Swallow Yachts Association
Swallow Yachts Forum => Technical => Topic started by: David Hudson on 18 Aug 2014, 21:24
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Engine threads are many and various, so let me cut straight to the chase.
While I am sure you could water ski behind a BayRaider powered by a Mariner / Mercury 5 hp engine, is the 3.5 hp version man enough for use as a coastal auxiliary engine?
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A simple answer would be "yes" but in practice I don't think there is a right/wrong or yes/no answer to this - it depends on your sailing area and personal preferences. On the one hand a 3.5hp is easily man enough to propel a BR20 in most conditions, e.g. punching in to a F5 or a few knots of tide. But many chose a more powerful engine for the reassurance that it could more easily cover longer coastal journeys or push you through strong tides if, say, you get caught on the wrong side of your harbour entrance and are fighting a strong ebb. So a 3.5hp will do the job but whether you choose that or a more powerful engine comes down to your preferences for size & weight versus certainty that you have the power no matter what scrapes you get in to.
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Hi Stuart
4hp seems to the neat option for me. Presumably we are talking long shaft?
The Mariner/Mercury has its gear lever on the front panel v. the Yamaha with gear lever on the side. This is the feature that I am pondering. And of course there is the overall value judgement of built quality v price.
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I have now found a thread from August last year.
Would it be possible to put a search function on the Forum?
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A ear lever on the front would be much better than one to the side. Much easier to control your speed in tricky situations in marinas, anchorages etc. I used a 2.3HP Honda on my BC20 initially. Generally it was fine, but as mentioned it was getting in through harbour ebb tides that was a challenge. The other big problem was the lack of a reverse gear. So I upgraded to a Tohatsu. The 4, 5 and 6HP are essentially the same engine, so I went for the 6 for the extra oomph. It must be the largest engine that will fit in the well. I have been very pleased with it, although it is not a great warm starter.
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David ..
You asked the question 'presumably long shaft' - I would recommend short (or standard shaft it is now called).
The main points have been ably answered by others, and my personal opinion is that I would not go to sea without a decent powerful engine, in the range of 4 - 5 hp (four stroke is pretty well what we are stuck with these days) - with a reverse gear.
The front gear lever is very useful - though a lot of manufacturers use the side lever as they are easier to connect upt o morse controls or similar.
I use a Tohatsu 5 on my BR - it may be useful to look for a specified sail drive prop, but I'm not sure if they come on o/b's that small.
Andy
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David,
You can search in one of two ways:
1. On the right end of the black menu bar there is a lighter grey section that contains an image of a magnifying glass. Click on that and the box will expand. Enter your search criteria and press Enter to search. That searches all of the forum and website.
2. The forum's menu bar (the blue one below the black menu bar) contains a Search link. Click on that to search just the forum.
Julian and Andy have summed it up well. I use a 2.5hp Suzuki for my coastal cruising and really rate the engine - very light, economical, pushes a BRe at 4 knots and starts first time. But if I was doing longer more exposed cruises or sailed in Poole Harbour like Julian and wanted the security of being able to punch against a string tide in the harbour enrance then I suspect would get a bigger motor. Most manufacturers' 4hp, 5hp and 6hp engines seem to be the same model with the 4hp and 5hp versions de-tuned. Given that in the EU at least we can only buy 4 stroke engines in these sizes and hence they are bulky units you may as well go for a larger model.
Incidentally, I liked the simplicity and lightweight nature of 2 stroke engines and felt indignant when these were banned. However, having seen that 5 mins of flushing my 4 stroke OB in a bin leaves the water clear whereas my 2 stroke (one of the last produced, so 1:100 mix, etc) turned the water milky I am now pleased to be using a 4 stroke.
