Which / what aux engine

[Orwell boy]

Originally Posted by jeffstevens763@g

Not sure what you mean but my aux was a short shaft way up on the deadrise still in water when down and well clear of the road when towing

sorry ,just thinking the leg of the main outboard offers significant resistance when poweriing against a strong tidal flow (this occured to me after several miles towing and the tow ee raised his outboard and from then on the towing was much easier ) ,i am thinking that it therefore must be a horse power consideration ( for aux choice ) if this is the only option availiable too you having to leave the main leg down for steering ?

[jakew009]

Originally Posted by Limecc

The design will be super strong having four fixing feet. I prefer thicker nylon vs 6mm nylon of a chopping board. Also it's thick wall tube, not sure my own pipe bender will handle it.

Copying the bracket shown below:

Oh I see. My minimalist design calls for just a single tube coming out of the transom and around the swim deck. I don’t think I need it to go up / down if I get a long shaft motor.

[Limecc]

Originally Posted by jakew009

Oh I see. My minimalist design calls for just a single tube coming out of the transom and around the swim deck. I don’t think I need it to go up / down if I get a long shaft motor.

My thinking is short shaft. Prop doesn't need to be the same depth as the main engine, only needs sufficient coverage when the boat is at rest. I doubt my 5hp? engine will provide any stern lift even under max power. Want the engine to be as clear as possible when raised because it's a fixed bracket, also a long tilted leg might be vulnerable when manoeuvring in river locks so want to minimize any sticky out bits.

[jeffstevens763@g]

Originally Posted by Orwell boy

sorry ,just thinking the leg of the main outboard offers significant resistance when poweriing against a strong tidal flow (this occured to me after several miles towing and the tow ee raised his outboard and from then on the towing was much easier ) ,i am thinking that it therefore must be a horse power consideration ( for aux choice ) if this is the only option availiable too you having to leave the main leg down for steering ?

ha i see post 7 my old boat not much room hence main leg to steer

[jakew009]

Does anyone have an opinion of Merc 9.9 vs Suzuki 9.9 EFI?

They are both a similar price but the Suzuki doesn’t have a carb. The non EFI Suzuki is slightly cheaper.

The only advantage of the Merc is it would match the main engine.

Merc does an EFI but it’s much heavier as sedated 15hp.

In terms of shaft length, I assume that as long as the prop is below the bottom of the hull, it doesn’t matter how long it is?

[Limecc]

Originally Posted by jakew009

Does anyone have an opinion of Merc 9.9 vs Suzuki 9.9 EFI?

They are both a similar price but the Suzuki doesn’t have a carb. The non EFI Merc is slightly cheaper.

The only advantage of the Merc is it would match the main engine.

Merc does an EFI but it’s much heavier as sedated 15hp.

In terms of shaft length, I assume that as long as the prop is below the bottom of the hull, it doesn’t matter how long it is?

Suzuki EFI over Mercury carb wins it for me all day long. If you get a used one then 9.9hp out of an engine designed for 20hp means it's never going to have had a hard life. If you buy new then derestriction is always an option in the future.

Here are the three components needed to liberate it: (an easy 10min fit)
Suzuki 9.9/15->20hp efi parts:
13710-89L00 Flame Arrestor $10
13832-89L00 Silencer Seal $8
33930-89L20 Engine Control Unit $422

A decal kit will match it to the main engine.

You may not need a long shaft, it's only operating at displacement speed so short shaft is an advantage if there's sufficient depth to avoid prop ventilation.

[jeffstevens763@g]

Originally Posted by jakew009

Does anyone have an opinion of Merc 9.9 vs Suzuki 9.9 EFI?

They are both a similar price but the Suzuki doesn’t have a carb. The non EFI Suzuki is slightly cheaper.

The only advantage of the Merc is it would match the main engine.

Merc does an EFI but it’s much heavier as sedated 15hp.

In terms of shaft length, I assume that as long as the prop is below the bottom of the hull, it doesn’t matter how long it is?

i found on the 24 degrees deadrise the short shaft prop was in full water next to the tube.

[jakew009]

Originally Posted by jeffstevens763@g

i found on the 24 degrees deadrise the short shaft prop was in full water next to the tube.

I’m thinking if I could get away with a short shaft I may go for a 6hp instead which I could store in a locker and only deploy when necessary. I could then use it on an inflatable tender too.

I know that it’s arguably better to have it immediately ready to go on the transom, but I don’t think it would be too difficult to put a ~25kg outboard on a bracket on the boarding platform.

The 6hp would have integral petrol tank too...

[jeffstevens763@g]

Originally Posted by jakew009

I’m thinking if I could get away with a short shaft I may go for a 6hp instead which I could store in a locker and only deploy when necessary. I could then use it on an inflatable tender too.

I know that it’s arguably better to have it immediately ready to go on the transom, but I don’t think it would be too difficult to put a ~25kg outboard on a bracket on the boarding platform.

