as well as a dodger for gear and a portable toilet, and a self draining deck sole.
I'm considering the Atkin Sallie Hyde http://www.boat-links.com/Atkinco/Utilities/SallieHyde.html, http://www.boat-links.com/Atkinco/Photos/SallieHyde/index.html and I might arrange things sort of but not exactly, like this:

Homefront

10-31-2009, 10:06 AM

As to the engine, what are your thoughts on alternator, exhaust, cooling, transmission, propeller selection?
I'm fishing for things I don't know or may not have occurred to me ;) .

gonzo

10-31-2009, 10:10 AM

All those parts should be standard. They are plenty of those engines around. The original transmissions, are a Japanese built Hurth. You may find a US made transmission for cheaper.

apex1

10-31-2009, 10:33 AM

Are you planning to put the Yanmar into this (beautiful) Atkin design?
That engine has not enough "beef" to propel such boat uphill!

Homefront

10-31-2009, 11:00 AM

That's the idea.
Atkin recommends a 12 hp slow-speed engine. You think this high-speed unit would be insufficient, regardless of propeller choice?

apex1

10-31-2009, 01:40 PM

You gave the answer already! Prop choice!

These wonderful boats are heavy and turn relatively big props. You need some torque (displacement) to turn them.
You will have some 8 horses (just guessing) left at the prop, when your done with the setup. Assuming you set her at 3000rpm max. to have at least some years of service life, not weeks. But there is not much torque to turn a big wheel.
Atkins recommended that due to the fact that these engines were displ. monsters at 1,5 or 6 even 10 liter.
This little Jap is the opposite at just 0,57 liter, though a fine engine, no doubt.

Maybe we can compensate a bit by using a high ratio gearbox. But would´nt it get cheaper to find a Sabb or Lister Petter with all the gear, second hand?

Sorry I´m not happy to have rained on your parade, but I think better the bad news now than later when all the stuff is bought.

Regards
Richard

Homefront

10-31-2009, 02:20 PM

Apex,

Not raining on my parade at all - I asked for honesty from people with more knowledge and experience than I have. I thank you for your input!

This engine is promising as well, though not a diesel:
http://www.marineengine.com/cgi-bin/suite/classifieds/classifieds.cgi?request=detail&id=15835&category_id=107&sub_id=1039&variable_file=gasinboards.variables&group=1&set=1&position=6&total_count=22&website=default&prev_action=display_sub_list&session=4aec7f253a533b30

apex1

10-31-2009, 02:44 PM

If it´s not a Diesel it must be a steam engine! If that is negative, it´s not in a boat.
That is my philosophy. I know though there are other opinions. Fact is I do´nt know anything about marine petrol engines, and would never put one in a boat. But that is a biased opinion, sure.

Are´nt there other boats of comparable size in your region? Do´nt know what Pa means (and even if....)

Regards
Richard

Submarine Tom

10-31-2009, 03:36 PM

Homefront,

A small diesel is the way to go here...

Tom

Homefront

10-31-2009, 04:03 PM

Pa = Pennsylvania. I'm about an hour north of Philadelphia.

You are in the same camp as my friend, who says he would never have a gas inboard, for safety reasons; his logic makes diesel my first consideration.

25hp may be a better starting point for this hull. Then again, perhaps another hull design is out there that is able to fish up to 4 people, handle rough water, provide some level of comfort for all day trips (this rules out something like a Grand Laker canoe), yet be efficient enough to be driven by such a small diesel at displacement speeds.

Perhaps a design like this would be more easily driven: http://www.boat-links.com/Atkinco/Utilities/FishHawk.html. I doubt that a conventional pilot house would be a good idea for this hull, as it looks like it has fairly low initial stability - the hard chines on the Sallie Hyde gave me more confidence that a small house would not cause unacceptable motion. For the FishHawk, a large center console, with a roof and aluminum framework for a soft enclosure might be light enough to work well, with the aforementioned dodger. The hull could be strip built, which would be lighter due to less framing, and I'm thinking that the rounded hull would also drive more easily. I'm not necessarily married to Atkin designs, but their online catalog is handy for ideas.

apex1

10-31-2009, 05:25 PM

Haha..
do´nt take that too serious mate. There are several hundred thousand people around with petrol engines, most of them are still alive! Thats just my personal opinion. (though I am very straight on that! I refuse to build a boat with a petrol engine)

We should first focus on your requirements is my suggestion!