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Hi David,
I have tried several. Although a 2.5 HP will do most of the time you can easily get into trouble if you need to reverse and have to turn the engine around. Go for an engine with forward and reverse gears. You will be surprised how often you use the reverse. As for power of the engine I have a yamaha 4HP. I chose this because there can be times when you are stemming a fierce tide or current, the wind is strong on the nose, it is raining, the crew are fed up and you want to get home. I have needed it twice this summer; trying to get into Burnham Overy Staithe harbour entrance with the full tide surging out was a challenge and we only succeeded by hugging the shore out of the tide as much as possible and then trying to get into Chichester harbour entrance against the tide. I bought a new Yahama 4HP 4 stroke at the boat show last January because my 2 stroke 4HP had a habit of dying when it was at low revs and then not starting. It would also jump out of the water when put in reverse. My new engine starts easily when cold - three or four pulls and first time when warm.
I bought the engine with an "alternator" they call it something else - a lighting coil I think. Some of our friends said this would not help but actually it has proved terrific. I bought it because with my Garmin 556S the battery would die after about two days moderate sailing and always just when we needed to see the depth etc. I have a COMFORT INDICATOR EYELET M6, which has green orange and red flashing lights to give some idea of how much charge is in the battery. Now the motor seems to keep it charged (green light on), at least enough to keep the garmin going and when the Garmin did stop when we had been sailing a lot. just firing up the motor was enough to get the light showing green and the garmin going again. So for me this has been a great help
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Hi David
I'm sure that 4hp engines are twice as good as 2hp. But they will also be twice the weight. I struggle to keep my BR-plus-paraphernalia on (unbraked) trailer weight to less than 750kg. As it is, I have to shove boat stuff in the car boot.
John
(Amongst efforts to keep weight down, I'm presently rearranging my lighting board to fit on the transom - so that I can dispense with those heavy, extending arms on the CLH trailer. But doing so will mean that the distance the boat overhangs the trailer will increase. And that has legal implications.
Surely this isn't what Ratty had in mind. Ho hum.)
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John,
Those trailer arms weigh approx. 8kgs and I removed mine to save weight but also because I didn't like the lighting board being so low. Others have had made stainless steel lighting board mounts that attach to the rudder mount. Rather than craft such an elegant solution I combined a Heath Robinson and bodging approach and use suction dent pullers to attached the lighting board to the aft deck. See attached pics. It works (stress tested on recent 3 hour drive to Cornwall) but is not a solution I am proud of!
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Impressive solution to the trailer board problem - but watch your load overhang on the trailer. The heavy "extensions" count as part of the trailer, making the back of the trailer the end of the extensions. Without them, I suspect that your load (eg the boat) overhangs the back of the trailer more than the legal amount. Somewhere in the postings there's a discussion on the subject.
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The details of overhangs can be found in the thread "Technical - Trailer lighting board" (obvious, really!!)
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Am I correct that a short shaft engine is the requirement on a BR Expedition? I don't want to make an expensive mistake.
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A BRe (and open BR) definitely requires a standard/short shaft outboard and not a long shaft.
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Many thanks for the comprehensive replies.
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Thanks too, Jonathan and Rob, for trailer advice.
John
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Jonathan, with reference to the "Search" advice in your post of 19 August, could this be repeated somewhere at the top of the Forum index page, so that it's accessible and we don't have to remember that it's buried in "The Correct Engine"? I think (Hope) this would be generally appreciated.
Michael
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Done! I have created a "sticky" topic about searching in the General area (sticky means it will stay at the top of the forum and newer topics can't move ahead of it).
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I use a Tohatsu 5 on my BR - it may be useful to look for a specified sail drive prop, but I'm not sure if they come on o/b's that small.
The sail drive prop only comes as standard with a long shaft motor - no good for an SB outboard well. However I bought my short shaft 6hp Tohatsu with the sail drive prop fitted as an extra (which cost mega-extra... but at least I now have a spare propeller). How much difference the different prop makes I've no idea but the motor certainly pushes my BC20 along very well.
The mistake I made was buying the version with an internal fuel tank. I never use it and the filler cap and it's air vent closure simply serve to foul the control line of my Tiller Tamer plus any other ropes that come that way. Another time I'd just have the external tank version.
