# Replacing Inboard with Outboard



## Lubrdink (Sep 1, 2011)

You might think I'm nuts but I can't see why it wouldn't work. Maybe I'm missing something. I have a 1970 27' Newport weighing about 6000 lbs with a corresponding 1970 A4 inboard. It starts and runs fine so far but it's getting water into the crankcase and I know there's some serious work ahead, probably a rebuiild. I added electronic ignition this year so it's easier to start but in association with the expected upcoming rebuild and the fact that I have some vibration in the driveline indicating (I think) either bent prop, bent shaft, bearing, etc, I'm wondering if just pulling it and putting on an outboard wouldn't be a better and cheaper answer. We sail on an inland lake and just need propulsion to and from the dock and a little motoring when the wind won't cooperate.

Some pondering on issues:
Positives reasons to change:
1) Easier to pull the motor for repairs
2) Easier to winterize-pull it and take home to the warm garage
3) No propshaft issues (as long as the lower unit is cared for and if there are, see #1)
4) If I use a 4 stroke-use the same fuel tank and simply run the fuel line out the transom
5) If I use an electric start with shifter/throttle controls it would have the same setup as I have now
Possible negatives:
1) Does it change the weight balance of the boat?
2) Is the transom sturdy enough (although this old boat is made like a TANK)
3) Would have to fill in the through hull for the water intake as well as for the propshaft and propshaft mounting bolts).

If this is a foolish idea I know you all will know and know why it is. I appreciate any input from much more experienced boaters than I. Thanks in advance.

PS-I'd take any suggestions on a good long-shaft replacement. The A4 is rated at 30 hp but don't think I'd need that much hp in an outboard. But once again, I defer to the experts.


----------



## Shinook (Jul 13, 2012)

Our boat is also 27ft and displaces close to 8000lbs, she was original designed for an 8hp inboard. The inboard was a block of rust and I didn't want to pay close to 3x what we paid for the boat to put a new inboard in place, so we mounted an outboard off the transom. 

We were told you needed 1 hp per ton of displacement, which would mean we needed at least 4 hp. Rather than "risk" it, we went with the Tohatsu 6 HP Sail Pro, which has an extra long (25in) shaft and a small alternator, we bought it new for roughly $1500. The motor performs wonderfully and pushes our boat at about 5.5-6 knots at 20% power, which is better than the original inboard would do. With current and wind, that obviously changes, but I've never seen it make a major impact. You do NOT need anything over 6 HP, I've seen 15hp outboards on the back of 23ft sailboats before and it is way overkill. With the outboard, you are looking to make and keep momentum, it isn't going to push the boat beyond hull speed. 

The biggest drawback is the prop coming out of the water with any kind of wave action, resulting in a loss of thrust. It has not been an issue for us yet, but it can make getting in and out of places with a lot of big waves complicated. This is the biggest concern, but is manageable if you learn to compensate by sailing the boat. The 25in shaft definitely helps, but it's not perfect. We've pushed against 20 knot headwinds with small swells fine, but you aren't gonna have the same performance you will with an inboard and you can expect to have issues with this at some point.

You will want a good outboard mount with plenty of travel, don't cheap out here, we did and I regret it (we are replacing it next week). I looked around and at the recommendation of James Baldwin of AtomVoyages, we went with the Garhauer OB-125 mount ($250, roughly). The mount is spring loaded to help with weight and has close to 15in of travel. I should be able to comment on it's performance in a week or two, after I pull the old one, fill the holes, and put the new one on.

As for your negatives:

1. We didn't notice any significant balance changes. The motor weighs 75lbs, which should not have a huge impact, but it might. You can always add weight up front to compensate. 

2. Ours is over 1/2'' thick and we reinforced it with a 1in backing plate to be safe. There will be a lot of pressure on the transom at this point, so reinforcing it as much as possible is definitely recommended. 

