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Bull City

Outboard motor in well - Folding prop?

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I'm looking at a boat that has an outboard well. I wonder how badly it will affect performance. The boat is long and slender, low freeboard, not much windage, about 5000 lbs. displacement.



I suspect the lower unit and prop will create a lot of drag. Would a folding prop make much difference? Is there such a thing for outboard motors? Would a two bladed prop make a difference?



Without a fairing plug, will the aperture create a lot of turbulence? How do you make a fairing plug?



The boat comes with a 6 HP 4-stroke. It seems like a lot of engine for this boat on the lake where I sail. I could sell it and go with a Torqueedo. The Travel 503/1003 is rated for day sailers up to 3,000 lbs., but I think it could handle this boat on our lake. The boat has a solar panel on the lazarette which could help power it.



I have a Honda 2 HP long shaft that is more than adequate for my J22. It would probably push this boat OK, but not create as much drag.



Any ideas or suggestions?


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A 6hp outboard for a 5000 lb boat is about right if you want to go upwind in anything above 8 kts wind. My Torqueedo 1003 is fine for in/out of the marina in my 2400 lb boat but upwind against 16kt winds I get 2kts for about 30min before the battery gives out. Even a large solar panel will not power the Torquedo enough to run on solar. The propeler cannot cause any drag if it's not in the water when under sail.

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I'm looking at a boat that has an outboard well. I wonder how badly it will affect performance. The boat is long and slender, low freeboard, not much windage, about 5000 lbs. displacement.

 

I suspect the lower unit and prop will create a lot of drag. Would a folding prop make much difference? Is there such a thing for outboard motors? Would a two bladed prop make a difference?

 

Without a fairing plug, will the aperture create a lot of turbulence? How do you make a fairing plug?

 

The boat comes with a 6 HP 4-stroke. It seems like a lot of engine for this boat on the lake where I sail. I could sell it and go with a Torqueedo. The Travel 503/1003 is rated for day sailers up to 3,000 lbs., but I think it could handle this boat on our lake. The boat has a solar panel on the lazarette which could help power it.

 

I have a Honda 2 HP long shaft that is more than adequate for my J22. It would probably push this boat OK, but not create as much drag.

 

Any ideas or suggestions?

All well setups I've seen allow the prop to retract out of the water and have some sort of bomb bay door arrangement to seal the aperture, otherwise there's not much point. With the prop up and door closed, the drag should be much less than normal prop setups. With no door though it would likely be considerably worse.

 

Mine was on a pivoting bracket. The bomb bay door was fabbed from GRP to the size of the aperture. A lip should be molded around the top of the door to make it impossible for the door to invert (ask me how I know this) .One side was attached to the hull bottom with hinges. On the other side was a catch to lock it in place. A line can be attached to lift the door. You can do it by hand, but may require some gymnastics.

 

a 6 HP 4 stroke should be fine, but at 5000 lbs, probably nearing the limit unless you are always powering in flat water and little wind. Torqueedo is OK, but limited range - maybe an hour at hull speed. Range increases a fair amount if you were to accept motoring at 2 knots. They consume a lot of juice. The solar panel may help recharging at the dock, but will do little to increase range.

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I've seen them retract, but not have any door type arrangement. What are you looking at now Bull? Except for the 5000 lb bit I was thinking thhat it might have been a Niagara 26. Will the present owner let you go out on a test sail/motor with your Honda 2?

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It's a Columbia Sabre, on the hard. A test sail is not on, since it would require transport to a yard, rigging, and splashing and then the reverse.

 

The aperture of the well is all below the waterline, and will not allow the motor to tilt. One concern with my Honda 2 HP is prop spin. The motor has a forward gear and a centrifugal clutch. I don't think the shaft can be locked, so I would have constant prop spin.

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Ideas:

 

Bottom of the aperture:

Make 2 rectangular rubber flaps, that together will cover the aperture. Attach them to the outboard edges of the aperture so that they meet at the centerline. While not watertight, this might stop most sloshing and turbulence inside the well. Cut out the inside edges of the flaps to fit snugly around the outboard motor lower unit.

 

Lower unit:

Remove extraneous fins and appendages. Maybe add a folding prop, except they seem to cost more than the outboard.

 

Thoughts??

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A folding prop for an outboard motor? Never seen one in my life,

I read about one on another forum, an unspecified Flex-o-fold on an unspecified Yamaha outboard, I do not have the details yet. Unfortunately, a Flex-o-fold costs almost as much as or more than the outboard.

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Having the opening well below the WL may create issues with seawater flooding the outboard. A Dash 34 in Seattle installed a Melges 32 style system (I believe they use a SOCA system, similar or the same as Hendo 30) and went through 2 outboards in 2 years and said it was a mistake. I was thinking the Columbia might have the same setup as the old Thunderbirds and HF 27 that had the opening slightly above the DWL and even then probably 6-8" of water filled the well under power.

 

Why not just attach a long leg O/B to the transom?