Peter
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Vagabond sports a 6hp Mercury (Freddie). When first installed Freddie had a standard power boat prop which was changed to a sail drive after the first year. It's made the speed of Vagabond more controllable at low revs and seems to have improved the "miles per litre" on the cruise by about 10 - 15% with (as far as I can tell) no impact on top speed in calm conditions (about 5.5 knots through the water). I can't say that I've noticed any difference in noise level - "loud" in all cases!
Rob J
By the way, the Swallow Boats stand at the Southampton Boat show today was an owners convention! I think we had more owners that potential customers.
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Hi All, old thread but still pertinent, at least to me! I have a 2hp Honda and love it. Always starts on first or second pull. Trouble is that it does not have neutral or reverse. I posted that I had not had any issue with the no reverse. Turning the engine was always OK! I guess I should have waited until I had to maneuver in a tight marina in windy conditions before I spoke. (Lets just say it was more fun for the spectators than for me and I am sure there is a you tube video of it somewhere!).
I am now the proud owner of a 6hp Tohatsu - That has neutral and reverse! It maneuvers much easier. The real reason for the purchase was that I was caught out a couple of weeks ago, about 2 miles off shore on the Pacific with a "Santa Ana" wind condition, on the nose, about 25-30 miles per hour. If not being able to furl the jib completely and have it flog the whole way in was not bad enough, it seemed that there were times I was actually going backwards, being blown out to sea, with my little 2hp working just as hard as it could to get me home! Yes I made it back after a tense motor back in. The old motor was working as hard as it could - Got to love it - But was really on the limit! I had to fill the internal tank up on the way in also.. Did I mention that the waves were also fun with this wind? OK, so in case I ever get into that situation again, I now have the motor to get me out of a tense situation. I am glad I did not have to go to "plan B" and divert to a different harbor as that would have been just too much!
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I really don't agree with the "one size fits all" philosophy that used to be broadcast in the early days of this forum. If you are racing and only need your engine or motor for occasional use, it should be something small and lightweight. If you are also cruising and regularly dealing with long distances and strong winds and currents, you need something altogether bigger and punchier, otherwise you risk getting caught out. If you both race and cruise, then you probably need one of each. If you can only afford one, then safety says that it should be the big one.
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Hi Graham, I second, by my experience above, your opinion that - "If you can only afford one engine, then safety says that it should be the big one".
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Is there much of a difference between the needs of a Br 20 and the Br20exp when it comes to engines? It could be - but I don't see why.
My experiences with "Four Sisters" a Cardigan Bay Lugger (Storm 19 with a lid) and "Wabi" my Deben Lugger Hybrid (a prototype lug and mizzen with a heavy layup and big mainsail) lead me to wonder.
I have a 3hp Mariner twostroke and 4hp Yamaha fourstroke. Huge difference in weight and convenience but not much in performance, you might think. However, against head winds with short steep seas "Four Sisters", elegant creature that she is, rises to each wave, doesn't ship a drop of spray but really needs the extra grunt of the 4 horse if she is to make any progress. "Wabi", on the other hand, smashes through the mucky stuff without a care in the world, joyfully soaking everyone in sight with spray in the process but easily reaching hull speed (7 knots or so) at two thirds throttle with just the little 2 stroke. Very odd.
Perhaps, at the next Swallow Boat Fest, BayRaider and BREx owners could do a few engine swaps to see if there is any significant difference between these two very similar hulls?
....Or, Just for a laugh, arrange a series of Tug-of-War contests between differently engined boats. (My money's on the 6hp Yamahas!)
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Further to Tony's post, I've heard it suggested that filling the ballast tank helps the engine on a BR20/BRe to propel the boat through a short chop. Something to do with momentum being provided by the extra weight, a different underwater profile and maybe a tiny amount less windage. So without ballast, the boat is more like 'Four Sisters' and with ballast more like 'Wabi'. Has anyone tried experimenting with this?
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Hi, Graham.
Definitely, the more mass the greater the momentum.