How heavy the payload, how many people max?
How long the max. distance from port (range / speed)?
How serious the weather conditions in worst case?
Apart from the wheelhouse do you need a "cuddy" or a place for a loo?

I love the old Atkins plans (most of us here do), and sure the boats you linked to are able and rugged workhorses, bringing you back safe even in severe conditions. But.....
I have real difficulties when it comes to substantial changes in the original design.
A house for sure is such a change.
Both boats are definetively able to cope with 5 adults standing upright (how they can is another issue), without being in any danger, but no designer reckons they do so in a blow.
So, I do´nt know if it is a sensible decision to put a house on them. (with, I do´nt know, I mean exactly what it says!)
Maybe better we find a design that was developed with a house?

The Yanmar, as mentioned, is a nice engine, and could fit your needs when connected with a sufficient reduction ratio gear. That is not completely out of the race I think. But you must be sure to find all the missing stuff at reasonable prices! What they are going to sell you there is just two pistons and a housing. Flywheel, bell housing, alternator (pulley?), exhaust, cooling, etc. all missing. And we know, that a engine built by spare parts is about 6 to 8 times the price of a complete one.
Take that into account before you get too enthusiastic about this bargain.

Now lets start at the bottom: requirements?

Regards
Richard

Homefront

10-31-2009, 07:44 PM

Very well - the requirements as you listed them:

PAYLOAD: 2-4 people, + - 200lbs of gear; coolers with ice, bait, poles, tackle boxes, spare clothes, tools, etc.
Too long to list would be the standard boat equipment (anchors, batteries, extinguisers, etc), which would add up to an additional 2-300 lbs.

AVERAGE TRAVEL: 25-30 miles round trip. Fishing and moving, that's about all we cover in a day.

WEATHER CONDITIONS: We will go out in 3-5' seas, and have been caught out in worse. If there is a small craft warning we will still go out, provided the NOAA is reporting improving conditions. We often leave the ramp before sunup, or late afternoon and fish until 10-11pm.

ENCLOSED SPACE REQUIREMENTS: Some kind of pilot house. Also, we would need a "privacy" space, which I believe could be accommodated by a dodger with a curtain. We also need storage for the above mentioned items.

CDK

11-01-2009, 03:40 AM

The Yanmar, as mentioned, is a nice engine, and could fit your needs when connected with a sufficient reduction ratio gear. That is not completely out of the race I think. But you must be sure to find all the missing stuff at reasonable prices! What they are going to sell you there is just two pistons and a housing. Flywheel, bell housing, alternator (pulley?), exhaust, cooling, etc. all missing.

Too many negative waves Richard. The little engine comes with a real flywheel, starter motor, double pulley, water pump and a very interesting light alloy silencer.
That last item could mean that the engine was configured for a silent running generator like the completely encapsulated ones for yachts.
It does need an alternator and a heat exchanger, but these parts need not be Yanmar. Anybody who can cut and weld sheet metal could make some sort of bell housing that accepts the SAE flange of a small gearbox.

apex1

11-01-2009, 04:28 AM

Too many negative waves Richard. The little engine comes with a real flywheel, starter motor, double pulley, water pump and a very interesting light alloy silencer.
That last item could mean that the engine was configured for a silent running generator like the completely encapsulated ones for yachts.
It does need an alternator and a heat exchanger, but these parts need not be Yanmar. Anybody who can cut and weld sheet metal could make some sort of bell housing that accepts the SAE flange of a small gearbox.

Hi Cornelis,

that was not my intention to make negative waves!
Sure that was meant for a generator as mentioned several times. The alloy silencer I did not see though. (did not really look at the picture)
But: No alternator, radiator, fan blade or air cleaner. Belt-driven water pump with no belt or tensioner
and bell housing is left. Hence I said "be sure to find all the missing stuff at reasonable prices!" That must not be Yanmar, you´re right!

