outboard motor well?

[captain charlie]

I will be ordering the kit in a few weeks, but already have the plans and manual. I decided to build the spars first as I will be limited in room in which to build the boat. So far so good, as I am finishing up on the bowsprit. I've been reading the various topics discussed and the motor question seems to come up quite often. Has anyone considered a motor well with the motor fixed and using the rudder for steering? I would think that perhaps the motor ( a 2-3 hp) could be lifted partway up when not in use. Anyone have any thoughts on this? Incidentally, John, I took your suggestion and attended the clc class in Port Townsend last June, building the Passagemaker Dinghy. Its fun to sail, but I really enjoyed building it - hence, the Pocketship. My wife thinks I'm nuts. Captain Charlie

[Bflat]

I've wondered about a well too. I'd be very interested in if that would be practical. I hope someone offers advice on this.

[John C. Harris]

>>>>Has anyone considered a motor well with the motor fixed and using the rudder for steering? I would think that perhaps the motor ( a 2-3 hp) could be lifted partway up when not in use.
>

Depends on what you mean by a "motor well." I've seen at least two PocketShips with the outboard hung right on the transom, which requires that you cut a big notch in the transom and transom skirt. The advantage to this is that the motor and its controls are a few inches closer to the skipper---you don't need to lean as far astern. The disadvantage of this location is that the rudder can now swing into the propeller blade. I consider this a critical disadvantage. I've owned two sailboats where this was possible; both acquired deep gouges in their rudders. Murphy's Law requires that no matter what gadgetry you deploy to try to hard-lock the rudder from hitting the prop, at some point it won't be in place when it needs to be. Also, limiting the swing of the rudder while you're under power is a bad idea. The outboard is usually running when you maneuver in confined spaces, not an occasion when you want limited rudder movement.

If you sling the outboard on a transom bracket, as it is on mine, then the rudder swings freely at all times. It's also a zillion times easier to mount a bracket than it is to carve up the transom. The disadvantages are that the outboard is further from the center of gravity, increasing the moment of inertia slightly, and that the outboard is a little more exposed.

Some big sailboats have the outboard mounted in a well, forward of the transom. This is not practical in PocketShip. There isn't enough room in the cockpit, the buoyancy loss is too great in a boat this size, and the parasitic drag from the opening in the bottom would be serious. (The lower unit of the outboard dragging in the water can erase 25% of PocketShip's speed.)

You can buy an outboard bracket off the shelf. I built mine: http://www.clcboats.com/shopcam/20090824.html

I made my bracket about a half-inch too short, so the lower unit just touches the water when the outboard is stowed. No real drag under sail, but lubberly. Another half-inch and the lower unit would lift well clear of the water. We can all agree that engines on sailboats are an eyesore.

PocketShip Outboard.JPG (1.21 MiB) Viewed 6332 times

[tattoo]

There's no "best" arrangement for auxillery power for PocketShip. It depends on multiple factors, but mainly regarding where you sai (river, bays, harbors, etc.) and distances. If winds are fickle and tides strong and you expect to cruise overnight at some distance, then you probably need reliable reserve HP =/> 4 or 5. If you are daysailing nearby, then < 2 or 3 would be quite enough.

For the > 4 or 5 hp, I favor a transom cutout rather than the bracket. I ordered a bracket where the website catalog said it was rated for a 4-cycle 25 hp, but on arrival the box said not for use with 4-cycle engines! Not wanting to go against the manufacture's recommendations, I sent it back. Four-cycle engines have a lot more vibration (then 2-cycles) because of the reverse torque of each compression stroke spaced between each power stroke. So, I decided to mount my Tohatsu Sail Pro extra long shaft 6 hp on PocketShip's transom. Both are ugly (compared to an inboard or well mount), but I think the cutout is less ugly than the bracket hanging 59 lbs further aft. I stiffened the transom with a 3/4" x 6" piece of ash (the bottom of which sets just at the cockpit deck) that extends the entire beam between the combings. I miscalculated the debth and (after my first sailing season) added about 1.5" across where the cutout was made. That additional height brought the propeller up just enough so that it wouldn't clip the wing on the bottom of the rudder (when all the way to port). On the aft side of the transom (at the cutout) I installed a 1/2" pad the keeps the engine mount from chewing up the (rather) soft transom plywood. It is made of two laminated 1/4" pieces of close-graind maple epoxied together (grains crossed).

The engine mount in the cutout has served well. My first installation included a sliding block on the starbard side of the tiller that limited the rudder from going too far to port and being clipped by the prop. When not using the engine, the sliding block could be moved forward, permitting unrestrained rudder movement. But now I have a "stearing linkage" that allows unrestrained rudder movement at all times, even when using the engine. This should allow much better directional control going into/out of slips and close anchorages. The linkage can be disconnected and stowed in just a matter of 20 to 30 seconds. See my posting of 1/15/12 re "Cruising Auxillery." She will undego "sea trials" within the next few weeks and I'll report the results.