Sailing "Four Sisters" without her 90kg of lead ballast is fine - on flat water and sensible winds - but at sea, the ballast really does help her go to windward against a chop. The same when motoring. A good slap from a wave stops her dead without the ballast. You have to wriggle through the waves to make progress.
Variable ballast on the BayRaiders/Cruisers is a great advantage, which ever engine you decide on.
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Motoring through a chop (or waves in general), I think more mass and hence more momentum is always an advantage. Apart from the factors mentioned, if you are bucking over the waves rather than cutting through them there's the chance the propeller comes near enough to the surface to entrain air and loose thrust. Admittedly that is more of a problem with a transom hung outboard (where the propeller might even break the surface) but air entrainment is still a possibility since we use short shaft outboards because of the outboard well geometry.
Using the Torqeedo I used to empty the ballast tanks when going against the current in the river (where the waves are very small or absent). Whether having less boat in the water made a significant difference, I've no idea. With the 6hp Tohatsu I've got power to spare so don't bother.
Peter
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Getting a bit off topic now but ...
Wot I don't unnerstand is.. surely the surface level of the water in the ballast tanks lay at the same level as the surrounding water? And therefore has no weight?
The ballast therefore only comes into play when the boat is heeled and the ballast (water) is lifted clear of the surrounding water, it's weight then comes into play and it tries to maintain equilibrium and keep the boat upright.
A container of water submersed in a tub will only weigh the weight of the container - only when you lift it out will you feel the weight of the water plus the container?
Get rid of the water (ballast) and we are left with just the weight of the container (boat) which, of course, is what makes our boats such perfect trailer sailers.
My thinking is therefore - and my own experience seems to support this - that the boat sails (or motors, or rows) as well, if not better, with the ballast tanks full. Of course there is the effort required to get the weight of the water ballast moving in the first place - but if there is no weight, then the effort to move it must be minimal? Unlike conventionally ballasted boats, where the ballast is heavier (denser?) than the surrounding water and takes a lot more effort to get it moving?
Now I am confusing even myself! There must be better minds out there than me who can explain the physics behind water ballast?
I recall sailing with Jonathan on Caledonia last year in my old BR20 with empty tanks, the (notorious) short steep chop on Loch Ness was hitting us on the bow just as we were tacking, the weight of the waves kept knocking us back into stays - I am convinced this would not have happened if we had the weight (but not weight!?) of water ballast to give momentum to carry us through the tack. Indeed, in the recent discussion about raising the main underway, single handed, I always would maintain having the tanks full to give the boat momentum to carry the bow through waves intent on knocking it off your hoped for course.
Maybe worth a library article if someone can explain in words of one syllable the physics behind water ballast!
Andy
Baycruiser23 No.25 'Equinox'
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I think momentum and inertia are what are what affect your sailing.
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Surely once water is taken on as ballast, the adage that water finds its own level does not apply. That is why cargo ships take on ballast to aid stability and the ship settles lower in the water.
If is Friday 13, not a good day to stick my head above the Parapet?
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Hi Andy,
You are confusing mass and weight, and buoyancy comes into this too! Momentum, and the force needed to accelerate or decelerate a body depends on it's mass, not it's weight. Mass is the amount of stuff, in our case the boat, gear, water in tanks, etc. The mass remains constant whether the boat is in the water or on it's trailer (unless you've drained the tank!). The scientific definition of weight is a measure of the gravitational force on the boat. On the moon your boat would weigh much less than on the earth because the moon's gravity is less, although it would still have the same mass. Non-scientifically, here on earth we tend to define weight as, say, the reading of a spring balance. Using that definition, if you put your boat in water it doesn't weigh anything whether the ballast tanks are full or empty. But adding water to the ballast tanks has increased the total mass of the boat.