3. We filled the stern tube with epoxy and glassed over it, if you really want to get fancy, you can build a wood filler for the rudder and keel that removes the empty space where the prop normally sits. We haven't done this yet, but James Baldwin has some info on his site about doing this. We also removed the thru hull and seacock for the motor.

As for using your existing fuel tank, I'm not sure I would do that. If you are going to pull the A4, you might as well remove the risks of having gas in the cabin all together and find a convenient way to mount the fuel tank outside. We removed everything and it opened up a lot of storage space, also removing odors associated with inboards completely.


----------



## Lubrdink (Sep 1, 2011)

Shinook,
Thanks for the EXCELLENT answer. I was hoping someone with experience doing it would reply and your information was just what I was looking for. I thought it could be done but I find a lot of things look good in my head and not always in real life!

I wonder if I might ask: Does your motor have electric start, remote control for throttle and shift? Since my tiller is forward in the cockpit, it's a bit hard to "lean over the transom" to do those functions as some smaller boats can do.

Thanks again for the encouragement and information.


----------



## Shinook (Jul 13, 2012)

No electric start, I don't think that's an option for the Tohatsu models, I could be mistaken, but I know ours doesn't have it. Ours starts pretty easily though, we also pull it out of the water when we are sailing or leaving the boat at the slip, so going back there is required anyway. It isn't that hard to pull up and down if you have the right mount. 

There is a remote control kit, but that would get messy, you have to run a series of cables back to the motor. I took one look at it and said forget it. 

When we use the motor, I rarely do much with the power settings. I usually set it and leave it where it is, then return to the cockpit for however long we plan on motoring. The only exception is docking, when we do that I sit on the aft lazarette lid and can easily reach the controls from there, of both the tiller and motor. 

I won't lie, it's not as convenient as an inboard, but you learn to deal and it's certainly better than what it costs to put an inboard in. I don't regret our decision, I'd do it again.


----------



## Lubrdink (Sep 1, 2011)

Thanks again. Very good info and much appreciated.
Happy sailing! We got a few flurries of snow but supposed to warm up tomorrow and Sunday so, sadly, after that we'll winterize the A4 and call it a season.
Best to you.


----------



## bfloyd4445 (Sep 29, 2013)

Lubrdink said:


> Shinook,
> Thanks for the EXCELLENT answer. I was hoping someone with experience doing it would reply and your information was just what I was looking for. I thought it could be done but I find a lot of things look good in my head and not always in real life!
> 
> I wonder if I might ask: Does your motor have electric start, remote control for throttle and shift? Since my tiller is forward in the cockpit, it's a bit hard to "lean over the transom" to do those functions as some smaller boats can do.
> ...


Modern outboards are very very good.I have a 9.9 merc big foot high thrust electric extra long shaft that has an unbelievable amount of power for a 9.9. It pushes a 40 foot defever trawler just fine so would certainly give you tons of reserve power when needed as well as using very little fuel.

FourStroke 8 - 9.9 HP | Mercury Marine


----------



## Lubrdink (Sep 1, 2011)

Thanks BFloyd. More good info for my decision. I appreciate you taking the time.


----------



## bfloyd4445 (Sep 29, 2013)

Lubrdink said:


> Thanks BFloyd. More good info for my decision. I appreciate you taking the time.


your welcome. As a matter of fact I got the merc by accident. I ordered a custom built boat from Wooldridge boats two years ago and they installed this bigfoot for a kicker. Well the 9.9 isn't needed with my merc 115hp smart craft 4 stroke main engine because the computer controls on the big engine allow me to troll slower and more economically with the 115. So I tried the 9.9 on the trawler to see how it would do cause I had noticed on my Wooldridge how incrediblely powerful the little 9.9 was so thought it would work on the defever. It has the extra long shaft which would make it great for a sailboat and a bigger stronger mount plus electric start and trim. Nice little motor for boats in need of dependable power that sips fuel.
good luck
best wishes
britt


----------



## Loki9 (Jun 15, 2011)

Why not fix your A4? The A4 is simple enough that anyone can do a complete rebuild if needed (and it likely isn't). 

