Can I move my 38-foot boat with an outboard?

[piloto]

Originally Posted by Bluenoserumlvr

I have a troubled diesel on my Sabre 38, which covid has kept from me for too long. I will shortly be reunited with it, and want to head south from Florida. It sails well and I only plan to use a motor for marinas. Here's my question: What is stopping me from using an outboard just to move around marinas? I have a 6hp. How fast would that move a 15,600-pound boat. How do you rig an outboard on a big sailboat like that? Am I totally mad to even think about this?

Bluenose, I have the same view as Boaty, and sailed SF to and through the Panama Canal and into San Blas with a 6hp Johnson OB on a tilt mount off the stern of my 29’ Cascade. My IB engine was a highly suspect Atomic 4 gas bomb that, when removed and gifted to the locals in San Carlos, Mexico provided room for sails and gear and no more built in Molotov cocktail while enroute or stationary.

[Bill_Giles]

The most effective way of using an O/B to move a bigger boat is to strap the tender alongside.

[CyKlop]

One thing I haven't seen discussed is maneuverability in the marina using the outboard.


Will he have enough water over the rudder to actually steer and maneuver?


At very low speeds, like for docking and pulling into a slip, I rely on prop wash/walk for maneuvering. While he MIGHT get some prop walk out of that small an outboard on the boat, he won't get any wash at all.


Combine that with the very slow acceleration (to get up to a maneuvering speed where he'll have some rudder authority) and he could easily get into some trouble in tight quarters in my opinion.

[lestersails]

Originally Posted by YellowBoat

Just did a bit calculation over the thumb . Your 15600 pound boat will be able to reach about 3.5 knots in flat water and no headwind . Only it will take several minutes to actually reach that speed. Questions like these calso can be calculated quite accurate ( and betetr than my thumb) with : https://vicprop.com/displacement_size_new.php . You just need a it more data for your boat .

Probably obvious but the caveats of flat water and no headwind would get you to SOW. If you want it to be SOG then you should also specify no current as well?

[boatman61]

Originally Posted by CyKlop

One thing I haven't seen discussed is maneuverability in the marina using the outboard.


Will he have enough water over the rudder to actually steer and maneuver?


At very low speeds, like for docking and pulling into a slip, I rely on prop wash/walk for maneuvering. While he MIGHT get some prop walk out of that small an outboard on the boat, he won't get any wash at all.


Combine that with the very slow acceleration (to get up to a maneuvering speed where he'll have some rudder authority) and he could easily get into some trouble in tight quarters in my opinion.

Practice makes perfect..

[MicHughV]

Some many years ago I was in a fishing competition.

In order for the fish to be weighed, you had to bring it to the weigh-in dock without outside assistance.

One hapless boater ran out of gas about 2-300' from the dock. Probably a 24 footer or thereabouts, give or take 3-4,000 lbs.

Undeterred, he jumped over the side, stock the bow line in his mouth and pulled the boat up to the weigh in dock, much to amusement of the watching crowd.

Don't recall if his fish won a prize though, but was mightily impressed with his feat.

A swimmer with a rope in the mouth must equate to 0.05 hp maybe...

[trilleen]

Originally Posted by Bluenoserumlvr

I have a troubled diesel on my Sabre 38, which covid has kept from me for too long. I will shortly be reunited with it, and want to head south from Florida. It sails well and I only plan to use a motor for marinas. Here's my question: What is stopping me from using an outboard just to move around marinas? I have a 6hp. How fast would that move a 15,600-pound boat. How do you rig an outboard on a big sailboat like that? Am I totally mad to even think about this?

As others have said a far better option for safety and security and probably keeping your insurance happy should a claim be made would be to sort your inboard diesel. "troubled you say" what does that mean ? Sure you can sail without an engine but there will be times when a decent inboard can get you out of trouble or even just be more convenient rather than having to stay out at sea while waiting for conditions to improve or strong tides are running. A cautionary tale but a friend crossing Biscay in rough conditions found that his stern mounted outboard had broken free and had deep sixed itself on passage he had his hands full anyway and did not notice until he needed to use it to enter port he called up harbour control for a tow in

[Nibiruwayne]

To the original question: From my experience, I have to agree with those on this thread who advise you fix your inboard engine which will also involve going through your fuel lines and filters. To manage a big boat, I consider 38' a big boat, you will have a keel that requires some time, power, and speed to maneuver around and avoid obstacles, many of them moving. Your liability with a 6 hp. outboard, simply isn't practical or safe for you, your crew, or others out there. As one post pointed out, your insurance would likely be void if you had an accident, and God forbid someone was hurt.
I would use it as an emergency backup only.
All the best

[JimmyDarci]

46 foot cat used to have two 9.9 Yamaha high thrust engines. We upgraded to Yamaha T25Xwtc and get up to 9 knots easy cruising. Just get one of those on a center engine mount and you can go upswing or in chop too. The key is extra long shaft 25” (less cavitation) and higher thrust with special prop for extra thrust. Great engines - highly recommend and so much cheaper than a diesel. Hard to come by during pandemic. Also efficient fuel and one would move your 37-38 foot boat at about 5 knots no issues. For best results use a Seafoam or Yamaha equivalent for lower rpm or longer duration running. OBs have issues with ethanol gas and these products help a lot. Also change spark plugs more frequently as plugs need higher RPMs to keep clean. Otherwise a dream to have decent power from an outboard(s). Would rig this way again every time.

[merrydolphin]

I have moved my 44’ a few times hip towing with a 15 2 stroke on the dingy.