Filling the ballast tanks makes the boat sink lower in the water because before you filled them they were full of air and adding to the boats buoyancy. Filling the tanks will tend to lower the centre of mass of the boat compared to the centre of buoyancy. Thus the boat becomes more stable when tilted, whether or not the water in the tanks is lifted above the level of the surrounding water. When you accelerate the boat (using either sails or motor) you have to apply more force when the tanks are full because you have to accelerate the mass of water in the tanks as well as the rest of the boat. Similarly when you plough into a wave and it tries to stop you, the same force of wave will have less effect if the tanks are full (because of the extra mass of water) than when they are empty.
Hope that makes sense?
Peter
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Hi Peter,
Great explanation. Simple and clear, need to have that to hand at the next boat show!
Cheers,
Nick.
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"Archimedes' principle", innit?
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Thanks Nick...
however thinking about it, my introduction of the concept of the net weight (as measured by a spring balance) may cause some confusion with regard to how stability works, to try to correct that...
Even when it's in the water the boat has weight, but that weight is exactly cancelled by the buoyancy force. So the spring balance registers zero. That buoyancy force is created by the boat displacing it's own weight of sea or lake water which indeed is "Archimedes Principle" as David says. The buoyancy force is always equal to the weight of the boat because if it is less, the boat sinks lower until enough water has been displaced for the buoyancy to counteract the weight.
The weight acts through the centre of mass (also known as the centre of gravity) and the buoyancy force acts through the centre of buoyancy which is located at the central point of the part of the hull's volume that is under water. People often don't realise that, apart from sailing yachts with heavily ballasted keels, the centre of mass is normally higher than the centre of buoyancy. That is particularly true for large ships where there is a lot more above the water line than below it (as we saw with that car transporter which ended up on the Brambles bank). Ships only remain upright as long as you don't tilt them too much; beyond a certain point there is no return!
What matters for stability is how the centre of buoyancy moves in relation to the centre of mass. I really need to draw some diagrams to illustrate this. When the boat is upright the two centres are directly in a vertical line. As the boat heels the centre of buoyancy moves outwards towards the downward side of the boat. Provided the ballast (including the crew) does not move across the boat, the centre of mass stays in the same place in relation to the rest of the boat. However if the centre of mass is higher than the centre of buoyancy, the heeling of the boat will also move the centre of mass further across towards the downward side of the hull. Imagine a boat where the centre of mass is some way up the mast - in that case it's obvious that it will moves outwards as the boat heels.
For stability it is important that during the heel the centre of buoyancy moves out faster than the centre of mass. This is achieved by keeping the centre of mass as low as possible (and the boat as beamy as possible). As long as the centre of buoyancy is further out, the two forces, of gravity and of buoyancy, act to rotate the boat back into an upright position.
The actual force of this righting tendency depends (as you might expect) on how great the distance is between gravity pulling down and buoyancy pushing up. The way this changes with the angle of heel is what is shown in a "gz" curve where the g is gravity and z is the distance. But for a given distance (that is a for given value of gz), it also depends on how big those two forces are, and that depends on how heavy the boat is. According to Matt's Water Craft magazine article ("What's the point of Water Ballast?", Water Craft 109, 30-33, Jan/Feb 2015) the water ballast in a Bay Raider increases the gz by about 30% (by lowering the centre of mass). But the tendency for the boat to come upright is more than doubled mainly due to the extra weight of the ballasted hull (pulling downwards) and hence the larger buoyancy force (pushing upwards).
If you add ballast to a boat in the form of a closed heavy box of a certain weight, it doesn't matter whether what's in the box is water or lead (provided neither the water or lead can move around in the box). The advantage of lead is you can use a smaller box and you can get it lower down in the hull. The advantage of water is you can add it or remove it more easily.
...wow! I only meant to write a sentence or two! If it's thought worthwhile I could take up Andy's challenge and create a library article with some diagrams. Matt covered much of this in his Water Craft article, although, I imagine to avoid confusion given limited space, he didn't introduce the concept of "centre of buoyancy".
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I for one would welcome a Library article, with diagrams, Peter, but already this bear of very little mathematical brain feels better informed. Thank you.
