Outboard on a Catalina 27

[sanibel sailor]

Originally Posted by new-to-sailing

Interesting thread, didn't see any commentary on the Shaft Length assuming most had 15". I supposed I could experiment with raising the transom etc later down the line or modifying the shaft length?

Modifying the shaft length require not just a new midsection, but lower unit as the driveshaft is too long. Shift rod likely needs some attention as well. Might get lucky with a parts motor that has a bad powerhead.

[Adelie]

Originally Posted by new-to-sailing

Interesting thread, didn't see any commentary on the Shaft Length assuming most had 15". I supposed I could experiment with raising the transom etc later down the line or modifying the shaft length?

Modifying shaft length would require a new lower unit. Probably not worth the cost and hassle but never know.

Raising the transom height on the stern would be the way I would do it.
Before that I would look into a tiller extension and a long fuel hose so weight could be shifted as far forward as possible when trying to get on a plane.

If you want a motor that is going to work OK for both dinghy & mothership you are going to need to compromise.
High-thrust is preferred for both so there's no compromise there and you get a small electrical source to boot.
Compromise is going to be shaft length. Longer shaft is better for mothership, shorter is better for dinghy unless you raise the transom, and even then you are going to have to pick between long and extra-long.
Getting 6hp instead of 5hp means that you are more likely to get on a plane despite the extra shaft length. Depends on the dinghy you have too.

If you don't need to get on a plane, then it doesn't matter if you get the extra-long shaft or whether it's 5hp or 6hp.

[Adelie]

Originally Posted by new-to-sailing

Appreciate the replies! Great to see an example of someone powering a similar sized boat.

I am going to go with the long shaft (20") as in the short term powering the sailboat is more of a priority. I shouldn't have any issues mounting it fairly close to the water getting a lot of the shaft submerged so don't see a ton of upside for the 25" especially if I consider future dinghy use. I will also get one of the sailpro models.

I am still torn between the Propane and gas, if I am not worried about availability of the propane are there any other downsides? I like the idea of using propane for storage, fuel quality, and simplicity. I've also read that the carburetor on a gas engine can have issues if not run frequently (I have no experience with gas engines) so keeping the system simple and lower maintenance certainly a plus for me.

Fuel issues for motors not run for long periods are in large part but not completely related to the ethanol in the fuel. Ethanol absorbs water which clogs the jets with gummy deposits.

The 2 solutions are to not get fuel with ethanol in it or remove it from the fuel you buy.

My brother in law in MN has one service station he knows of in his small city that has non-ethanol fuel at a slight cost premium. There is no ethanol free fuel in California that I have been able to find.

To remove ethanol....... add water.... and dark food coloring. Ethanol is hydrophilic and would rather mix with water than gasoline. Add about 1/2gal water to 5gal fuel in a clear jug with a tap at the bottom. Shake it up and wait 15min. The water ethanol mixture will be colored making it easier to discern water from fuel when discharging the mixture. You should get about 1gal of water/ethanol mixture leaving you with about 4.5gal gasoline.

Ethanol is an octane booster, about 2pt or so. So either start with a premium fuel or use an octane booster after removing the ethanol. Some octane boosters are ethanol so be careful about which one you buy.

[thomm225]

Originally Posted by new-to-sailing

Appreciate the replies! Great to see an example of someone powering a similar sized boat.

I am going to go with the long shaft (20") as in the short term powering the sailboat is more of a priority. I shouldn't have any issues mounting it fairly close to the water getting a lot of the shaft submerged so don't see a ton of upside for the 25" especially if I consider future dinghy use. I will also get one of the sailpro models.

I am still torn between the Propane and gas, if I am not worried about availability of the propane are there any other downsides? I like the idea of using propane for storage, fuel quality, and simplicity. I've also read that the carburetor on a gas engine can have issues if not run frequently (I have no experience with gas engines) so keeping the system simple and lower maintenance certainly a plus for me.

So I had to get around some tankers here and if I didn't have a 25" shaft outboard, it would have been coming out of the water.

Once around I went back to motorsailing. (as in sail assisting the motor)

I still had 20 miles to go and wanted to get back before like 2-3 pm

Notice the main is reefed.

