Outboard Well

[Matthew]

Can anyone let me know the drawbacks of an outboard well? It is on a sailboat, and only used as auxillary. Ive heard a few designers (Bolger, Dias) slate them, but not give reasons (in the text I read).
Can anyone help?
Matt

[PAR]

Outboard wells on sailboats can clutter up the cockpit, If not vented well can rob the engine of good air and make for rough running and stalling, they have a great deal of drag in most designs (not good on sailing qualities) The heat can build up in the area to a surprising amount, complicated additional structure to have this feature adding weight, building time and costs. Working on the engine in this space is limited at best.

Depending on power requirements, any boat needing 10 or more HP should really consider inboards, where a whole new can of worms opens up for the designer and builder, but in general a better arrangement for propulsion.

They do leave the transom clear of bracket hung engines and the weight in the worst spot you'll find to hang the beast. They do operate with a much reduced noise level in a well, they are less likely to get stolen or damaged, then hanging on the transom.

As with all elements of boat design, compromises are made and lived with. Wells have their place, but I don't like them much on sailboats when a trolling motor or kicker can be used then stowed. If the boat has enough displacement to want for some HP then the inboard is the way to go.

I know a guy on Marco Island that uses a 24 volt electric motor out of a washing machine and a couple of batteries to run down the river to the races on the weekend. His motoring time is about an hour 'round trip and the batteries trickle charge 'till needed again the following week. The Atomic4 in this 25'er took a dump and he's saved a bunch of weight by removing it and using the electric brew of his own invention.

[Matthew]

Thanks PAR,
Its a double ended design, which is why we are doing it. She also has a small amount of overhang at the stern, which means the hole in the hull is above the waterline and so less draggy. Am a bit concerned about the overheating, as by necessity the cut out in the aft deck is a close fit.
Its a 2-3HP engine, a 17foot epoxy ply daysailor - about 400lbs weight.
Does anyone else have or know of problems with outboards in wells, like overheating or lack of oxygen?
Cheers
Matt

[Robert Miller]

In general, I would choose to avoid creating a well with a resultant hole in the bottom somewhere... for all of the good reasons stated by others above.... and, it's just too complicated for my simple mind.

In small sailboats with transoms, I favor a stowable small outboard in a purpose built compartment. Hang on transom when needed, and stow when under sail or oar. I've had this arrangement on a boat as large as 26 feet, and liked it well.

In small double-enders, I would rather not have the weight of the engine all the way aft. Also, I don't wish to put my weight that far aft as I shift myself and the engine into position just to mount the thing on "something", - with the resultant reduced stability.

There is a better solution. On such a small double ender, the engine belongs just aft of amidships. Create a dedicated stowage compartment (perhaps under a side seat, somewhere near amidships). An arrangement to extend a mounting board across the gunnels and secured in position is needed. This must be designed for the particular boat, and supported as needed. A plank for this or other mounting hardware should also have dedicated stowage arrangement when not in use. Nothing permanent is in the way of sailing or using oars at any time. When mounted, the engine's weight is where it belongs, and so is yours. Steer with the boat's usual tiller/rudder.

And...(another thread at a yahoo small boat group has recently been disccussing this)... keep the engine small and light. EVERYTHING about that engine then becomes easier, and more handy. 2 HP can do most of what we need on the sort of boats we are considering. I'm afraid the power of fashion has led some of us to believe we need larger engines than can effectively be used! Carrying unused and unneeded horespower just makes stowing and using the engine more difficult, and provides no benefit in return.

Robert

I agree with most of what has been said-but it is possible to have a good outboard well if it is designed in from the start -
a good example is the Joker range of epoxy ply trailer sailers in NZ.the larger 24 ft model has a vertical slide -hoisted by a small block and tackle-that lifts the 10hp motor-it can then be tilted forward and a tight fitting ply "plug"inserted -held in place with turnbuckles-this keeps 99% of the water out.When raised the outboard is in its own locker,lying horizontally fore and aft.
The hole for the OB is right at the stern(about3inches from the transom from memory) and is oblong-in its normal sailing mode the hole is clear of the water (just) but this depends on loading,speed of sailing etc.It is important to have an air hole(2 x3 inch) if you put the hatch cover on.The well is spacious so it does not get hot,has a big air volume and you can fiddle with the motor or lifting system without being cramped for room.
This boat is intended for local cruising in reasonably sheltered waters-has a large rig(big main) a lead weighted cb(about 100lbs)plus about 700lbs of dumpable water ballast and carries a big range of cruisng essentials and toys-hence the biggish motor.The beam is 8ft 4" and about 7ft at the tuck to give more displacement for the motor et al as well as the normal 4 crew.
However for a 17ft lightweight boat a 2 or 3 hp motor on the stern is a much easier option unless you have strong tidal waters or have more than 4 people onboard.I suggest mounting the ob directly on the stern using a tight fitting ,removable wooden block with rubber mounting-small engines vibrate alot and you dont have much mass to absorb the vibs.6 mm hard rubber is sufficient.Give the rudder plenty of room to swing and use the rudder to stear.If cracks show in the woodwork then you may need to put on some more glass tape and epoxy.
Mike