A small correction if I may - the Water Craft article was by Nick Newland, Matt's father and a naval architect by training. I think he had to do with warship design before small boats took him over. He held my hand, metaphorically speaking, through my first Swallow Boats kit build.
Michael
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Wow! Thanks for such a detailed reply Peter - and a big thank you for that, and for your impending library article with some diagrams? You'll have to do it now! It will be worth the half pint of shandy I buy you next time we meet up in way of apology for making that suggestion.
I clearly have little understanding of what is going on all around me as I happily sail along - all those forces coming into play all around me as I sit ignorantly picking my nose and wondering when the next cup of tea will be.
That'll teach me to idly day dream away all those physics lessons back in the 60's ....
Thanks
Andy
Baycruiser23 No.25 'Equinox'
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What I like and will find useful is the relationship between COG and COB, because when you think of stability in these terms, then it is very clear why internal ballast works, and then the benefits of that being water as opposed to lead (for the dayboat, small yacht) follow neatly.
It is difficult to get this over concisely when chatting to potential converts....in a way that will be meaningful for them and help rather than confuse the process of becoming an owner! At times you see the water ballast feature switch people off, because it is unfamiliar and maybe an unnecessary complication for some.
Cheers,
Nick.
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Back in the early 80's, the "Mini Transat" boats pumped water ballast athwartships to aid righting moments.
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Back in the early 80's, the "Mini Transat" boats pumped water ballast athwartships to aid righting moments.
Yes and so do enclosed car transporters and other ships - pumped systems can be embarrassing if they go wrong (photo attached)!!!
A small correction if I may - the Water Craft article was by Nick Newland
Michael
Thanks, Michael, I'd missed reading the byline under the photo and assumed it was by Matt (though I wondered how he found the time to write it!), I'll correct the attribution in the Library version.
Peter
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In case it is of interest - the new Volvo Ocean 65s have three venturi filled water ballast tanks. Two aft 800L tanks under the cockpit sides and one 1000L tank forward of the mast. There is very little information on how the tanks are utilised - as these are one of the variables in these new 1 design boats. However, I have seen two references to the forward tank (new to the 65s) as having been added to make the boats less twitchy and to improve upwind performance and reduce the bow falling off to leeward in big seas.
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I should have added that the water ballast augments a canting fin keel (overall draft 4.7m) with a 3465kg bulb!
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In case it is of interest - the new Volvo Ocean 65s have three venturi filled water ballast tanks. Two aft 800L tanks under the cockpit sides and one 1000L tank forward of the mast....... references to the forward tank (new to the 65s) as having been added to make the boats less twitchy and to improve upwind performance and reduce the bow falling off to leeward in big seas.
Of course I don't actually know why those particular tanks have been added, but what they will do when full is increase the moment of inertia of the hull. Moment of inertia is the resistance to a rotational force. In other words the boat will indeed be less "twitchy". Note though that it's not just the forward tank that will contribute to that effect.
That has reminded me of two separate conversations with Matt. In one I mentioned that a heavier boat might be desirable when beating through head seas and Matt responded that a lighter boat should always be faster. However when I was discussing permanently installing some gear right up in the pointy bit of the "V-berth" area (for want of a technical term), Matt's response was that a bit of mass there might be a benefit. Matt's two responses are not necessarily contradictory if what helps you punch through the waves is moment of inertia rather than momentum. Yet more to think about!
Peter
p.s. if Seatern had that fin keel I would be constrained to sailing in water less than 4.7m deep!
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I have just about caught up with the intellectual content of recent post on this thread. I usually coast along in glib mode, often offending people on the way. I have now moved up a gear or two and hope my contribution is relevant.
Those who were involved in the 1980, 5o5 World Championships off Hayling Island may remember Steve Benjamin. Steve, from the States, was crowned World Champion that year.
He had less luck while preparing his new Lindsay dinghy for the Australian Worlds in '76. He spent time trying to eliminate the fore and aft pitching moments in his boat, assessing the effect of water taken onboard by the spinnaker chute. This involved placing more and more 6 packs of Miller beer on the dinghy's bow. This led to his crew installing turtles for the spinnaker. Further detail escapes me but I expect the Miller went the way of all beer. Carbon masts were a long way off at that time.
