Sharpie Schooner 42 with an outboard motor

This is my Solution for an outboard installation on a 42 foot shallow draft schooner. There will be a box covering the outboard that will act as a table in the cockpit. All the cockpit drains will drain in the motor well. Also the outboard can be trun 30 degree either way for improve handling in the marina or tight spot. The outboard that I fitted in the drawing is a Yamaha 60 HP High trust, should be plenty of power!

The floor is 6 inch above the water line. hopefully it is high enough!

On the large rudder there will be step attach to it to provide a mean to get back in the sailboat, if the is a ''men over board''.

The large centerboard is only ballasted to make sure it drop, The ballast is provided by a flattiron keel, about 5000 lbs of lead in a metal shoe. The other 3000 lbs of ballast will be internal to the sailboat. Draft centerboard down is about 8 feet, centerboard up around 3.5 feet.

I also incorporated a feature for the centerboard will be able to be pull out from the top of the sailboat by using both mast and 2 halyard to raise it out. This way maintenance can be done without the use of a crane to drop the centerboard.

Also to bring more light in the sailbaot, the centerboard trunck will incorporate large window (plexiglass) on each side of the trunk. Those window will allow light to come in from the centerboard **** and they will also be removable to make any maintenance on the centerboard.

Will I ever build it? Don't know yet, but I am having fun drawing and designing it!

Go ahead all the Boatdesign GURU, I want to hear all your comments! You might have something that I did not think about or should incorporate.

 

Where is it better than proven stock plans ready to the last gaiter button for a small price¹ available on the market ?

¹ You can't afford mistakes by building of DIY plans for what most of the pro's proven stock plans will cost you, this apart from the time you'll still need to develop the plans further, while in the same time you could build a good part of a proven boat.

Yamaha goes till max 50 HP in high trust, and since recently Suzuki goes till max 60 HP in high trust outboards.

The tilting outboard eats a lot of cockpit space, and also needs a large slot in the bottom which generates a lot of resistance in the water.

Both of these issues would be bettered by a vertical lifting outboard, like e.g. on the Norwalk Islands Sharpies of 26' and up.

Good luck with the project !

 

I haven't really looked at outboards that much, but I'm surprised there would be one geared for a displacement hull. I think you would be better served with an electric drive / battery bank / generator.
Cheers,
Mark

 

@Angélique, Yamaha T60 high trust, check the link below, probably a 40hp or 50hp would be sufficient but to make sure there is enough room in the coxkpit I used the biggest motor. I also think that large cockpit are good for confort but if they get filled with water it can become a problem! This solution gives enought room to walk around, brace yourself when sailing and act as a table.

T60 High Thrust | Yamaha Motor Canada https://www.yamaha-motor.ca/products/details-build-price.php?model=4314&group=OB&catId=123

The design of this sailboat is not mine! I bought the plan from Rueul Parker for the Terrapin 42 and as a hobby I am redrawing it in 3D on Fusion 360 with the intention of maybe going ahead with the built if I am crazy enough! Mainly it is a Rueul Parker design that I modify here and there to my belief are some improvement to the original design.

First modification, I like better to have a transom hung rudder, more accessible for repair and I can put step on it. I also think that the rudder area is better compared to the original design. I also used a thicker foil section to keep the flow attach at higher angle of attack. The reverse swept angle of the leading edge of the rudder will also help to have less flow separation at the tip, the flow is directed upward instead. Lastly and more importantly the rudder looks cool!!!

Second modification is the cockpit arrangement, to accept a single outboard motor. I am also considering diesel saildrive, or a Torquedo electric pod. Price, fuel efficiency, ease of repair, manoeuvrability, when in the raise position no drag. Outboard areare rea hard to beat! There are cons of course, like the fuel is more dangerous, ventillaton of the prop, but where I located the engine I don't think it is a problem. The new outboard 4 stroke are hard to beat value wise. I price a Yamaha T60 high trust, 8250$CAN. I price a full Beta saildrive 38HP, 18 850$CAN!

Third, the sail plan is modified a little bit to better locate the COE and the CLR. The original design seams to have way to much weather helm. I also wanted a single jib.

Otherwise it is pretty much the Terrapin 42 from Rueul Parker with the optional Lead Flatiron Keel as an outside ballast.

 

@Angélique

Forgot to mention that you are right about the large slot in the bottom. This is were the engineering aspect will get into play. I need to figure out a simple solution to close this gap when the motor is in the raise position and when it is in the lowered position for motoring. I was think of using thick rubber flap that are on spring loaded hinge. Not sure yet but there is always a solution to a problem. This is the challenge of it!