With the outboard just above idle, you can point a lot closer to the wind.

https://www.youtube.com/watch?v=ri0c5GnZ1I8

[SV_FlyingTigress]

See the watermark on the long shaft Tohatsu 9.9 in the picture of my catalina 27 for required shaft size

[MartinF]

Why is this temporary? If it is because you have a non-working inboard engine the best solution is to fix the engine now. If you put a short-shaft engine sufficiently low on your stern you will have problems accessing the engine controls, and the engine is likely to get wet when you are heeled in a chop. The dinghy is another question. If you aim to carry the dinghy you will only have space for the smallest possible soft dinghy. Planing is irrelevant. Lifting a 60lb engine over the rail will be impractical/impossible. Get a 2 or 3hp motor or a 6' pair of oars. Towing a dinghy is an alternative. You could tow a solid boat which would be easier to row/paddle.
Good Luck,
M

[Adelie]

I got impression it was temporary because he intends to buy a bigger boat.

Most Cat-27s are outboard driven, the have a lazarrette at the back of the cockpit for a motor well. You can see this in the photo 2 posts back. Consequently remote controls are not needed.

Lifting a motor back and forth between motorwell and dinghy can be accomplished with a block and tackle at the end of the boom.

Roll up floor and air flor inflatables would be the most common options on a Cat-27.
Given how narrow and useless the side decks are a folding boat would actually be a pretty good option.
I prefer a solid dinghy that can be brought aboard so a nesting dinghy is a possibility. 9’ 2-paw by B&B might fit somewhere.

[new-to-sailing]

The reason for adding the outboard is that I am having trouble with the inboard, so it will be mounted with an adjustable bracket. I will likely get the inboard up and running within the next month or so but more than anything just like the idea of having a backup option for peace of mind. I know that many will say it's a waste but that's OK! I know I will need a dinghy motor at some point so this is a perfect solution for me.

Reasoning aside and back to the shaft length question, how deep in the water should the propeller be ideally, I'm sure the more the better but anyone have a safe amount? My transom is 36" tall, I have easy access to attach the bracket so the bottom of it would be about 10" above the waterline. That puts the top of my bracket about 18" above the waterline I believe (using a Panther 55-0407AL), would a 25" shaft be needed in this case, want to go with the 20" shaft if possible.

[new-to-sailing]

Originally Posted by Adelie

Fuel issues for motors not run for long periods are in large part but not completely related to the ethanol in the fuel. Ethanol absorbs water which clogs the jets with gummy deposits.

The 2 solutions are to not get fuel with ethanol in it or remove it from the fuel you buy.

My brother in law in MN has one service station he knows of in his small city that has non-ethanol fuel at a slight cost premium. There is no ethanol free fuel in California that I have been able to find.

To remove ethanol....... add water.... and dark food coloring. Ethanol is hydrophilic and would rather mix with water than gasoline. Add about 1/2gal water to 5gal fuel in a clear jug with a tap at the bottom. Shake it up and wait 15min. The water ethanol mixture will be colored making it easier to discern water from fuel when discharging the mixture. You should get about 1gal of water/ethanol mixture leaving you with about 4.5gal gasoline.

Ethanol is an octane booster, about 2pt or so. So either start with a premium fuel or use an octane booster after removing the ethanol. Some octane boosters are ethanol so be careful about which one you buy.

When removing the ethanol after mixing it up are you then just able to hand pump out the ethanol, assuming it's pretty easy to see and groups together?

[Adelie]

The easiest way to remove the water ethanol mixture is with a clear container that has a tap at the bottom. Something like this:

https://www.amazon.com/dp/B0735YMHS3...v_ov_lig_dp_it

The water ethanol mixture is denser than gas so it sinks to the bottom. Food coloring helps discern what’s the mixture and what’s fuel. Fuel won’t hold the color in suspension like water.

[Lee Jerry]

Originally Posted by new-to-sailing

Hello everyone, I am planning to add an outboard to my Catalina 27, it will likely be a short term situation (1-2 years) so thinking about how I could reuse the outboard I buy for a dinghy down the line. A few questions related to my plan below.

1. I am planning to buy a 5hp Tohatsu Propane, I believe this should give me the power I need. I will only need this for getting in and out of my slip and the occasional longer trip which would only be in calm conditions. I have seen some who say this is fine, others suggest going for more HP, anyone have thoughts on this? Or better yet is there any sort of calculation that can be done given hull etc. to see how this will fare.

2. Most people use a 20” or longer shaft it appears for this type of application, if I install a bracket that allows the prop on a 15” to be installed as intended is there any other reason I should use a long shaft? A big reason I want to use the 15” shaft is to make this outboard more usable for a dinghy down the line.