Unfortunately the dinghy did not make Worlds. My helmsman had to tell him that his boat had been destroyed by a loose container while at sea.
There, almost relevant.
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In the past I've advocated the little Suzuki 2.5 for the Bayraider. It's always been powerful enough and it's light.
I'm not so sure anymore. Recently I've been at sea (around Mull) worrying I might run out of fuel. The integral tank is small. Swell and spray have kept me from topping up. Running out of fuel would be awkward or worse.
So I now think for coastal cruising, a bigger motor with its bigger external tank is preferable.
Or is there a way to get around this? Is there a safe way to refill the tank when it's bouncy and wet? Or has anyone successfully linked up an external tank to a little outboard like mine?
John
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John,
As we discussed at Sail Caledonia, I am also in the minority that likes the Suzuki 2.5hp motor - it's light, reliable, economical and has sufficient power for a BR/BRe in all but the strongest headwinds and foul tides. But I share your concern and didn't find a complete solution for this. However, here are my thoughts.
First, while it's always reassuring to know you can't run out of fuel, I've found the motor very economical. For example, we sailed from Weymouth to Poole last summer and the wind failed after just a few miles. Looking back at my log, I see that we travelled 30nm of which at least 25nm must have been pure motoring or wind-assisted motoring. We used 3 litres of fuel, i.e. approx. 2 top-ups, but we didn't have to contend with headwinds, etc. That still required refuelling at sea but I was happy that I could time the refuelling somewhere convenient, i.e. a more sheltered area. I run the motor at no more than half throttle because beyond that gives little extra speed and I suspect burns disproportionately more fuel.
I also use 2 litre "Fuel Friend" fuel tanks (designed for overland motorbike expeditions) which are easier to use at sea and to stow (I put them in Gorilla buckets in the aft buoyancy chamber) than the larger fuel tanks. Here are links to examples of the ones I use:
http://www.ebay.co.uk/itm/Motorcycle-Plastic-Fuel-Can-2L-Black-Fuel-Friend-/291626612770?hash=item43e64cf822:g:vMoAAOSwf-VWWWsM
http://www.ebay.co.uk/itm/Motorcycle-Screw-On-Fuel-Can-Spout-with-Cap-for-Fuel-Friend-1Ltr-1-5-Ltr-2Ltr-/291661835767?hash=item43e8666df7:g:F1IAAOSwGotWm1pG
But you could add an external tank for a better solution. Here are links to YouTube videos that show how to do that:
https://www.youtube.com/watch?v=ZS0sn46-ITQ
https://www.youtube.com/watch?v=nYxJQewMGI0
I started down that road but never completed the work because after my Weymouth to Poole journey and buying the Fuel Friends this became less of a concern for me. But I did buy a fuel cap and attach a fuel tank connector to it - see attached photo. You can have this if you want (let me know and I'll post it to you) although I did find that Suzuki changed the threads on their fuel caps so it may or may not fit your motor (mine's a 2012 model).
From memory, I think those YouTube videos show a fully unattended solution that added a gravity-fed external tank. I was erring to an even simpler solution which was to have an attached tank sited on the cockpit floor that I used to top-up the outboard's tank with a few squeezes of the primer bulb. I have a few spare fuel lines & bulbs in the garage and measured which one pumped the most liquid per squeeze.
I can't remember the amounts being shifted per squeeze, but was happy that it was sufficient. I guess that to complete that solution I just needed to connect a tank to my modified fuel cap and provide a way for air to escape from the outboard's tank when fuel is added. Ideally I would have added a little screw-in air valve to the cap for that but, being lazy, had considered just loosening the cap slightly to allow for this.
This all needs a little more thought but I think there is a solution here. I hope that helps.
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Jonathan
Thanks for that comprehensive reply. Plenty of options for me to think through there.
John