Thanks for correcting that!

Homefront
will come back later on the requirements.

Now. The payload comes out at about 600lbs ? How much is the catch?

Range is not a drama, being just about one hr from port, did I understand that right?

ENCLOSED SPACE REQUIREMENTS: Some kind of pilot house. Also, we would need a "privacy" space, which I believe could be accommodated by a dodger with a curtain. We also need storage for the above mentioned items.

That all together will hardly be possible in one of the Atkins designs we would like.

Any other boat suggestions / ideas ?

Regards
Richard

Homefront

11-01-2009, 09:36 PM

My reasons for starting a thread concerning this engine are these:

I want my own salt water fishing boat.
Economics dictate that it be economical to both build and operate.
The realities of coastal sport fishing demand that it be dependable, seaworthy, and equipped to stay out for 8-12 hours.

This hull, equipped with a dodger, as well as a center console with a canvas enclosure, may be more in line with what I need at this stage of my life:
http://www.batritningar.se/default.aspx?Language=EN&Currency=SEK&Page=BoatplansDetails&Id=18

apex1

11-02-2009, 08:36 AM

This hull, equipped with a dodger, as well as a center console with a canvas enclosure, may be more in line with what I need at this stage of my life:
http://www.batritningar.se/default.aspx?Language=EN&Currency=SEK&Page=BoatplansDetails&Id=18

When dodger and canvas enclosure are fine for you, then the Sallie Hyde will be the better choice I think. That boat at least has proven to be a good one in your waters.

The Atkin boats are very nice and valuable designs, but do not underestimate the cost and time to build such "oldtimer". If your intention is to save money, you´re probably better away with a second hand boat. Like the one you have shown in the first picture.

When you think the joy of building is part of your plan, then go for that. But at present the homebuilt will be above the cost of a good second hand boat.

What do you think?

Regards
Richard

Homefront

11-02-2009, 10:05 AM

Oh yes, building is part of the plan!
25 years ago I was looking for an aluminum boat to use in NJ estuaries and the Delaware River. Money was not the issue then, but every time I found a used boat in the paper it would be sold before I arrived to look at it.

I stumbled upon the Glen-L catalog. Boat building hadn't even crossed my mind, but I ordered plans and built a 14' flat bottomed skiff with which I was hugely satisfied. Reading the catalog (more of a book really) I started envisioning the uses each hull type could be put to and why they were suited to those uses; what they could carry, how they behaved in different sea conditions, what kind of propulsion systems suited them. As my new appetite grew, I fed it with the writings of John Gardner, Pete Culler, Howard Chapelle, Phil Bolger and of course, Wooden Boat Magazine.
I've built 4 more boats since then, all ply-epoxy skiffs of different sizes/uses, learning as I went. I found out right away that being a boat builder and a carpenter (which I was then) required very different knowledge and techniques.

If I weren't supporting a family - paying for college, a mortgage, cars, insurances and all the other family man responsibilities - I'd turn to boat building to satisfy myself in my daily work.

Designs exist that are superior for their intended purposes than what can be found commercially. I balk at having to pay for features put into a boat to satisfy mass marketing requirements. I abhor factory made vinyl ester monstrosities (such as the Grady my friend owns, that we fish on) and the waste they present their owners and the environment in their construction and fuel use. I believe in efficiency, grace, utility, and art in boat design. It's rarely found in anything mass produced.

So yes, I will build my next boat, to satisfy many needs.

The boat in the first picture resides somewhere in the UK. American boating has not evolved much beyond blasting around in gas-guzzling planing hulls, so boats like the one in the photo are super rare to nonexistent here. If I want it, I must build it.

apex1

11-03-2009, 05:17 AM

Oh yes, building is part of the plan!

I've built 4 more boats since then, all ply-epoxy skiffs of different sizes/uses, learning as I went. I found out right away that being a boat builder and a carpenter (which I was then) required very different knowledge and techniques.
So yes, I will build my next boat, to satisfy many needs.