3. Any recommendations for outboard dealers in the Chicago area? Or recommendations for adjustable outboard brackets?

I know there is a lot on here and certainly a well discussed topic but any thoughts or other resources on this would be great! Happy to clarify if needed.

It is unlikely you would be able to use the same outboard for both the sailboat and the dinghy. If you try, one or more likely both, will give you sub-standard performance. Repeating somewhat from said above...

I think 5hp is too small for the boat. Yeah, it may work getting in/out of the marina and maybe even give acceptable performance in calm water, not sure you'll quite get to hull speed (probably close enough, though). But you will eventually find yourself in other than calm water and grossly underpowered.

The sailboat needs a long (or extra long) shaft. Without it, depending on height of mounting (when lowered for operation), you'll have some combination of inadequate prop submergence (even in calm water), inability to reach the motor controls (particularly around the dock), and prop ventilation in any kind of waves (including power boat chop). A long shaft on the dinghy will only result in extra drag, resulting in lower speed (probably preventing planing), higher fuel consumption, increased draft (in / around shallow waters) and additional weight with no benefit.

My recommendation would be to fix the existing diesel. Failing that, get a "proper" outboard for the sailboat (long shaft, 8hp minimum or 9.9hp better) and then when the time comes the proper outboard for whatever dinghy you get. Sell the first one if desired to recoup some funds.


Oh, and the "high-thrust" label on these small engines is probably just a different propeller that comes with the engine (i.e. one diameter size up and one pitch down); there probably isn't even a different gear ratio (but if there was, then it might mean something).

[OldManMirage]

If it's really that temporary - a month - you want the short shaft. If you get a long shaft you will end up selling it. A long shaft outboard just doesn't work well on dinghys.

[thomm225]

Originally Posted by new-to-sailing

When removing the ethanol after mixing it up are you then just able to hand pump out the ethanol, assuming it's pretty easy to see and groups together?

You don't need to worry about the ethanol. The new engines are built for it.

Just use Sta-Bil in your gas if you don't plan to use it all in a month or two.

[thomm225]

Originally Posted by Lee Jerry

It is unlikely you would be able to use the same outboard for both the sailboat and the dinghy. If you try, one or more likely both, will give you sub-standard performance. Repeating somewhat from said above...

I think 5hp is too small for the boat. Yeah, it may work getting in/out of the marina and maybe even give acceptable performance in calm water, not sure you'll quite get to hull speed (probably close enough, though). But you will eventually find yourself in other than calm water and grossly underpowered.

The sailboat needs a long (or extra long) shaft. Without it, depending on height of mounting (when lowered for operation), you'll have some combination of inadequate prop submergence (even in calm water), inability to reach the motor controls (particularly around the dock), and prop ventilation in any kind of waves (including power boat chop). A long shaft on the dinghy will only result in extra drag, resulting in lower speed (probably preventing planing), higher fuel consumption, increased draft (in / around shallow waters) and additional weight with no benefit.

My recommendation would be to fix the existing diesel. Failing that, get a "proper" outboard for the sailboat (long shaft, 8hp minimum or 9.9hp better) and then when the time comes the proper outboard for whatever dinghy you get. Sell the first one if desired to recoup some funds.


Oh, and the "high-thrust" label on these small engines is probably just a different propeller that comes with the engine (i.e. one diameter size up and one pitch down); there probably isn't even a different gear ratio (but if there was, then it might mean something).

A 5 HP outboard is fine unless you are more of a power boat guy than a sailor.

I have used one for 12 years now on basically the same size boat

I would go with the 25" shaft though. If you are having problems with the inboard now you will probably continue to have problems with it because I'm sure it's old right?

When I removed the diesel and associated equipment from my boat, it was 400 lbs. lighter and I gained storage space.

I removed the 352 lb. Bukh 10 HP diesel, motor mounts, prop, prop shaft, metal 20 gallon fuel tank, copper fuel lines, flange, stuffing box, excess wiring, and lots of oil, grease and sludge from 37 years of the engine being in that spot

[SV_FlyingTigress]

Originally Posted by OldManMirage

If it's really that temporary - a month - you want the short shaft. If you get a long shaft you will end up selling it. A long shaft outboard just doesn't work well on dinghys.

I agree on the above with the caveats states, again, look at how much shaft is below the waterline in my C27 picture above.... my motor is a Mercedes 9.9, sorry not a tohatsu.... but I suspect you could get away with a short/medium shaft just fine if not operating in rough/high-current coastal waters.