Wondering about a F25 outboard to inboard conversion

Engines, Drive trains, Propellers, Steering, Ground Tackle and other mechanical system
johncd3141
Posts: 13
Joined: Thu Feb 12, 2009 5:56 pm

Wondering about a F25 outboard to inboard conversion

Post by johncd3141 »

I have a Freedom 25 with an outboard and am starting to think about refitting a diesel inboard.

Has anyone already done this? Any suggestions as to the best way to proceed.

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moosemcclintock
Posts: 81
Joined: Tue Jun 28, 2011 8:09 am

Re: Wondering about a F25 outboard to inboard conversion

Post by moosemcclintock »

I don't know how to do it but if I had an outboard, I'd stay that way. I don't believe the F25 was designed with an inboard in mind. My F25 sits way stern down, all the time, the engine weight plus the gas tank are more than the back of the boat will support. This is most noticeable in the waterline, the etched hull line is underwater all the time, as is the waterline on the rudder, and the bow is really far up and out of the water. I've moved everything else forward but it still sits stern down, this is really noticeable in light air sailing, the whole back of the boat drags and makes a lot of turbulence. Just my thoughts.

unfetteredalexandria
Posts: 128
Joined: Sun Feb 22, 2009 1:57 pm

Re: Wondering about a F25 outboard to inboard conversion

Post by unfetteredalexandria »

I thought about doing this a few years ago seriously enough to get a couple quotes. We considered both adding a saildrive and doing a regular shaft. The saildrive is probably the easier install, but they are very expensive. The cheapest option was to get a small non-marine diesel, like a kubota, and adapt it. Rather than installing a rigid tank, we considered a fuel bladder in the underseat locker aft of the holding tank.

In the end, I'm glad I did not do it. Anything you can do to get weight out of the back will make things better. For the money it will cost, you could get a Torqeedo outboard and a Torqeedo lithium battery, and probably still save. The total weight is the not too different from a gas outboard, but you can put the battery up near the keel, under the sink, and get a nicer weight distribution. The electric outboard is light enough you can easily just lift it off the mount and store it below. But the simplest thing is just to stick with the lightest outboard you can get away with.

In my experience, 10hp is way more than needed except in big wind and waves, and honestly, in those conditions, the boat is nicer to handle with the main double reefed than trying to go bare poles, and having the prop pitching in and out of the water and overspeeding each time it starts to cavitate. Sure you can push the boat to well above hull speed with a 10hp outboard in calm conditions, but it's a sail boat after all.
1984 round-mast Freedom 25
Western Shore of the Chesapeake

yarrow
Posts: 210
Joined: Fri May 14, 2010 6:38 pm
Location: providence RI

Re: Wondering about a F25 outboard to inboard conversion

Post by yarrow »

My inboard F25 sits with the stern out of water, barely but it is out. from looking at posts I feel a big part of this is the large over weigh ruddgers often get water logged and pull stern down.
cheers,
Yarrow
82' F25 winged spar, inboard diesel
95' B3 I-14
providence RI

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hxschiller
Posts: 88
Joined: Sun Dec 07, 2008 7:55 pm
Location: Mull 28 - "Impulse" on NW Creek in New Bern, NC

Re: Wondering about a F25 outboard to inboard conversion

Post by hxschiller »

Forget the discussion about horsepower; THRUST is what you need. The F25 needs about 6 HP with an appropriate propeller (which never come standard with the usual outboard motor). Look to the aftermarket prop manufacturers such as "Michigan Wheel" for a large-bladed low pitch prop that is generally intended for "workboat" use. Unfortunately, all the appropriate sized (and weight) outboards are marketed to the fishing (aluminum) runabout world, and you can't seem to find a small (4 - 6 HP) outboard engine with a "thrusty" prop available as an ordering option.

unfetteredalexandria
Posts: 128
Joined: Sun Feb 22, 2009 1:57 pm

Re: Wondering about a F25 outboard to inboard conversion

Post by unfetteredalexandria »

Could not agree more. I got OK results by going down to 5" pitch, but larger diameter would be even better. Even still, the 10hp motor is usually overkill.
1984 round-mast Freedom 25
Western Shore of the Chesapeake

Tricia
Posts: 107
Joined: Fri Dec 05, 2008 9:59 pm

Re: Wondering about a F25 outboard to inboard conversion

Post by Tricia »

I had a Yamaha 8hp 2 stroke and put a Yamaha high thrust prop on it. Worked great.

bjohnson66
Posts: 18
Joined: Sat May 26, 2012 8:01 pm

Re: Wondering about a F25 outboard to inboard conversion

Post by bjohnson66 »

I'll confirm what the other owners of Freedom 25 inboards have said. The inboard adds too much weight to the stern. I am thinking about converting my diesel to electric to try and solve the problem. If mine was an outboard I would leave it that way.

The only two things I can think to do to try and get better weight distribution is to fix the fuel gauge so I do not have to keep the tank as full as I do and to move the batteries to the bow. If anyone has any other ideas I would like to hear them.

Goose13
Posts: 77
Joined: Tue Aug 19, 2014 7:18 pm

Re: Wondering about a F25 outboard to inboard conversion

Post by Goose13 »

I'm in the process of going electric (the final stage). I'm going to put it all on this site once I have all of the data. Its been a great experiment and I THINK I made the right decision. I'm on a F33 CK so the data will be a little different, if you have any questions let me know.
Doug and Marie
Millennnium Falcon F33 CK cb #4
1980 wish bone booms Electric Drive

midnightsailor
Posts: 140
Joined: Thu Aug 06, 2009 1:21 pm
Location: Greenport, New York

Re: Wondering about a F25 outboard to inboard conversion

Post by midnightsailor »

love go hear about you experience with electric conversion. I also have F33 so data would be directly applicable. For now my 3gm is in very good condition but if it ever needs replacing I would certainly consider going electric.
1982 Freedom 33 Cat Ketch, Hull # 53, Standard Booms, deep keel ,tall rig
An armed man is a citizen, An unarmed man is a subject. George Washington

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