mounting an outboard on a ferro transom

[krazy koala]

hello everyone. i am looking at fitting an outboard bracket on the transom of my walker ferro and taking out the tired md1 diesel. what i need to know is : if i drill the holes with a masonry bit and seal bolts with sika and fit a large steel plate inside to distribute the bolt loads will it be strong enough. it is a 25 merc 2 stroke so engine weight is pretty light.

[David_Old_Jersey]

No expert on Ferro - but I would also go for a "backing plate" on the outside to also distribute the loads (although I guess that depends on bracket design). My initial thought would be a lump of timber, or even Marine Ply for both sides.

Might also want to bear in mind that you might hit steel when drilling through.

[krazy koala]

thanks for the reply, never thought of ply, a piece of 19mm inside and out would spread the load. i should be able to grind a metal cutting face onto the masonry bit, i think i have done that before for drilling hardened steel. i think the blade tip on a masonary bit is titanium.

[bruce smith]

Have you considered what the engine will do when the boat heels,or goes fast downwind?
Not that I am a fan of md1. That will be a tough life for a 2 cycle with electronic bits under the roof. 115 lbs is not so easy to pop on n off.
Then there is the stereotype of the ferro boat to deal with. Bolting a too large ob on her is a typical amateurish thing to do. A 3500 lb boat may do fine with a 6 or a 10.

[krazy koala]

Originally Posted by bruce smith

Have you considered what the engine will do when the boat heels,or goes fast downwind?
Not that I am a fan of md1. That will be a tough life for a 2 cycle with electronic bits under the roof. 115 lbs is not so easy to pop on n off.
Then there is the stereotype of the ferro boat to deal with. Bolting a too large ob on her is a typical amateurish thing to do. A 3500 lb boat may do fine with a 6 or a 10.

what has heeling or going down wind got to do with it. my boat is 3500 kg not pounds. a 6 or 10 will be useless against the tide or wind. i have a 25 already with fwd controls and electric start, it will push the boat easily at hull speed about 6 knots. i don't plan on removing it each outing. hate to be rude but you just gave me a load of useless info. i was asking about drilling and mounting a bracket.

[Bash]

Originally Posted by krazy koala

hello everyone. i am looking at fitting an outboard bracket on the transom of my walker ferro and taking out the tired md1 diesel.

Yikes. Think long and hard about this. The moment you replace that diesel with a bolted-on outboard, the resale value of your boat becomes absolute zero. You won't be able to give it away.

[krazy koala]

Originally Posted by Bash

Yikes. Think long and hard about this. The moment you replace that diesel with a bolted-on outboard, the resale value of your boat becomes absolute zero. You won't be able to give it away.

its a ferro so its not exactly worth big dollars. but i don't think it should adversely affect the value. think of the extra storage where that old vibrator used to sit and no prop drag while sailing. ease of removal for service. outboards have a lot advantages especially 4 strokes.

[bruce smith]

Originally Posted by krazy koala

what has heeling or going down wind got to do with it. my boat is 3500 kg not pounds. a 6 or 10 will be useless against the tide or wind. i have a 25 already with fwd controls and electric start, it will push the boat easily at hull speed about 6 knots. i don't plan on removing it each outing. hate to be rude but you just gave me a load of useless info. i was asking about drilling and mounting a bracket.

Heeling and going fast downwind have to do with the ob going underwater.
In your other thread , you said the boat was 3500 TONS! and you mentioned how fast it was , so I assumed 3500 pounds. " i laugh at some of the posts on this site classing ferro as slow and heavy. this boat is 3500 ton"
Of course I do not think it will come off n on each time, especially being 115 pounds!

tide has no effect on boatspeed, unless you run aground in a falling one.
Anyway, you are talking about 4 bolts, A chunk of steel may dig in at the corners. Plywood would be better, but it would really be a bushing. A few laminated pieces of solid wood would form to the hull and carry the load away from the stone.

[krazy koala]

Originally Posted by bruce smith

Heeling and going fast downwind have to do with the ob going underwater.
In your other thread , you said the boat was 3500 TONS! and you mentioned how fast it was , so I assumed 3500 pounds.
Of course I do not think it will come off n on each time, especially being 115 pounds!

tide has no effect on boatspeed, unless you run aground in a falling one.
Anyway, you are talking about 4 bolts, A chunk of steel may dig in at the corners. Plywood would be better, but it would really be a bushing. A few laminated pieces of solid wood would form to the hull and carry the load away from the stone.

3500 ton probably would be a bit heavy, i should have typed 3500 kg. the engine will be in the middle which will help with heeling, plus i want to use a lift up bracket. i should have said tidal current , the 7 hp md1 goes no where when i hit it. thanks for the mounting tips, laminated to the transom curve will be the way to go.

[krazy koala]

don't forget there are thousands of outboard powered traier sailers , they don't have dramas with heeling or running down wind.

[David_Old_Jersey]

Originally Posted by krazy koala

3500 ton probably would be a bit heavy, i should have typed 3500 kg. the engine will be in the middle which will help with heeling, plus i want to use a lift up bracket. i should have said tidal current , the 7 hp md1 goes no where when i hit it. thanks for the mounting tips, laminated to the transom curve will be the way to go.

I can understand why you want a bit more oomph than 7hp (I too live in a tidal area) and given the boat and likely value an i/b is probably the only cost effective route to add some more poke. But, at the risk of stating what you already know!, the big downside (vs an inboard) will be the prop cavitation whenever the sea gets a bit bumpy as the o/b prop won't as deep as with an i/b and will sometimes even be airborne! (which of course affects performance!, even when not actually fully airborne)......not to say that is not doable, but an O/b (esp. simply on the stern) is not ideal to use on passage, at least not for extended periods when can't pick the weather so easily.

But boats is all about compromises and choices .

[krazy koala]

yes david, that is the only disadvantage but i sail on a lake system here, there is no swell to worry about.

[ferrosailer]

Hi
I have a Samson ferro C-Shell 36ft in the hull witha 2qm yanmar. seem to have a gear box issue (YP7) which may have been incorrect alignment (compressed engine mounts) I have sinced replaced them and rebuilt the box all seems good.
I have considered a transom out board auxiliary as a back up and was curious if your project turned out and how you went about it.
Also what sort of fuel usage do you get.
Cheers

[Mattyb]

Hey ferrosailer I have the exact same yacht and motor! Would love to see some pics if u have any. Mine is 1990 built.

Sorry for going off topic

[krazy koala]

hi ferro sailer, i have not gone ahead with it yet but i can't see it being a problem if you follow the advice in this thread, i liked the idea of laminating a timber backing plate to match the transom. because your boat is quite big you need to consider operating the out board. whether you use remote controls and fix the engine straight ahead or rig up some sort of remote steering as well, that would be my preference.