Need for an auxiliary engine on a SIB???

[spartacus]

Originally Posted by stray

What's the smallest, in weight/dimensions, 2 stroke outboard?

Don't know if its necessarily the smallest, but a Tohatsu 3.5hp or Mariner 3.3hp are probably there or there abouts for power to weight ratio. An air cooled early model outboard may be lighter (ear muffs come as standard).

Specification here:
http://www.tohatsu.de/outboard-info/M3-5B2/43

Mariner | All Models

[stray]

Originally Posted by spartacus

An air cooled early model outboard may be lighter (ear muffs come as standard).

Specification here:
M3.5B2 » Outboard-Info » Tohatsu Outboards

Mariner | All Models

Cheers, as a get me home, the noise wouldn't bother me, I'd just stuff a bit of Mackerel in my ears.

[Wild_Bill]

Originally Posted by stray

What's the smallest, in weight/dimensions, 2 stroke outboard?

Probably a Chinese weedeater conversion jobber:

Amazon.com: Outboard Motor 3.5 HP 2 Stroke Inflatable Fishing Boat Engine Fast Shipping: Sports & Outdoors

Of course, it's hell on the environment, and your ears will ring for two days after every trip, but it only weighs 10 kilos.

[stray]

Originally Posted by Wild_Bill

Probably a Chinese weedeater conversion jobber:

Amazon.com: Outboard Motor 3.5 HP 2 Stroke Inflatable Fishing Boat Engine Fast Shipping: Sports & Outdoors

Of course, it's hell on the environment, and your ears will ring for two days after every trip, but it only weighs 10 kilos.

Q: Is this for salt water use?
A:
No fresh water only


That rules that one out.

Do you think one of these would get me home?

http://www.amazon.co.uk/Eteyo-Superi....5+HP+2+Stroke


It'll do 20km/h four up.

[The Gurnard]

At just an ounce or so over 9kg my 2HP yamaha 2 stroker must be a contender for one of the lightest.. centainly a good 3kg - 4 kg lighter than my mariner 3.3Hp 2 stroke, Its not too noisy and very reliable. Its thin profile is great for transom mounting as an aux in small spaces

[azzurro]

Originally Posted by The Gurnard

At just an ounce or so over 9kg my 2HP yamaha 2 stroker must be a contender for one of the lightest.. centainly a good 3kg - 4 kg lighter than my mariner 3.3Hp 2 stroke, Its not too noisy and very reliable. Its thin profile is great for transom mounting as an aux in small spaces

What a lovely spray hood! Will you please post more detailes pics! Is it flexible?

[The Bass Stalker]

Originally Posted by kaman

Had another play with outrigger bracket today.
I have now decided on the final design!
Outrigger engine mounting plate to which engine clamps to be cut in half, I intentionally made it on the large side so I could play around with different set ups.
This will leave a very small engine mounting plate overhanging sib tube, but also serve to reduce the risk of the plate/engine catching on waves.
Surplus plate to be welded / bolted to the top of they outrigger 50mm box section - see pic!
This will serve as an extra transom, to mount engine to.
As this mount is close to the transom engine bearing stresses placed on transom greatly reduced whilst the Sib is on the move.
As can be seen from pic engine carried high clear of the water and on the inside of tube, well within harms way.
Engine to be attached to transom with lanyard at all times!
When needed engine to be unclamped from outrigger and clamped to the removable outrigger engine plate which overhangs left hand Sib tube.

Thanks for latest pics. I look forward to your report on the sea trial. Where you have it now is where I intend to store mine with a bit of 8 x 2 bolted and shaped to the transom. And then when needed( hopefully wont!) I will slide over main engine, remove one of the transom wheels with a single bolt and put auxiliary on transom like 'gurnard' has on his Quicksilver. But I think I can fit on without peeling back rubber splash thing, if I extend the transom a little with some ply cheeks and a triangular block. Lots to do and not enough time! Obviously this isn't as quick as what you are proposing but should work and not have any problems with rough seas, I hope.

[kaman]

Originally Posted by The Bass Stalker

Thanks for latest pics. I look forward to your report on the sea trial. Where you have it now is where I intend to store mine with a bit of 8 x 2 bolted and shaped to the transom. And then when needed( hopefully wont!) I will slide over main engine, remove one of the transom wheels with a single bolt and put auxiliary on transom like 'gurnard' has on his Quicksilver. But I think I can fit on without peeling back rubber splash thing, if I extend the transom a little with some ply cheeks and a triangular block. Lots to do and not enough time! Obviously this isn't as quick as what you are proposing but should work and not have any problems with rough seas, I hope.