I've had outboards on sailboats and I hate them. They don't perform as well and they look like ass.


----------



## sony2000 (Jan 30, 2013)

You don't need over 10hp, so an electric motor is an alternative. Golf cart technology, and conversions forums are good.
Raise the boats value instead of lowering it.


----------



## benesailor (Dec 27, 2012)

Can't help myself.

I've been thinking i need to install 2 of those AC72 daggerboards on my boat with twin 250hp Mercs. 

Now that would be cool to see!


----------



## Lubrdink (Sep 1, 2011)

benesailor said:


> Can't help myself.
> 
> I've been thinking i need to install 2 of those AC72 daggerboards on my boat with twin 250hp Mercs.
> 
> Now that would be cool to see!


Bene,
That's an option but the Admiral probably wouldn't like me replacing her v-berth with fuel tank!
:laugher


----------



## barefootnavigator (Mar 12, 2012)

My 22' sailboat displaces 7400 lbs, I sail in the San Juan's where we seem to get 30 plus knots more often than not lots of current. I have a 6 hp outboard and love it, if there is wind you can sail and if not I get 4.5 knots at half throttle. For fun and a test I motored into 20 plus knots wind over tide at half throttle and was still getting 2.5 knots it surprised the hell out of me that we could do that. I do have a full keel so cavitation is much less of an issue.


----------



## bfloyd4445 (Sep 29, 2013)

sony2000 said:


> You don't need over 10hp, so an electric motor is an alternative. Golf cart technology, and conversions forums are good.
> Raise the boats value instead of lowering it.


I like the electric idea. Your post made me realize since he already had an inboard it would be easy to go electric drive. Would not be cheap for all the controllers, batteries and electric motor but would most definatly raise the value. Don't laugh electric for a sailing vessel is very doable. Solar panels and the wind can charge your batteries giving you maybe nine hours of run time at 1/2 speed and that's enough for most I would think. West Marine even sells a package to do this. see below: the 2,5 or 3.6kw would work fine on your boat, but $5000

http://www.westmarine.com/webapp/wc...nboard+Propulsion&viewTaskName=SiteSearchView


----------



## sony2000 (Jan 30, 2013)

I'm doing the conversion now with a 7.klw ETEK motor, to drive a Paceship 29.
With 4 batteries I should get 4 hours at near hull speed, and for the cost of a new 9.8hp outboard.


----------



## bfloyd4445 (Sep 29, 2013)

sony2000 said:


> I'm doing the conversion now with a 7.klw ETEK motor, to drive a Paceship 29.
> With 4 batteries I should get 4 hours at near hull speed, and for the cost of a new 9.8hp outboard.


my 9.9 bigfoot was over $3000. That's a good deal I would like to hear details.
I don't have a sailboat but I may be close to owning a westsail 32 which I was thinking of converting


----------



## sony2000 (Jan 30, 2013)

The west coast is strong on conversions, so go to the 
''discussion forum -Electric seas''. for example of boats in the 30 ft. range.
I'm using the basic parts of a motor on a plate with 2 pulleys and a belt, plus the appropriate electrics and electronics. Just keeping it simple.


----------



## bfloyd4445 (Sep 29, 2013)

sony2000 said:


> The west coast is strong on conversions, so go to the
> ''discussion forum -Electric seas''. for example of boats in the 30 ft. range.
> I'm using the basic parts of a motor on a plate with 2 pulleys and a belt, plus the appropriate electrics and electronics. Just keeping it simple.


its not complicated. I will do a parallel hybrid type system until I get the bugs out. After that I don't envision using the disel engine much except for backup


----------



## sailingfool (Apr 17, 2000)

Adding an electric drive with batteries into the already cramped interior of a W32 may mean you can't get into the cabin. 

Sent from my DROID RAZR using Tapatalk 2


----------



## Alex W (Nov 1, 2012)

On a 27' boat I'd normally say that it isn't a good idea. However it sounds like your boat is only sailed on small to medium sized lakes where the waves won't get so large. In that case I think the outboard is a good economical way to go.

