My little 2.5hp Four Stroke

[Croolis]

Hello all, new to forum <wave>. UK bloke .

Recently bought my first outboard, a new 2.5hp 4 stroke Mariner. I'd intended to use it on my Mirror sailing dinghy, but once I actually had the thing in hand, decided it might be too much weight for the wooden transom on 50 year old home built boat so decided what the heck, I'll buy a SIB.

Another factor in this decision is that my 11 year old has a fear of tipping in a sailing dinghy, really freaks out, won't sail. But doesn't mind being in the big RIB safety boat at the sailing club (we sail on a reservoir).

So now we have a Boatworld 3.2m air deck to go with the 2.5hp. This year we will be doing river/lake cruising locally in Nottingham area. So Trent/Soar (Rutland?) Would also like to do Broads, Lake district, but all the damn fees are shocking when you add them all the up all the different authorities. I'd like to sail on all of them. I'm also from Dartford way so when I'm down there visting, Medway and others could be an option.

EDIT: no not Rutland. Apart from rivers/canals, not actually a lot of inland locations in UK, is there?

I have started running in process on the engine in a wheelie bin of water, idling in neutral. Have done an hour. This weekend I am planning on taking it to a canal to do more but in gear. Was advised by helpful mechanic at Boatworld that running in under load would be better.

I'm in Nottingham area. Will likely go Sawley Marina and pootle up and down that bit of canal there (anyone want to come and have a laugh at amateur night, feel free ). I would also welcome any advice on where to go locally for a pootle. Slipways, beaches and the like. I don't have any transom wheels yet but that is high on priority list (an 11 year old isn't much help carrying Big Stuff). I do have a set of skates that I will use in a pinch.

Now, here's daft newbie questions: once I get this thing run in (an hour at very low revs still, followed by 8 hours of around half throttle with only short bursts at higher throttle), how do we think 3.2m air deck SIB with 2.5hp will perform in rivers with me and the boy in it? We'll be about 120kg if we bring nothing else. Speed is obviously not going to be a thing, but will we at least make headway upriver? I have these awful visions of being swept towards a weir and not being able to do anything about it lol.

I know rivers can vary of course - in fact the Trent has been high recently with red warnings. I walk to Beeston Marina on my lunch break and it seems to be flowing slower last couple days. I guess the only way to find out is to try it.

I also fancy sailing the thing on estuaries, if I can find somewhere appropriate and with consideration for tides , so any advice on where to go for that, also appreciated.

I only have this 2.5hp because I had intended it as backup for my sailing dinghy, and I'm rather regretting it. But I'm also a single parent and there's no way I'm stretching to a 10hp. Even when I upgrade in a year's time (there's no more funds this year now lmao), it'll only be a 6hp, which will likely be enough to get away with I think?

I'm sort of rambling . Anyone want to just air their thoughts on all this, fill yer boots .

[Limecc]

Did you know you can derestrict your engine for less than £40?

[Limecc]

We're local. Try launching for free at Hazleford instead of Sawley which can come later. You would do well to purchase a British Waterways key, you don't need a windlass unless venturing onto canals.

You'll get away without a license for the first dip as you won't be going far, but later you'll need one to go through locks which are manned, using the BW key after 5pm. Minimum term is 1 week, quite expensive.

You can also launch at Beeston Marina for free, they only charge when they have to swing the bridge over the ramp out of the way.

You can launch on the tidal section at West Stockwith and go upstream to the tea rooms at Torksey. Very pleasant. You need to time the launch by phoning the lockkeeper and Wilf who looks after the ramp at the basin is ok with folk launching for free if he doesn't have to unlock the low chain across the ramp. You can lift your boat over.

[beamishken]

Originally Posted by Croolis

Hello all, new to forum &lt;wave&gt;. UK bloke .

Recently bought my first outboard, a new 2.5hp 4 stroke Mariner. I'd intended to use it on my Mirror sailing dinghy, but once I actually had the thing in hand, decided it might be too much weight for the wooden transom on 50 year old home built boat so decided what the heck, I'll buy a SIB.

Another factor in this decision is that my 11 year old has a fear of tipping in a sailing dinghy, really freaks out, won't sail. But doesn't mind being in the big RIB safety boat at the sailing club (we sail on a reservoir).

So now we have a Boatworld 3.2m air deck to go with the 2.5hp. This year we will be doing river/lake cruising locally in Nottingham area. So Trent/Soar (Rutland?) Would also like to do Broads, Lake district, but all the damn fees are shocking when you add them all the up all the different authorities. I'd like to sail on all of them. I'm also from Dartford way so when I'm down there visting, Medway and others could be an option.

EDIT: no not Rutland. Apart from rivers/canals, not actually a lot of inland locations in UK, is there?

I have started running in process on the engine in a wheelie bin of water, idling in neutral. Have done an hour. This weekend I am planning on taking it to a canal to do more but in gear. Was advised by helpful mechanic at Boatworld that running in under load would be better.