That sounds like a plan Bass Stalker.
When you get your project under way post some pics.
I will add the finishing touches to the outrigger this week paint it and mount it.
Probably won't get to try it for a good few weeks though.
Just started another SIB project.
Been making a bow locker for my Honwave.
Going to have a battery compartment anchor compartment and bric a brac compartment.
Hopefully this will offset the weight of two engined and myself sitting at the rear,
I will post some pics in the next few weeks.

[9D280]

Originally Posted by stray

What's the smallest, in weight/dimensions, 2 stroke outboard?

Don't forget the Johnson 2Hp from 1960atcake. Either 7 or 9 Kg (I forget which) and super slim, with a single screw clamp so fits onto the smallest available transom space..... (the twin pot 4Hp version is a dizzy 13Kg fuelled!

...but as said earlier also has an open case, so very prone to brine ingress!

[kaman]

Sib outrigger almost complete. Mounted it today
Should get to try it out over the next few weeks

[kaman]

A few other pics.

[kaman]

Engine mounting plate unfolded for towing and to allow cover to be put over Sib.

[The Bass Stalker]

That does look really good now. The water will never hit it even in the outer position but I guess if you store it in closer in position then it will put less strain on transom. I still wonder if in rougher seas if it will dip in and out of the water but I actually think you will be ok. You could always lower it a couple of inches and I still think it will be safe. Cant wait to hear about your sea trial.
Mine is coming along quite well and I think I have solved it. Being a wood man its all made from timber but I am sure it is strong enough. I have managed to store the outboard in roughly the same inner position as yours. I have then made a aux bracket that extends 10 ", which the transom wheel swings past when it has no engine on so will be fixed with a big bolt through the existing 1" hole in the transom. When and if needed, all I have to do is remove the r-clip and washer from the transom wheel up in the air, put wheel in boat, and move engine across 12" onto aux bracket(which will have a leach so cant be lost!). The aux tiller has nearly full movement left and right, not sure about reverse yet as its all made as mock ups at the moment. Will post some pics soon, If I know how?

[kaman]

Hi basshunter please do post some pics when you got yours operational.
Im going to sika flex the bolts in tomorrow.
I think the final set up should do the job.
If a wave is going to hit the aux when it's carried on the inside of the tube it's going to have to be a monster and my aux getting wet will be the least of my worries!
It has good water clearance when in the outside position as well.
I think conditions will dictate if I use it to rest the main engine whilst trawling for fish. If it is choppy I will just carry it on the inside as emergency back up.
I don't tend to go out when it'd too rough so I think it should be fine fir the purpose I constructed it for.

[The Bass Stalker]

Now having seen the finished article, I cannot see that it will ever get hit by a wave even if it were a few inches lower, and like you say, if that has happened then that's the last of your worries. My only concern would be if you traversing diagonally across chop/, whether it would stay submerged properly but lowering a few inches would solve that if needed. Sibs do stick to the water very well when moving slowly as you know and don't pitch and awe like a dingy so hopefully you should be ok. You never know, you might be able to fit a transom bracket where I have, but I think you'll be fine.

How do I add photos???

[kaman]

I've been using my phone to take photos and post them on here.
When adding photos in this manner just type your reply and hit the add attachment button, select photo and attach.
Ribnet set up varies from device to device.
On the wife's IPad it looks a lot different to my phone with lots more options.
It looks different again on the laptop.
Hit the paper clip to attach photos oan tablet / laptop etc.
Look forward to seeing your creation.

[The Bass Stalker]

[/IMG]Did it work??

[The Bass Stalker]

Trying again? These are the prototype as the exact position of everything was critical so everything could still work

[kaman]

I see you mastered the art of attaching pictures.
Took me a few attempts to attach my first pics too.
Looks good!
Definitely engine on the inside of the tube is preferable to tge outside but my transom was ne cover going to be wide enuf.
The only thing I can see that may cause you an issue is the engine mount on the back of the transom!
With the main 30hp engine at planing speed it may scoop up water and spray it into the Sib.
You know your boat better than me and where everything sits relative to the water etc.
As with mine proof will be in the pudding when it gets sea trialled.
Hope it works.

[The Bass Stalker]

I have already made the real transom bracket which is a bit more streamlined than the prototype. Plus, I have had the vertical piece of wood down the transom for over a year now which has had the transducer attached to it at the very bottom. Its a strong bit of 3/4 inch mahogany. I had to reduce half an inch when I first made it so it didnt stick out at all, because a bit of spray did come up but is now fine. I will post pics of the bracket a bit later. Let me know what you think.

Where do most put there transducers on sibs? Mine has worked ok where I have had it but isn't always great at 20 knts!