 

You don't seem to be working from a well defined set of goals, established in an SOR. The SOR will help keep you focused on what is required and the frivolous stuff, like see through centerboard cases can get easily tossed over the side, if only for practicality sake. Make a reasonable SOR and work from there. Where's she going to sail, sea state condisions in these areas, tankage requirements, electrical requirements, plumbing, speed and range targets, costs, build site, transportation, etc.

 

"Second modification is the cockpit arrangement, to accept a single outboard motor. I am also considering diesel saildrive, or a Torquedo electric pod. Price, fuel efficiency, ease of repair, manoeuvrability, when in the raise position no drag. Outboard areare rea hard to beat! There are cons of course, like the fuel is more dangerous, ventillaton of the prop, but where I located the engine I don't think it is a problem. The new outboard 4 stroke are hard to beat value wise. I price a Yamaha T60 high trust, 8250$CAN. I price a full Beta saildrive 38HP, 18 850$CAN!"

You can find 25-30 hsp reefer unit diesels with low hours on them in California (air resource board regs) . Ive actually got one- I never thought to sell it. 2200 hrs 28 hsp... ...$750.00? Japanese surplus diesels $200-$4000 (+shipping)/ 40 - 280 hsp. Low mileage used. $400-500 for a 3 banger from a "premium dealer" $500 shipping. Scrap yard 250 hsp yamaha so you can get a big prop on it- $500. You will save on installation also because no marine certified mechanics will touch it. Probably have to get a handyman for 1/4 of the expense to do it, some fabrication included ... $3250 done deal.

 

The above advice from PAR is good. I look at the long water line, shallow draft, low displacement and can't help but feel this would be an excellent application of an electric motor. Something sized to get you in/out of slips, but then you are sailing. A small diesel DC generator could be well insulated to provide charging of the battery bank. If it was me looking at this design (and it's not ), my SOR would have limited motor range, and focus on sailing. The generator wouldn't be sized to allow you to motor all day. This equipment is becoming mainstream - one example is below. I'd be looking seriously at this if we were starting from a clean sheet.

PMAC 15kW Cont. / 38kW Pk. Liquid-Cooled Motor Drive System 72/84V 550A - Marine PMAC Kits Liquid Cooled - MARINE https://www.electricmotorsport.com/marine/marine-pmac-kits-liquid-cooled/pmac-15kw-cont-38kw-pk-liquid-cooled-motor-drive-system-72-84v-550a.html

 

I agree with the electric motor, especially small 3-5 hsp. She can put that directly on an engine damaged 10 hsp longshaft. SOR sounds like "buisness plan" to me. I'd rather be cruising.

 

When going for electric propulsion with a diesel genset then you can also have the juice to Cook + Oven + BBQ + Warm Water + Cabin Heat + AC + Fridge + Freezer + Vacuum Clean + Computer + All on board Electronics + Communications + Electric Tools + Washing Machine (a mini ?) & Dishwasher (?) + Water Maker + Everything else that needs energie on board, while you only have to carry and store one fuel for this.

You probably don't need or want this all right now, but once an ample electricity source is on board you can easily expand the use whenever the need or the desire arises. While a combustion engine that's mechanical connected to the prop shaft only has a relatively small alternator which is almost only producing juice during the scarce auxiliary propulsion time, so it's impossible to think of general use of that for now or in the future. While at the same scarce auxiliary propulsion time a genset can have the capacity to charge the battery bank much quicker for later general use.

And you can also charge by solar panels and a wind generator, which options will further improve over time, so that's easy to update at replacement time, so the diesel will near fade out in a few decades, that's when you anticipate at the time of the first installation of auxiliary propulsion.

 

Yes you're right Valery, I just saw Yamaha now also has a 60 hp high thrust outboard, but it's a tickled up version of the longer existing 50 hp version. So you'll need to expect a bit shorter service life when you draw that 20% extra Hp out of her often. Also service live will be shorter when she's almost always near idling. And at near idling the alternator won't produce much either. So when going for an outboard, then best buy what you need with no more than a reasonable reserve on top of that.

I've just compared the T60 & T50 specs, and I've underlined the only difference there.​

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↓ 5 × T60 - - (click the below images to enlarge, and click again to shrink, each horizontal row is just one picture)


↓ 5 × T50


Note the chosen prop on the T60 vs T50 needs to be different for the same boat, that's if you want to have the option to transfer that 20% extra power to the water, check the available prop options for this.

 

@PAR

Yes I have SOR established already.