That makes life easier, you already know what you are in.

So how will the Sallie do with a dodger, a light structure "house" and this Yanmar engine?
That lightweight Jap saves some weight, compared with the old iron pigs Atkin designed her for. That may compensate for the doghouse weight already.
But windage and stability sure are questions to be considered.
She is designed for carvel planking, that makes her a possible candidate for a strip plank method to save some weight, especially above WL, where we need to save.
Have you seen similar Atkin plans? Are you familiar with the "classic" methods?

Are there high ratio gearboxes for this engine around?

More questions than answers of course.

Regards
Richard

TowmanDoug

11-03-2009, 11:31 AM

For any one who is interested in the original spec'd engine, there is a similar, but less costly Perkins engine from the same vendor.

https://www.surpluscenter.com/pages/006.pdf

Bottom of page, center, description suggests an optional governor spring to allow the Perkins to be run varibale spped.

Homefront

11-03-2009, 11:44 AM

TowmanDoug,

Good suggestion, but the PDF brochure doesn't reflect up to date stocking info. A search for that part number on the live page says it's out of stock.
Thanks anyway.

Homefront

11-03-2009, 12:00 PM

She is designed for carvel planking, that makes her a possible candidate for a strip plank method to save some weight, especially above WL, where we need to save.
Have you seen similar Atkin plans? Are you familiar with the "classic" methods?

Richard,

Strip planking her in cedar, probably 5/8 x 1" and glass-sheathed inside and out, is what I was thinking. I'm familiar with carvel or "set works" planking, but the idea of making planes with the needed various radii, backing out planks, is at best unappealing. Besides, she would live on a trailer - not a carvel friendly circumstance.
I could plank her on molds, then strip laminate the real frames adjacent to the molds before I pull the molds out.

apex1

11-03-2009, 12:58 PM

Richard,

Strip planking her in cedar, probably 5/8 x 1" and glass-sheathed inside and out, is what I was thinking. I'm familiar with carvel or "set works" planking, but the idea of making planes with the needed various radii, backing out planks, is at best unappealing. Besides, she would live on a trailer - not a carvel friendly circumstance.
I could plank her on molds, then strip laminate the real frames adjacent to the molds before I pull the molds out.

Something like that, yes.

And having done it that way, you would have some 150 lbs or so saved above WL, then a sandwich made house would be within technical possibilities.
Due to the fact that there is no Atkin left to revise the plans, who will do that? I do´nt feel comfortable without.

Did I understand the post above right? The engine is´nt available any longer?

Regards
Richard

Homefront

11-03-2009, 01:36 PM

The engine is available - TowmanDoug was suggesting an even less expensive alternative - a Perkins - which is, sadly, out of stock.

As for stability; after the boat itself was built, I would do a mock up of the center console/enclosure to simulate the height and weight and do some sea trials before I built the real thing.

Another thing to consider: Atkin provides 2 sets of lines with the plans - one hull designed for 9-10 knots, the other for up to 16 knots.
I assume that the faster hull has less upsweep to the chines aft, providing more bearing and bottom for prop thrust so she doesn't dig a hole. This has me wondering if the faster hull would also provide more initial and reserve stability.

Methinks it's time to order the plans and find out!

apex1

11-03-2009, 01:55 PM

Nothing can beat a empirical test....................

Due to your engine choice (and economy), there will be only one choice left, which one to build!?

What was it 55$ or so. I think that is a good and relatively cheap start.

Regards
Richard

Homefront

11-06-2009, 03:35 PM

Perhaps either of these two would be more reasonable for the power:

Devlin Dipper. I would lengthen this hull 2-3' for more fishing space, which I think would also be necessary for an inboard installation:
http://www.devlinboat.com/dipper.htm

Atkin Surprise. I might add 1' to this one, and move the low cabin forward 2'. Then I could add windshield to the aft edge of the low cabin, with some kind of foldable bimini: http://www.boat-links.com/Atkinco/Sail/Surprise.html