Sailboat Electric Outboard Motor Conversion - Cape Dory 27 Refit Part 4

We convert this Cape Dory 27 from inboard diesel engine to dual function outboard well that will hold either the Epropulsion Navy EVO 3.0 electric outboard or the Tohatsu 6hp Sailpro gas outboard. While we're at it we also replace the rotted core in the cockpit footwell. When the owner wants to make long coastal trips with frequent motoring he can use the gas motor. Otherwise he can swap it out for the electric motor which will be sufficient when he does not require more than 10-20 miles range (depending on boat speed). In practice we expect he can motor out of port, set sail, and if the boat speed under sail is close to 5 knots then he can recharge the battery using the motor prop for regeneration. If the battery is only partially depleted it could fully recharge on an overnight passage or it may take a couple days if fully discharged. Check the Cape Dory 27 playlist later for updates on the sea trials.

Annapolis Hybrid Marine epropulsion dealer
www.annapolishybridmarine.com

Pros and cons of electric inboard vs electric outboard motor:
With an electric inboard motor it may be difficult to find space for both motor and batteries without placing batteries in lockers that might be useful for other items, an inboard requires a higher sailing speed before regeneration kicks in, the prop and shaft is always exposed to fouling and damage and cause drag under sail at speeds too low for regen to begin and they are less efficient at transferring power from motor to prop. On the plus side, because it is lower and closer to the centerline, an inboard prop will not ventilate (lose thrust by sucking air from the surface) like an outboard can do in choppy waters. The electric outboard can be swapped out for a gas motor if you have a failure of the electronics or plan a long coastal or river trip that requires more range.

Advantages of gas outboard over diesel inboard:
1. Less cost up front and for future maintenance.
2. Less weight and wasted space.
3. Reduced complexity, which makes for easier future motor replacement or repairs. You can take the motor to the repair shop instead of bringing a mechanic and all his tools to the boat.
4. There is no fixed prop to snag fish traps and nets under sail.
5. If the prop ever gets fouled or damaged you just tilt it up and clear it or replace it by reaching over the transom.
6. Sailing performance is noticeably improved by less drag and turbulence once you remove the inboard’s fixed prop and seal off the prop aperture between keel and rudder. The rudder will also become more efficient.
7. You have the ability to swivel motor for side thrust when entering a tight marina slip.
8. An outboard well puts an end to inevitable diesel fuel and oil spilled into the bilge and their odors.
9. The self-contained outboard motor eliminates two more holes below the waterline—no engine cooling water seacock and plumbing or prop shaft in a leaky stuffing box.
10. Because you no longer need to access a diesel exhaust and prop shaft and all the rest, you can now seal off all the cockpit lockers from the bilge, giving you the added safety of collision bulkheads and less chance of flooding.
11. There is no need for a separate engine starting battery and charging circuit. This also makes conversion from lead acid batteries to lithium.
12. The motor does not radiate unwanted heat into the boat all night when you try to sleep in the summer or in the tropics after motoring.
13. A smaller motor has a smaller environmental impact.
14. Even if your electrics go dead you can pull start an outboard motor.
15. Outboard motors have less power loss than inboards, meaning that a 9.8hp outboard is closer in actual thrust output to a 15hp inboard engine.
16. You will become a better sailor by taking more care not to get in a situation where you rely on the inboard engine when you could use the sails instead. The more limited range and thrust of a small outboard teaches you to become a better sailor. You will find that as your sailing skills and experience in passage planning increase, there will come a corresponding decrease in the horsepower you need.

For more info on outboard well construction check:
https://atomvoyages.com/articles/the-...

We can be reached at atomvoyages.com or if you have a classic sailboat and want to share your experiences or have questions on fitting out, consider joining the Plastic Classic Forum at https://plasticclassicforum.com/forum/
I'm a moderator on the forum and answer questions there.

Video editing by Benjamin Whiting. Check out his Cape Dory 30 YT channel - Aboard The Flying Spur:
   / @flyingspur