The 6hp would have integral petrol tank too...

i tried that i found the 4hp pretty awkward and the time to deploy when you need it sharpish the deciding factor for me

[jakew009]

Originally Posted by jeffstevens763@g

i tried that i found the 4hp pretty awkward and the time to deploy when you need it sharpish the deciding factor for me

Interesting. I wonder if I can buy one with a return policy so I could try it out for awkwardness.

Using it is going to be incredibly awkward anyway because I'm going to have to lean over the rear bench seat somehow - it really is going to be a means of last resort. But I'd rather crawl in at 3 knots for 2 hours than have the RNLI out

I suppose I can always put it on the transom before a higher risk trip so it's ready to go..

[jeffstevens763@g]

Originally Posted by jakew009

Interesting. I wonder if I can buy one with a return policy so I could try it out for awkwardness.

Using it is going to be incredibly awkward anyway because I'm going to have to lean over the rear bench seat somehow - it really is going to be a means of last resort. But I'd rather crawl in at 3 knots for 2 hours than have the RNLI out

I suppose I can always put it on the transom before a higher risk trip so it's ready to go..

if you have an A frame you could tie a rope to the engine take a turn around the A frame lower into position tie off and clamp up. i did all sorts even had two outboard brackets end on to be able to steer the AUX but for me i found on the transom and steer with the main the best option. You can bet when the main engine fails youll be next to the rocks sods law

[jakew009]

Originally Posted by jeffstevens763@g

if you have an A frame you could tie a rope to the engine take a turn around the A frame lower into position tie off and clamp up. i did all sorts even had two outboard brackets end on to be able to steer the AUX but for me i found on the transom and steer with the main the best option. You can bet when the main engine fails youll be next to the rocks sods law

Yes I could definitely use the A frame to help.

I want to be able to steer with the aux as one of my worries is blowing a hydraulic pipe or something and loosing the steering.

Agree re rocks but.. at the moment I have nothing but an anchor

[jeffstevens763@g]

i did this to store the AUX with the intention to make the bracket slide down the frame into position and clamp up bit like a jockey wheel food for thought

[neil.mccrirrick]

I’ve gone through very similar thought process. In the end I’ve determined it needs to be mounted on the transom and left there. It’s all well and good fixing in place in calm seas, I reckon if I really needed it and dropped it over the side I’d have to go as well [emoji1]

No idea about steering yet as this will be new to me but I figure at under 5mph there will be plenty of time to work that out either by use of the main engine or if the tiller is in the way tilt ur up and just turn the entire engine

At 6hp it won’t be that hard

[jakew009]

When I looked at it today I think I’ve actually got loads of space to mount the engine and a short shaft will easily be long enough to reach the water.

So I think my plan is a solid bracket attached to the transom the curves up around the bathing platform. And then stick a 6hp self contained short shaft engine on it that can be stored in a locker if necessary and do for a dingy as well.

[Limecc]

Originally Posted by jakew009

When I looked at it today I think I’ve actually got loads of space to mount the engine and a short shaft will easily be long enough to reach the water.

So I think my plan is a solid bracket attached to the transom the curves up around the bathing platform. And then stick a 6hp self contained short shaft engine on it that can be stored in a locker if necessary and do for a dingy as well.

Good plan. Looking at the pic below it definitely needs a custom bracket. How will you stop the engine bouncing around in the locker through a chop?

[jakew009]

Originally Posted by Limecc

Good plan. Looking at the pic below it definitely needs a custom bracket. How will you stop the engine bouncing around in the locker through a chop?

I think I will make some sort of foam padded compartment loosely moulded to the shape of the outboard. Not 100% sure yet. Plenty of space under the rear bench seat.

[pilotwillie]

Originally Posted by jakew009

I think I will make some sort of foam padded compartment loosely moulded to the shape of the outboard. Not 100% sure yet. Plenty of space under the rear bench seat.

If there’s the height in the locker you could make an arrangement so you can use its clamps to secure it, like onto a horizontally mounted transom bracket. Think I remember seeing pics on here somewhere of a similar arrangement across the open aft deck area of a RIB. Best place is still on the transom though, especially if you have the space. Be much easier to transfer from there onto a waterborne dinghy as well.
As said before, you’d really struggle to move and mount the aux over the top of a bench and onto a transom bracket in any sort of a sea, in an emergency situation or not.

[jakew009]

Just ordered a 6hp Mercury 4 stroke.

I know it's a bit less than the 1hp/m rule (0.8 in my case) but I figured if 6hp won't get me anywhere 9.9 probably isn't going to do much better.

The 6hp engine will be much more manageable to man handle onto a dinghy and importantly for me was the biggest engine I could get with a built in fuel tank.

Still need to sort the bracket though. Planning on offering it up to the boat and then working out what the bracket needs to look like...

[HDAV]

Originally Posted by jakew009

Just ordered a 6hp Mercury 4 stroke.

I know it's a bit less than the 1hp/m rule (0.8 in my case) but I figured if 6hp won't get me anywhere 9.9 probably isn't going to do much better. ...

Presumably for sometime in 2057?

Or did find actual stock on the shop floor ready to go?