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A folding prop for an outboard motor? Never seen one in my life,

I read about one on another forum, an unspecified Flex-o-fold on an unspecified Yamaha outboard, I do not have the details yet. Unfortunately, a Flex-o-fold costs almost as much as or more than the outboard.

 

Flexofold makes a 12x7 prop for the Saildrive 330, which is a Parsun 4-stroke OB with a motor mount and glass base built around it. Clever and light, but not cheap. But what is? They will also sell you just the prop for US$1400

 

http://www.saildrive.se/eng/eng_index.htm

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Frankly, on a boat like that the prop is probably the least of your worries..... Go with a 2 stroke or smaller 4 and put it below if racing. Glass over the hole and stick a bracket on the transom if you are that worried about it.....

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Hanging an O/B from the transom won't work well because the boat has long lazerette deck. It would be a very long reach to the controls from the cockpit. I don't like the idea of removing a gasoline motor while underway and stowing it below.

 

The best option may be a Torqueedo 503/1003 mounted in the well. It could removed and stowed more easily than a gas O/B (lighter, no fuel spills).

 

The only problem then is the open aperture.

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Hanging an O/B from the transom won't work well because the boat has long lazerette deck. It would be a very long reach to the controls from the cockpit. I don't like the idea of removing a gasoline motor while underway and stowing it below.

 

The best option may be a Torqueedo 503/1003 mounted in the well. It could removed and stowed more easily than a gas O/B (lighter, no fuel spills).

 

The only problem then is the open aperture.

 

Put on a throttle and electric start. You'll be happy you did. I cannot reach my outboard from my tiller, and am VERY happy I have both. Simply tilt the motor back into the drink, back to the tiller and fire her up. An added bonus with the electric start is many outboards will also have an alternator. Juice up the battery while putting out/in. Do a little research and you'll be pleased with this type of set up.

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look at this film:

 

 

At 40 sec a nice outboord folding systhem is shown. Has bom doors to close the gap in the bottom

That is very sexy. I cannot imagine how much it would cost.

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You looking at the one in RI? Looks pretty cherry, although overpriced ...probably because he had done so much restoration. Since the well is in the cockpit, taking it out of the well would be very easy, short trip down into the cabin. But, with all the wetted surface on the huge keel, leaving it in and in gear to stop prop rotation, is probably not bad. If you buy it, just be empirical - try it out, in and in gear, etc. - and record the speed. The well is well aft and I bet when she's healed over the open well is not even in the water; she heels a lot since there is no form stability - heeling lengthens water line and you take off.

Cheers, Greg

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It's a Columbia Sabre, on the hard. A test sail is not on, since it would require transport to a yard, rigging, and splashing and then the reverse.

 

The aperture of the well is all below the waterline, and will not allow the motor to tilt. One concern with my Honda 2 HP is prop spin. The motor has a forward gear and a centrifugal clutch. I don't think the shaft can be locked, so I would have constant prop spin.

 

Doesn't the motor lift on tracks or something? I've never seen a bay mounted motor that did not. Look closely.

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The problem with leaving the motor down is two fold. One, it will suck a TON of speed. More importantly, any outboard I've ever met can't be left in the water for long periods or the whole lower unit will very quickly corrode and disappear. Well systems are all well and good, but you need to be able to retract the motor and ideally get the motor dry.

 

Sabre is similar in proportions to a Dragon or Etchells, I have seen both of those models use a stern-hung outboard, which is inconvenient at the dock or in waves, and I have also seen both use a clamp-on aluminum bracket over the side of the boat, adjacent the helm. For a small 5hp or less motor, this seems to work reasonably well. Obviously you still need to muscle the thing into the boat before sailing.

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More importantly, any outboard I've ever met can't be left in the water for long periods or the whole lower unit will very quickly corrode and disappear.

 

Further to that point, I've seen instances where the water intake became clogged with growth, so the engine ended up overheating

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I appreciate all of these comments.

 

I think the outboard well is a liability for the following reasons: (1) the lower unit and propellor cause drag (2) the well invites turbulence, becoming a washing machine which has got to be bad for boat speed (3) it's not good to have the outboard submerged for extended periods (4) so, if you have to mount the goddamn outboard when you get to the boat and leave the marina, stow it when you sail, re-mount it when you re-enter the marina, and then stow it when you secure the boat and go home, well I say fuck it, and furthermore, (5) why would you buy a boat that has a well that causes so much extra work and then have to build or buy a plug to make believe it isn't there.

 

Thank you all.

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With auxiliary engines, you have to pick your poison.

 

Inboard diesels are convenient, but pricey and expensive to replace, consume interior space and a bit draggy

Outboards on the transom are inexpensive and no drag, but impact the aesthetics and have operating issues related to getting it in and out of the water and starting the thing

Outboards in a well are inexpensive, have low drag if sealed off, and don't impact the aesthetics. However, they consume space, create issues of retracting and lowering the engine and starting, potential for engine to drown.

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