One of the best advantages of an outboard is that they come completely out of the water when sailing. This is more efficient than a feathering prop, and the whole motor is the same price as a feathering prop. Make sure that whatever outboard mount you use allows for this easily (it needs to lift up and allow the motor to pivot forward).

The Tohatsu/Nissan 9.8 is available with electric start, alternator, remote controls, extra long shaft (25") and high thrust 4-blade prop. We had one (without remote controls) on our Catalina 25 and it worked nicely. In large and steep waves (much over 3') the prop would occasionally still come out of the water, but it sounds like you won't see those conditions very often. Honestly if you do see them it probably means there is good wind anyway, so you might as well sail.

Downsides are that it is louder, fuel economy is not as good as an inboard diesel, the weight is not as centralized, it looks ugly and can get in the way of a swim ladder, and it hurts resale for anyone who would want to use the boat in coastal waters.


----------



## SHNOOL (Jun 7, 2007)

Alex... thank you! I read through this thread and I've seen some pretty wild advice, which seems common with sailors talking about "kicker power."

I'll try to leave out emotion and talk about practicality.
A) the difference in weight between a 6hp and a wild tricked out 9.9 hp outboard is about 30 lbs (not a lot)
B) A brandy new 9.9 with all the options you want is pretty pricey...$3192 Mercury Outboards 9.9 Horsepower You could do a LOT of rebuild for $3000! And really only a new outboard 4 stroke will give you all you are looking for in it (remote controls, remote electric start, alternator, etc) and have all the parts.
C) The Atomic 4 is a well loved Gasser engine, and generally easy to rebuild. There is LOTS of information available to help you rebuild it yourself, but again for $3+ you could pay someone to do it likely and NOT be over the outboard budget.

You suggestion that hauling the outboard is "easy," would be a pretty large misunderstanding of how hard it is to mount a 9.9 hp motor over the stern of a boat with remote controls, and electric start/alternator... SURE it's easier to REMOVE the outboard than an inboard, but honestly, it's WAY easier to winterize the inboard (pull the water source hose, drop in anti-freeze, crank motor, turn seacock, and close system)... I've done it a thousand times, and I'd prefer that to pulling off the 9.9!

The suggestions that a 4, or 6, or 8 hp motor will push the boat is ALL CORRECT.. but if you aren't racing and weight isn't a consideration, its much easier to find a USED 9.9.

Now I am going to give you the cheapest alternative of all...
Remove the inboard prop... Slap an outboard bracket on the boat, and VERY used (but running) 9.9 without any of the fancy controls (except alternator), and go sailing!

Honestly I think the RIGHT way forward is rebuild the A-4, but only if that is REALLY what is wrong... sounds like the bearing is out, although the water getting in, suggests a gasket is blown too... so you MAY be right.

I'm sorry electric? No... Save that for your solar sailboat projects please. NO I don't want to hear about your torqueedos, or electric sail drives... they all work, but are a silly option for what he's trying to do!


----------



## Shinook (Jul 13, 2012)

FWIW I also evaluated electric and decided against it. It wouldn't cost us much more to put a diesel in and the range was pitiful without carrying 1000lbs in batteries. The folks I talked with about it were really nice, but I just didn't like the system. 

If I was going that route, I'd have put a diesel in.


----------



## fstuart (Oct 3, 2011)

put a 9.9 Tohatsu on a Cal 27 and a friend did it on a Catalina 27 both had electric start and his even had an hydraulic lift. the Cal originally had a diesel inboard the was a rust block.


----------



## misfits (Dec 9, 2011)

There was an article in GOB a couple years ago about a guy in Maine that discarded his diesel & did an electric conversion. He did it with parts otc & I think the cost was around 2K.