1. Cruising and sailing from Montreal, Canada, St-Laurence River, the canals, Lake Champlain, The great Lake area, maybe eventually the great Loop. The ICW, down to the caraïbe. When the weather permits it crossing to the island of Cuba, sailing around the island, island hopping in the Caraïbes, If everything is still going well at this stage sailing the coast of south America.

2. The sailboat needs to be large enought for a family of 5, my wife, me and 3 kids.

3. The least system possible onboard, ex.: puck led light without wiring, etc. Simple navigation station, VHF, Open source chartplotter "Open CPN" "Navigatrix". etc.

4. Being able to single hand the boat when the family wants to go baxb home for vacation from the vacation!!!

5. Since it is a shallow draft Sailboat the stability curve is limited compared to a full keel sailboat, there is a need to think differently about safety. Water tight bulkhead, that can be close and when filled with water will not sink the boat. If caught in bad condition when on a short crossing, the stategy would be to raise the centerboard up, heaving to, going inside the Sailboat and closing all the hatch and bulkhead doors. Waiting the strom to pass, this is in an extreme emergency, I will try to plan sailing days around good weather window.

4. Set up the sailboat to be as self sufficient repair wise as possible. Simple schooner rigging with blocks, etc. Centerboard that can be maintained without the need of a yard. It can be raise out of its slot with both mast haylard. It can also be serviced from the plexiglass window in the centerboard case. The window is only starting at around 4.5 ft above the centerboard box to the about 6 foot high.

5. Target cost, 150 000$CAN

6. Building site will be at my shop. I have enought land to build a temporary shelter.

7. For fuel tankage wise, it will be as much as possible to fit under the cockpit floor. For coastal crusing and short island hopping it should be enough.

8. Also I try to keep all the engine, fuel out of the cabin area. I hate the smell and the noise inside the cabin area.

9. There is more SOR, but I need to go take care of my family.


Thank for all the good inputs

 

The engine box needs to be sealed from the cockpit and vented with a bilge blower. Just assume that all of the OB exhaust will, under some conditions, return to the well. So nix the drains into the well. Supply air to the box should be routed from outside the cockpit as well. The box design causes some minor trouble with fuel line routing, but not insurmountable. Just give yourself plenty of dead space in the box. You'll want to fashion a plug for the bottom of the well, probably in two parts. Use a longshaft motor so that you have maximum height difference when it pivots. Mount it so you operate in the full trim down position to maximize height difference when it pivots. And you may not be able to get it dead level either. These motors just don't pivot enough to work in a well unless you push everything to the limit. Having said all that, slam the motor as low in the well as you possibly can, that is the point of the preceding three sentences.

Just to be clear, these arrangements are a damned nuisance under the very best circumstances. A 15 hp diesel and shaft installation would be a huge improvement under all conditions. I tend to burn about 0.3 gph in my 38'er when under power, which suggests that most of the time, I'm ticking along with about 3 hp at the shaft. I'd suggest starting out with a 20hp OB and see how that goes. The 16 amp alternator on the 60 isn't the best way to provide house power and recharging anyway. You'd still want a little genset on a 42'er.

One other observation. Traditional sharpie rudders didn't have to operate in reverse. That rudder on the Terrapin will be impossible to manhandle while backing up, and will be seriously affected by the prop at modest forward motor thrust. I'd redesign it for motoring, and/or use worm gear steering to zero the helm feedback.

 

I'm still wondering why a tilting outboard in a well should be preferable above one on a vertical sliding bracket that's also in a well.

Besides the above named cockpit space advantages, a smaller well also means it costs less of the scarce aft buoyancy.

See also Rodger Martin's Presto 30 outboard well with a vertical sliding bracket. When down a fairing above the anti ventilation plate closes off the slot around the outboard's leg for efficiency when motoring. When the outboard is vertically raised by a tackle then another two part fairing closes off the whole slot below the raised outboard's skeg and so makes for a flush hull. Note also the place of the outboard well on the Presto 30 . . .

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P.S. - The outboard and the forward plus off center well are shown at ± 1:11 to 2:17 in the video.

 

@philSweet

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You are right about this one I need to think more about this solutions basically to protect myself from carbone monoxide intoxication, right?

The rudder is planned to controlled with a wheel steering mechanism, with the possibility to installed a tiller for emergency. The wheel will be located in forward cockpit location at the cabin bulkhead on "tribord". The torque from the rudder when in reverse should be controlled by the wheel mechanism.

The rudder is around 10% balanced. should be fine, most Sailboats have a prop mounted in front of the rudder, why this time will it be more of a problem?