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Old 24 September 2020, 11:29   #1
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More Ullswater Sibbing...

Well.. In the last few weeks I've managed Ullswater twice and Coniston once!

First trip to Ullswater ended up being under oar power as the 8hp Yam wouldn't pump water! FF to last weekend and me and my lad had a great day out in the Yam310sti, cruising the length of the lake and back and anchoring in a small bay for a spot of sustenance en route.

Prior to that, the missus and I had a great day on Coniston - all the above after the outboard had the salt deposits that were choking it removed!

The conclusion I have come to is the Yam310sti is a cracking little SIB, as is the 8hp Yam 2 stroke. Unfortunately I noticed that the boat will accept up to a 15hp engine so, the question is, do I look to upgrade?

I noticed what I think was a little cavitation towards full throttle (planing at around 13/14mph). Any thoughts on eradicating this? When bouncing in the chop the prop seemed to lose 'grip' as it were...

In all, two brilliant weekends were had! Click image for larger version

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Old 24 September 2020, 11:46   #2
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Great pics, looks like a good day.

Losing prop grip intermittently can be a feature of air floors. After the usual "are you sure the boat was up to pressure and rechecked after putting in the water" thoughts about all you can do is to try different outboard trim positions and experiment with weight distribution in the boat.

Nothing is certain with different combos but there is the possibility greater power would expose this issue even more.
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Old 24 September 2020, 12:53   #3
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The weight of a 15 hp is not to be sniffed at. If it is a 2 stroke it will be about 40kg. How does this compare with your 8hp
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Old 24 September 2020, 13:21   #4
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Looks like great fun, Sorry i cant help but i do have a question. Id like to get out on Ullswater do i need to register the boat with them? i have been searching online this morning and haven't had much luck! I will have it insured.

Cheers.
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Old 24 September 2020, 15:24   #5
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Originally Posted by AeroAlex View Post
Looks like great fun, Sorry i cant help but i do have a question. Id like to get out on Ullswater do i need to register the boat with them? i have been searching online this morning and haven't had much luck! I will have it insured.

Cheers.
No need to register.

We launched from Glenridding. Just turn up, pay for parking (£8 day) and away you go.

It's my favourite lake. I have insurance but I don't think it's mandatory. If you need any more info just ask or feel free to PM.
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Old 24 September 2020, 15:25   #6
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The weight of a 15 hp is not to be sniffed at. If it is a 2 stroke it will be about 40kg. How does this compare with your 8hp
That was my concert tbh.

Mine is around 27kg and I have a trolley that copes with up to 70kg.

I think 40kg is on the limit..

Any thoughts chaps?
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Old 24 September 2020, 15:47   #7
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That was my concert tbh.

Mine is around 27kg and I have a trolley that copes with up to 70kg.

I think 40kg is on the limit..

Any thoughts chaps?
I have a

3.5 hp Yam 2 Stroke = About 16 kg I think

9.8 Tohatsu 2 Stroke = 26 KG

15 HP Merc 2 Stroke = 40 KG

20 HP Merc 4 Stroke = About 50kg

I can lift all but to be honest the 20 hp is too much and can easily cause injury. Even the 40 kg can cause an issue if you dont do it right.

The extra speed you get over the 9.8 is not that much to be honest
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Old 24 September 2020, 19:43   #8
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Looks like great fun, Sorry i cant help but i do have a question. Id like to get out on Ullswater do i need to register the boat with them? i have been searching online this morning and haven't had much luck! I will have it insured.

Cheers.
No you don't need to register and I would always advise insurance.

There are 3 places to launch on Ullswater:-

Glenridding Ferry Slip - don't pay for parking until you are set up and ready to launch. Personally I prefer to launch from here as there are toilets, secure i'sh parking, coffee and walk for a pint after a day on the lake.

Park Foot - Pooley Bridge. Pay £5 parking and a slip on a campsite.

Howtown - free, can be difficult to park and its a bit remote (car wise)
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Old 24 September 2020, 19:58   #9
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"The conclusion I have come to is the Yam310sti is a cracking little SIB, as is the 8hp Yam 2 stroke. Unfortunately I noticed that the boat will accept up to a 15hp engine so, the question is, do I look to upgrade?"

I think it all depends how you want to use your SIB and where you will predominantly use it.
If you are going to be using it mostly in the Lakes and only 2 up, I'd stick with your current 8hp Yam. Remember it's a 10mph speed limit throughout the whole of the Lakes and possible big fines on Windermere and Coniston if you are caught persistantly over the speed limit (although in practice it's only on Windermere where its strictly enforced)
However, if you are going to be more than 3 up most of the time in the Lakes and/or using the SIB in the sea, estuaries, lochs and Lakes then maybe an upgrade would be benificial. But (there's always a but) weight has to be taken into consideration. I've got a Mercury 15hp EFI 4 stroke which comes in at 47. 5 kg I can manage it, but in 5 years time - who knows.
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Old 25 September 2020, 11:16   #10
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Originally Posted by Flamair View Post
No need to register.

We launched from Glenridding. Just turn up, pay for parking (£8 day) and away you go.

It's my favourite lake. I have insurance but I don't think it's mandatory. If you need any more info just ask or feel free to PM.
Thanks very much! great info. Im looking at parkfoot so ill make sure i have my insurance, good practice imo. and away we go.
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Old 25 September 2020, 11:25   #11
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Originally Posted by Steve509926 View Post
No you don't need to register and I would always advise insurance.

There are 3 places to launch on Ullswater:-

Glenridding Ferry Slip - don't pay for parking until you are set up and ready to launch. Personally I prefer to launch from here as there are toilets, secure i'sh parking, coffee and walk for a pint after a day on the lake.