I'm in Nottingham area. Will likely go Sawley Marina and pootle up and down that bit of canal there (anyone want to come and have a laugh at amateur night, feel free [emoji38] ). I would also welcome any advice on where to go locally for a pootle. Slipways, beaches and the like. I don't have any transom wheels yet but that is high on priority list (an 11 year old isn't much help carrying Big Stuff). I do have a set of skates that I will use in a pinch.

Now, here's daft newbie questions: once I get this thing run in (an hour at very low revs still, followed by 8 hours of around half throttle with only short bursts at higher throttle), how do we think 3.2m air deck SIB with 2.5hp will perform in rivers with me and the boy in it? We'll be about 120kg if we bring nothing else. Speed is obviously not going to be a thing, but will we at least make headway upriver? I have these awful visions of being swept towards a weir and not being able to do anything about it lol.

I know rivers can vary of course - in fact the Trent has been high recently with red warnings. I walk to Beeston Marina on my lunch break and it seems to be flowing slower last couple days. I guess the only way to find out is to try it.

I also fancy sailing the thing on estuaries, if I can find somewhere appropriate and with consideration for tides , so any advice on where to go for that, also appreciated.

I only have this 2.5hp because I had intended it as backup for my sailing dinghy, and I'm rather regretting it. But I'm also a single parent and there's no way I'm stretching to a 10hp. Even when I upgrade in a year's time (there's no more funds this year now lmao), it'll only be a 6hp, which will likely be enough to get away with I think?

I'm sort of rambling . Anyone want to just air their thoughts on all this, fill yer boots .

Welcome to the forum, I think you will be surprised how well your little engine will push your boat, It wont win any races but you will still have fun exploring. Regarding current flows just be carefull how flooded the river is before you go, even experienced folk can get into bother when rivers are in full spate. The trick is always head upstream first that way you know you will always get back to your starting point. Re licensing do your research on licence requirements for your type of craft, sometimes small craft attract little or no charge depending on location.
I would definitely run in under load & in use is the way to go , often working a little harder (within reason) helps them bed up quicker just vary the rpm & don't sit at one particular speed for hours. Ive seen folk set them away in a barrel and let them run for hours at one throttle setting , thats not the best way to do it. Get it on the boat and use it at different speeds is the way to go.
Can't help with any suggestions of where you can go locally but no doubt someone will turn up with suggestions. Enjoy!


Sent from my SM-G950F using RIB Net mobile app

[Matt]

For a bit of pootling on canals, 2.5hp will be fine. "Eventually", I think you'd likely want 4-6hp - not to go faster, but just so that you have the engine at a nice cruise speed, not running it flat out all the time.

[Steve509926]

Hi and welcome.

Lake District is free providing you steer clear of Windermere and don't launch from the Boating Centre at Coniston.
Ullswater, Coniston and Derwentwater can be accessed at various points from the road. Derwentwater would be really nice in a small sib with a small OB. Loads of places to explore and stop off. It's pretty much sheltered from the wind unless it's blowing from the NW. It is shallow in parts towards the Grange end, but you won't be going that fast not to notice. Keswick is a lovely town. Top end of Ullswater at Glenridding is another good spot to explore, however, I wouldn't venture beyond Howtown as when the wind gets up you will struggle to get back with a 2.5hp.
Top end of Coniston is another good place to park up and launch.
Sorry, can't help with anything closer to home.

[Croolis]

Originally Posted by Limecc

We're local. Try launching for free at Hazleford instead of Sawley which can come later.

Is that pic the end of Boat Lane? That looks perfect for river launch for me . I have a colleague who rows with Holme Pierrepoint lot who was pointing me at that spot.

Thanks very much replies all, much appreciated. Overall, I'm thinking of using in rivers rather than canals - the canal part is really just for the breaking in of the motor because no flow to worry about when I can't rev up. But it's also true I'll be canals at some point, if I'm doing long trips down the Trent, it's pretty unavoidable. I already own a lock windlass, but not got a canal key yet - guess I need both.

I have seen about the derestricting thing as it goes on my engine, but I read differing views on it. Some people say it's harmless because the engine is built the same whether 2.5hp or 3.5hp, some ppl say it'll stress other parts too much. Some things I read say about injectors, but mine is definitely carbs. I'm not clear about it, though I'd definitely love to squeeze another HP out of it if I can. I take the point about being able to not have to run at top revs even if not trying to go fast.

Better run it in first though!

Thx all for replies.

[Croolis]

Originally Posted by Steve509926

Hi and welcome.

Lake District is free providing you steer clear of Windermere and don't launch from the Boating Centre at Coniston.
Ullswater, Coniston and Derwentwater can be accessed at various points from the road. Derwentwater would be really nice in a small sib with a small OB. Loads of places to explore and stop off. It's pretty much sheltered from the wind unless it's blowing from the NW. It is shallow in parts towards the Grange end, but you won't be going that fast not to notice. Keswick is a lovely town. Top end of Ullswater at Glenridding is another good spot to explore, however, I wouldn't venture beyond Howtown as when the wind gets up you will struggle to get back with a 2.5hp.
Top end of Coniston is another good place to park up and launch.
Sorry, can't help with anything closer to home.