The issue is a small prop designed for planing speed small boats like dingys. They make a “ sail drive” outboard with larger prop and reduction gear to swing it. That is what you need. A 6 with a speed prop and gear ratio is extremely marginal. Could it do it. Yes in perfect conditions and I mean perfect. I would want an OB geared for sailboats. Or better yet, fix the diesel any way you can. A friend recently bought a used Kabota for 4K. Great engine in great shape.
Happy voyaging.

[Dooglas]

Well, I presume you are asking for advice. I never advise anyone else to try something I would not do myself. I have owned several under 30' sailboats which were specifically set-up for OB power. I have owned 2 larger sailboats which which were not configured for OB power. If the diesel auxiliary failed on either of the larger boats, it is certainly possible to move and manuvuer the boat around a marina or harbor with a dinghy secured at the stern quarter as others have pointed out. I did this myself once when a transmission failed. Worked fine to get the boat to the repair facility. What I did not, and would not, do is set out on a coastal cruise without a workable and reliable system of auxiliary power. If I owned your boat, I would repair or replace the diesel auxiliary.

[MicHughV]

A long time ago, I knew a guy that built a 36' trimaran. He arranged to have a 15 hp Honda 4-stroke in a well under one of the cockpit seats, probably 10' in from the stern. The Honda was a 4 stroke, big prop, leg extension, etc. He thought he had all the bases covered. Ok, it did require gasoline to run, probably it's only weak spot.

The tri performed well under power in calm water, but when the waves picked up, he failed to realize that that the height of a wave under the ama' would also be noted in his outboard well, under the cockpit seat in addition the wave would slop around inside the well and spill over the sides of the cockpit seat.

The experiment was short lived and was soon replaced with a diesel.

The issue isn't really whether an outboard can push a boat, but the practicality of such an idea is limited.

Sailing on a lake or river, or other calm stretch of water, this may be all you need, but this is simply not a practical idea for ocean or coastal areas.

[LargeMarge]

Originally Posted by Mara Mae

...acerbic and disparaging remarks...flawed premises and false assumptions...pompous oneupmanship.

.
These are going on my new business cards... thanks!

[GrowleyMonster]

6HP is pretty small for a 38 foot boat. I would go 15 to 20 HP. You will need an outboard bracket for your transom, installed low enough to keep a long shaft outboard's prop deep enough in the water to avoid near surface cavitation. You may want a prop change, too, lower pitch and bigger diameter. The outboard will be down pretty low and you won't be able to steer effectively with the outboard tiller. No big deal making way, but a big deal when docking. Going down the channel you can steer with your rudder just fine, with the outboard locked in position. You will need a way to take it out of gear or put it in reverse. So, you will at least need control cables for gear shift and throttle, if not for steering. Also you will want a davit for lifting your outboard up off the bracket and into the cockpit or onto a storage bracket.

Your outboard mount needs to be a good one, designed for a heavy outboard. It will be awkward enough just reaching down and unlocking it. Most good mount systems can lift it all the way up out of the water using heavy springs. That will make it easier to attach whatever lifting sling you rig together for bringing the outboard up into the boat.

You will have to decide how and where you will store your gasoline, too. Not a trivial consideration.

All in all, it is not really super practical. In an emergency you can make up the dinghy on the hip, or else tow your boat astern from the dinghy. But this isn't an emergency.

It is almost certain that repairing or possibly replacing your diesel will be overall the better way to proceed. It could be very handy to have an outboard mount and control cables set up so you COULD push your boat with your outboard, but I wouldn't be a fan of relying on the outboard as primary propulsion. When I bought my old Cal 2-27 after Katrina, the Atomic 4 was not running. I wanted to go sailing the next day, so I bought a mount and a new 6HP Tohatsu. Even on that small of a boat, I found steering with the outboard tiller to be very awkward. It got me in and out the harbor, but it was a PITA. Eventually I got the Atomic running nicely, and later when the fuel tank sprang a huge leak, I replaced it with electric propulsion, I kept the outboard mount and the 6hp as backup for quite some time, and I started it and ran it a little every month or so. But I was glad I never had to use it. Your boat is quite a bit bigger than the old Cal so even more difficult to manage an outboard. In dead calm conditions and protected waters, you could literally use a trolling motor or use an oar as a paddle, but that will be like 2% of your powered operation.

If your diesel is so far gone that it can't be salvaged, you could replace it with a Beta diesel fairly (I should say relatively) cheap, or with a used or salvaged diesel of similar power and footprint. Or go electric. One of the biggest misconceptions in yachting is that EP is expensive. I converted my Cal to electric for about $2300 including batteries.For around $6k you could have a fairly nice EP setup, and for a bit more, have enough solar so that over the course of a voyage you could tank up again on the propulsion bank charge, from the sun. You also of course avail yourself of any chance to charge from shore power. All things considered, it is better than an outboard, and possibly a good enough fit for you, to make it more attractive than replacing your kaput diesel. But if your present diesel can be repaired, that, IMHO, is by far your best option.

CAN you use a 6hp outboard to get your boat to open water where you can sail? Yeah, if you pick the weather carefully, and nothing happens. CAN you then dock your boat with your 6hp outboard, at voyage end? Yeah, though there is always extra uncertainty coming into an unfamilar harbor or even an unfamiliar slip, and you still have to pick your weather, maybe hold up on the hook for a day or a few. SHOULD you, is a different question. My OPINION, knowing only what I know about your situation, is you should not and I would not. But my opinion is worth just about what you paid for it so don't let me stop you.

[Estica]

And if all of a sudden some other boat pulls out of a slip and you need to make a u turn, or there is a gust of wind as you emerge around a corner …. How are you going to do emergency maneuvers???? The throttle and gear shift will be nowhere’s near the cockpit seats.

Fix the diesel. Don’t take chances with others boats in a marina. Thank you.