----------



## dabnis (Jul 29, 2007)

Some things to consider:

1. The A4 weighs about 350 lbs and is below the water line and near the center of the boat

2. A9.9 HP outboard & bracket may weigh about 150 to 200 lbs , above the water line and way back on the transom

3. Cost for both may be about $3,500 plus possibly having to re- enforce the inside of the transom

4. Having to reach back and down to operate the controls when docking will no doubt be more awkward than your existing controls. 

5. Overall balance of the boat with the outboard will, no doubt, be quite different than the original design. 

6. Should you want to sell the boat, I think it would be more valuable with a properly running A4 in it than with an outboard. 

We had a Coronado 25 on San Francisco Bay which can be very rough & choppy. It had a pretty good well arrangement but it was somewhat awkward to reach down & in the well to shift when docking. It was not unusual to see boats with transom mounted outboards having their props coming out of the water when it was choppy.

For about $3,500 you could probably have a lot of work done on your A4.

Paul T


----------



## bfloyd4445 (Sep 29, 2013)

sailingfool said:


> Adding an electric drive with batteries into the already cramped interior of a W32 may mean you can't get into the cabin.
> 
> Sent from my DROID RAZR using Tapatalk 2


There seems to be lots of room in the engine compartment for batteries. Granted it will take some engineering to make mounts for the bats. However, I'm not sure more weight that far aft is such a good idea and have been thinking of using the area under the cabin floor were the water tanks are. Don't need 80 gallons of water with a water maker.


----------



## Shinook (Jul 13, 2012)

dabnis said:


> 2. A9.9 HP outboard & bracket may weigh about 150 to 200 lbs , above the water line and way back on the transom
> 
> 3. Cost for both may be about $3,500 plus possibly having to re- enforce the inside of the transom


There is no reason to get a 9.9 on this size boat, 6 HP will do really well and only weighs 75lbs. We paid $1500 for ours, reinforcing the transom cost less than $20, and the mount $250 ($400 if you count the first mount we bought that was a POS).

Not even close to $3500.


----------



## bfloyd4445 (Sep 29, 2013)

Shinook said:


> There is no reason to get a 9.9 on this size boat, 6 HP will do really well and only weighs 75lbs. We paid $1500 for ours, reinforcing the transom cost less than $20, and the mount $250 ($400 if you count the first mount we bought that was a POS).
> 
> Not even close to $3500.


my 9.9 4stroke merc bigfoot weighs 96 pounds including mount. Also made in the 8hp size. Mine is the top of the line power tilt electric start model and it was around $3,000. Remove some of the feature and the price drops dramatically.


----------



## dabnis (Jul 29, 2007)

Shinook said:


> There is no reason to get a 9.9 on this size boat, 6 HP will do really well and only weighs 75lbs. We paid $1500 for ours, reinforcing the transom cost less than $20, and the mount $250 ($400 if you count the first mount we bought that was a POS).
> 
> Not even close to $3500.


Can only speak from my own experience. I had a Coronado 25, about 4,500lbs, IIRC. Started out with a 6 HP 2 stroke which was Ok in calm flat conditions. As we used to make long runs to the outside ocean for salmon fishing, time was important. Replaced it with a 15 HP 2 stroke, which was the same size and weight as a 9.9 HP. It would punch through anything at hull speed. A 9.9 HP would have probably been enough.

In any event, as you mentioned, Outboard costs can vary. We just bought a new Tohatsu 6 HP 4 stroke for about $1,600. I guess my point is, regardless of cost comparisons, my choice, having owned both inboard & outboard boats, would be to try to repair the A4 and keep the boat in it's original design configuration.

Paul T


----------



## sony2000 (Jan 30, 2013)

Its not all about the cost putting on an outboard instead of an electric motor. Outboards are not that pleasing to the eye on the back of a sailboat.
Being in my 60s, I'll be able to easily remove any or all of the system by myself. My usual sailing will take 25% of the full speed power, and I have 110 volts waiting for me back at the slip. There will be 4 batteries Walmart sized, onboard. If I want to sail salt water, the boat goes on the trailer and a Cummings diesel will take me there in two days at 60 mph not 6 mph.


----------