Much appreciated, thank you .

[chipko]

I too think you’ll be pleasantly surprised how well the Mariner 2.5hp will push along your sib. We’ve taken our boats many times on the Trent and often with a tiny Honda 2.3 or Mariner 3.5. These motors happily pushed our T38 along at around 5 or 7 knots respectively two up. No need for full throttle either as around half throttle gives 90% of speed with a far quieter/less frantic ride.
Another decent launch site on the Trent is the free slipway (BW key req’d for barrier) at Farndon near The Riverside pub or for a fee (£20 this year) and facilities the slipway at Farndon Mariner.

[A1o]

Hi mate,

Couldn’t give much advice re Knots as very new to it all, but with a load of about 135kg in a 2.4 Sib we get a decent push in tidal Blackwater estuary with a 2HP..

I never push the limits or my luck, but always felt comfortable with its ability.

[Tommy c]

Chipko is spot on.
You will easily get 5 to 7 knots both on your own and with a passenger, at half throttle too. I have a 3.3hp mariner.
Regards getting an extra 1hp, SimonCH started a thread about fitting a bigger carb on a 3.5 and it seems pointless.

[Matt]

7 knots at half throttle? OK.

Nevertheless, point stands that 2.5 is adequate for a bit of nobbing about in a canal or river.

[chipko]

Without wishing to ‘willy wave’ take a look at post 21 on this thread to see what a tiny 3.5 motor can do on an efficient hull.

Yet another Elling KB350 thread
https://www.rib.net/forum/f50/yet-another-elling-kb350-thread-86374-post837422.html

All our observations are based on actual testing and gps data (two way average generally) and stock 7” plastic prop.

Obviously not claiming those speeds are achievable on the average sib but small motors will easily push these lightweight boats along at the hulls max displacement speeds at relatively relaxed throttle openings. Full throttle often just equates to lots more noise/fuel use with negligible increase in speed

[Steve509926]

Originally Posted by chipko

Without wishing to ‘willy wave’...........

Thanks chipko, working on such a beautiful day, that really made me laugh

[A1o]

Originally Posted by chipko

Without wishing to ‘willy wave’ take a look at post 21 on this thread to see what a tiny 3.5 motor can do on an efficient hull.

Yet another Elling KB350 thread
https://www.rib.net/forum/showthread.php?p=837422

All our observations are based on actual testing and gps data (two way average generally) and stock 7” plastic prop.

Obviously not claiming those speeds are achievable on the average sib but small motors will easily push these lightweight boats along at the hulls max displacement speeds at relatively relaxed throttle openings. Full throttle often just equates to lots more noise/fuel use with negligible increase in speed

Again without pretending I know much, I can defo relate to this I don’t see much difference between full throttle and less, at full throttle it’s a lot louder that’s guaranteed, not sure I get a lot more performance, again only an opinion based on my unqualified observations!!

I’ve got a Yamaha 2B and a Johnson 4HP (1978)

[Fenlander]

Welcome from me Croolis.

I fully agree small motors in the 2-3.5hp range are ideal for non-tidal rivers and canals. They will usually push pretty well any small craft up to the river speed limit. Trying to push above those speeds just results in a daft bow up attitude and antisocial wash.

So in many ways far more suited to your current use than a bigger motor. Then see how you like the whole sibbing thing and if it suits consider that 6hp next year for estuaries and the sea. If you keep your load light that Boatworld 320 should go well enough with a 6hp. Such as this outfit...

https://www.youtube.com/watch?v=gIVdPZ-Iyxw

[beamishken]

Originally Posted by Matt

7 knots at half throttle? OK.



Nevertheless, point stands that 2.5 is adequate for a bit of nobbing about in a canal or river.

[emoji106]3-4kts is more realistic

Sent from my SM-G950F using RIB Net mobile app

[Croolis]

Thanks awfully for all the cool replies. That takes a load of the worry out of it .

Once I finish running in I shall have a wander down to the chandlery at Beeston and ask the question about their slipway for free. When I asked them before about putting my trollied sailing dinghy in there they told me £8.50 each way urrgh, presumably because of the bridge thing. But if free if just carrying in, then I can easily go for a pootle after work . Sawley is a fiver for both ways.

I'm still going Sawley tomorrow for running in because canal there looks like the least hassle spot for first timer.


I found a thread from 2020 by you lot about my stretch of the Trent:

https://www.rib.net/forum/f50/launch...tts-83587.html

Cheers all, I'll let you know how I get on.

EDIT: just saw on gov.uk water level at Farndon is at 0.5m. Dunno if that's normal.

[ShinyShoe]

Originally Posted by Croolis

EDIT: just saw on gov.uk water level at Farndon is at 0.5m. Dunno if that's normal.

Doesn't look unusual:

https://riverlevels.uk/river-trent-farndon-farndon-river-trent

[Tommy c]

My last grp outfit was a Shetland 535 suntrip.
I remember my mariner 40 6e9 cutting out and relying on a mariner 2.5 2t direct drive . I made 2.5 knots (according to the chart plotter) against a neap in Morecambe bay