Swim deck outboard motor mount and other questions

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.

Alaskasbear

Veteran Member
Joined
Jun 10, 2016
Messages
58
Location
United States
Vessel Name
Slow Goin
Vessel Make
78 MS 34 Mk1
Does anyone have an outboard motor mount on their swim deck for auxiliary power. Here in Alaska tugs and sea tows are far and few between. Better to be self sufficient when it comes to single screws. I'm looking for brand names and hp rating. Around a 15 hp ideally so i can use the motor with my 13 ft inflatable.
Question 2
Where the heck is the engine zinc on a perkins t6.354m. Can't seem to find it in my manual.

Question 3
PO had never greased intermediate bearing on my mainship 34 mk1 shaft flexes where it glues through it. Is it a simple matter to just remove the coupling to the transmission and sliding the shaft back to replace the bearing? And then pushing it back in to reinstall coupling?

Question 4.
Zinc on rudder shoe. Mine seems to have none nor did it ever to appear to. There is 1 on shaft and 2 on rudder. But shoe looks like it's pitting. I was thinking on having a welder weld 2 bolts sticking up forward of the prop on the shaft and just custom drilling a welded teardrop to address this issue. Bad idea.
Thanks for any info.
 
Question 2
Where the heck is the engine zinc on a perkins t6.354m. Can't seem to find it in my manual.

Question 3
PO had never greased intermediate bearing on my mainship 34 mk1 shaft flexes where it glues through it. Is it a simple matter to just remove the coupling to the transmission and sliding the shaft back to replace the bearing? And then pushing it back in to reinstall coupling?

Question 4.
Zinc on rudder shoe. Mine seems to have none nor did it ever to appear to. There is 1 on shaft and 2 on rudder. But shoe looks like it's pitting. I was thinking on having a welder weld 2 bolts sticking up forward of the prop on the shaft and just custom drilling a welded teardrop to address this issue. Bad idea.
Thanks for any info.

Question 2 There should be a zinc in the top of the ,main heat exchanger. There may or may not be one in the oil/tranny cooler.

Question 3 Since you have a 1978 boat the bearing is on the forward side of the bulkhead under the sliding glass door, correct? If yes then you can do the job almost as you described. Are you in the water? If so then you cannot slide the shaft back very far, only a few inches. That will be enough to first remove the coupling, then slide the bearing forward and off the shaft. Before you try sliding the bearing or the shaft, there are 2 allen head set screws that secure the inner race to the shaft (to prevent the race from spinning on the shaft) that must be loosened. You'll also most likely need some "persuasion" to get the bearing and or shaft to move. My persuasion came in the form of a 5 pound sledge hammer and some rods (punches) so be prepared. Make sure you use a file to remove any burrs or dings on the shaft.
If you are out of the water then you can remove the prop, then pull the shaft out.

Question 4 There was no zinc on the shoe as OEM. I have seen folks use a shaft zinc around the shoe. That should be easier than welding studs.
 
Does anyone have an outboard motor mount on their swim deck for auxiliary power. Here in Alaska tugs and sea tows are far and few between. Better to be self sufficient when it comes to single screws. I'm looking for brand names and hp rating. Around a 15 hp ideally so i can use the motor with my 13 ft inflatable.


Bad idea. 15 hp is too big to transfer in rough water, but not big enough to get you out of trouble, on your 14000 lb Mainship. And that would be after spending time, effort and money trying to fab a satisfactory mount on your swimgrid and reinforce the SG adequately to hold a 15 in place.

Far better to keep the outboard on the dinghy and tie to the hip. 15 isn't enough to do much more than hold your boat off of the rocks, head to wind, should you run into trouble, so you should think about upsizing your tender to 25 or more hp. Then you can relax in the knowledge that you can actually move your boat where you need to, in rough conditions, should that emergency arise

I had to move my sailboat (8000 lb) when I lost a prop, and 15 on my dinghy, on the hip, was adequate. My next boat was also a sailboat, 16000 lb, so comparable to your MS, the 15 worked, tied at the hip, but that was in perfect weather, when I tried it. I wouldn't have trusted 15 hp to be enough in bad weather or a strong current.

Tying to the hip can be done in rough conditions. Lifting an outboard from the dinghy and transferring it to a SG mounted bracket can't.
 
Last edited by a moderator:
Alaskasbear while you're in the job, remove the grease fitting on the new bearing and install a length of 1/8 inch hydraulic hose with a male fitting on one end to replace the grease fitting (1/8 npt most likely) and a female on the other end. This is now your extension so you can reach the fitting to grease the bearing once a season.
 
Alaskasbear while you're in the job, remove the grease fitting on the new bearing and install a length of 1/8 inch hydraulic hose with a male fitting on one end to replace the grease fitting (1/8 npt most likely) and a female on the other end. This is now your extension so you can reach the fitting to grease the bearing once a season.
Wow excellent idea . You'd think that it would have been built that way .Thank you. And yes I'm in the boatyard so sliding the shaft back shouldn't be a problem.
 
MurrayM installed mount on his swim platform a year or so ago. This thread has a picture of it.
http://www.trawlerforum.com/forums/s6/new-lehr-9-9-propane-outboard-tip-10742.html
I think it is a good idea if you're going to carry an outboard anyway. Easier than towing with your dinghy

Hopcar mentions Murray's OB mount. I duplicated this on our boat with a mounted 9.9 hp Hi Thrust Yamaha. This engine is the equivalent to 15 hp in a standard geared motor. The weight of this engine is approx 100#.
Agree that mounting such a motor on the back of a aux boat while afloat is a challenge. Having some sort of process of shifting such a engine from the main boat to the aux boat that incorporate a swivel crane or boom with two persons involved is a safer concept.

We mount a 6 hp on our 12 foot aluminum skiff which we tow behind. This takes some prep time and logistics however we have found that having this accomplished in port in calm waters, gives peace while underway knowing the setup is ready for momentary action.

Al-Ketchikan 27' Marben Pocket Cruiser
 
Perhaps consider the charging out put of the outboard. May be able to use it to charge a dead (start) battery.
 

Latest posts

Back
Top Bottom