Park Foot - Pooley Bridge. Pay £5 parking and a slip on a campsite.

Howtown - free, can be difficult to park and its a bit remote (car wise)
Thanks for the tips, ill be sure to check them out. I could do there and back in a day if we wanted so handy to have some other spots to park, inflate and get out from.
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Old 25 September 2020, 14:09   #12
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Quote:
Originally Posted by Flamair View Post
Well.. In the last few weeks I've managed Ullswater twice and Coniston once!

First trip to Ullswater ended up being under oar power as the 8hp Yam wouldn't pump water! FF to last weekend and me and my lad had a great day out in the Yam310sti, cruising the length of the lake and back and anchoring in a small bay for a spot of sustenance en route.

Prior to that, the missus and I had a great day on Coniston - all the above after the outboard had the salt deposits that were choking it removed!

The conclusion I have come to is the Yam310sti is a cracking little SIB, as is the 8hp Yam 2 stroke. Unfortunately I noticed that the boat will accept up to a 15hp engine so, the question is, do I look to upgrade?

I noticed what I think was a little cavitation towards full throttle (planing at around 13/14mph). Any thoughts on eradicating this? When bouncing in the chop the prop seemed to lose 'grip' as it were...

In all, two brilliant weekends were had! Attachment 135224Attachment 135225Attachment 135226Attachment 135227Attachment 135228Attachment 135234
I can't answer the question ref engine size as its what you want from your day out. I have got the Tohatsu 9.8 2 stroke and it's a beauty and only weighs 27kg I think which makes it super easy to get set up without struggling, which is key to me.
Where did you launch on Coniston and is it a good day out?
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Old 25 September 2020, 17:18   #13
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I can't answer the question ref engine size as its what you want from your day out. I have got the Tohatsu 9.8 2 stroke and it's a beauty and only weighs 27kg I think which makes it super easy to get set up without struggling, which is key to me.

Where did you launch on Coniston and is it a good day out?
We launched from Coniston Boating Centre just to the south of the village on the western shore of the lake. It was pretty busy, but was a sunny Saturday in August so to be expected.

Facilities available are food/toilets and reasonable parking.

We did the length of the lake, anchored in one of the bays at the southern tip and ate our picnic before tootling back up.
Depending on the wind, Coniston can be a tad choppy. It was pretty bouncy on the return leg. Good fun though!
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Old 26 September 2020, 09:38   #14
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Originally Posted by Flamair View Post
The conclusion I have come to is the Yam310sti is a cracking little SIB, as is the 8hp Yam 2 stroke. Unfortunately I noticed that the boat will accept up to a 15hp engine so, the question is, do I look to upgrade?

I noticed what I think was a little cavitation towards full throttle (planing at around 13/14mph). Any thoughts on eradicating this? When bouncing in the chop the prop seemed to lose 'grip' as it were...
Personal choice. I have the same size of boat with a 9.9 hp 4 stroke and a 3 hp 2 stroke. I've had as much fun with each size of engine. I don't spend all my time whizzing about flat out, so I wouldn't go for a bigger engine than I need to get the boat on the plane. 9.9 will plane with 2 adults + kit.

Cavitation is when the blade of the prop creates such a strong area of low pressure that gasses dissolved in the water form bubbles, a bit like when you take the top off a lemonade bottle. Cavitation can damage the surface of your prop blades.

What you probably have is simply aeration, which is when air is drawn into the propellor. Either the motor is mounted too high (unlikely because on small SIBs the engine tends to hang low unless you put blocks under the clamp) or it is the interaction of the hull and prop. Check the floor/keel pressure, and maybe adjust the height of the engine with blocks, and experiment with the tilt. 1 "notch" of tilt makes the difference between my engine planing the boat nicely, and it skidding and throwing water everywhere.
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Old 26 September 2020, 11:20   #15
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>>>Mine is around 27kg.... I think 40kg is on the limit.

Weight is quite an individual decision and I find a small amount up or down around the 40kg mark can make quite a difference to portability and when considering the latest 4-strokes of 15hp plus they are more bulky with smoother faired in designs that can be harder to handle.

There's no doubt weights of 26/27kg like the OPs Yamaha 8hp or a Tohatsu 9.8 2-stroke are a pleasure to handle. Then the 15hp 2-strokes (like my Yamaha or the Mercury/Mariners) at 36kg are reasonable for most folks and the 10hp range modern 4-strokes at 37/38kg are similar.

However for me and many folks doing a daily setup a modern 20hp needs much more care... their weights are often stated dry and it's been found higher if you weigh them with oil in... something like the Suzuki DF20A spec'd at 44kg can be 46kg in real life.

For many that weight just tips it into being a two person lift to be sensible unless moved with almost no distance from car to trolley to SIB each time. We managed our DF20A like this but a couple of occasions needing to get it off the SIB on a greasy slipway without the trolley and where a two person lift was awkward made me realise it was difficult enough to accidentally drop or cause back strain so we downshifted back to the 36kg range.
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Old 26 September 2020, 21:32   #16
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In my view the 'extra' power of a 20 hp over a 15 hp is not worth the weight difference.

So for me the 15 hp 2 stroke is the sweet spot if you want nice power. The 9.8 is also fine in this regard.
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Old 26 September 2020, 23:00   #17
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Thanks for all the insight guys.

I'm going to stick with the 8hp I think - for now...

Reason being is that I think it will do for the next year or so and then I'll upgrade the whole outfit for a 4m+ sib/rib with something like a 25-40hp set up. On a trailer obviously.
I think the extra puff of a 15 may be wasted with the 310sti as most of my sib-ing is in the Lakes with the speed limits. However, I do plan to do some estuary work (Devon/Cornwall) once the Covid shenanigans are over.
Thanks again. More reports to follow as and when.
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