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Old 26 June 2012, 21:25   #1
SR4
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Country: UK - England
Make: Avon Searider
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Is a 50hp 4 stroke worth getting to replace a 2 stroke?

I have a Mercury 50hp 2 stroke 1999, immaculate condition unmarked with low hours, just wondering if it is worth replacing with a 4 stroke (Honda BF50) to get more to the gallon. I'm considering circumnavigating the UK so the saving may pay for it. My circumnavigation of the Uk is just this weeks idea after seeing Cookee go in his boat, seems pretty simple just keep going forward and keep right Thought it would give me something to do for a week, being retired I get bored
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Old 26 June 2012, 21:30   #2
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No no no & no!
If it weighs in more than your 2st I wouldn't as the back end of the SR4 is low as it is!
Lighter the better I would go for.
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Old 26 June 2012, 21:34   #3
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Mine is badged on the side as weighing 103kg, the Honda is 97kg Honda BF50 Outboard Engine - 50 hp boat motor specs and features

The trip would around the coast would be about 5,000 miles so I guess I would need to calculate the saving, the Honda would be about £6k to buy plus fitting and I don't know the value of a secondhand Mercury 50.
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Old 26 June 2012, 21:38   #4
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Depending on what 4 stroke you get it could be stern heavy.
It won't take off as fast.

The saving won't pay for a 'round Britain' if you spend more on a new outboard than the fuel will cost
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Old 26 June 2012, 21:40   #5
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any idea what I get to the gallon with the Mercury, and what to expect from a BF50, I can't calculate without that

If I did say 150 miles ish a day, I could be around in a month, the cost of fuel would be much cheaper than sitting at home buying accessories!
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Old 26 June 2012, 21:44   #6
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Ask Mollers as he has that combo on his SR4 I don't know what my Yam 50hp 2st comes in at about 75kg
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Old 26 June 2012, 21:44   #7
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Country: UK - England
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I'm considering circumnavigating the UK so the saving may pay for it. My circumnavigation of the Uk is just this weeks idea after seeing Cookee go in his boat, seems pretty simple just keep going forward and keep right Thought it would give me something to do for a week, being retired I get bored


when are you thinking of doing this? It is also something that I have been contemplating, being retired and bored also
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Old 26 June 2012, 21:49   #8
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OK, lets make a plan I have all the time in the world as long as my heart is beating, would be fun in a pair..and safer. I have courtesy lights and an orange plotter which might help I am always in the South of France for all of August every year, so any days apart from that lets do it. The furthest I have been is 8,000 miles in a landing craft down through the South Atlantic, so 5,000 hugging a coast should be a piece of cake

P.S. I have only just recently got mine (4mtr Searider) and due to the weather had limited goes in it, I have not really been in a small boat apart from my other tender which is a Zodiac 320 with a 9.8 Tohatsu, I'm used to the luxury and amenities of a larger motor cruiser. I'm heading from Portsmouth to Bembridge this weekend so I will see how that goes, I guess it would be similar.
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Old 27 June 2012, 13:39   #9
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Hi

I have no idea how many litres you would use for this trip but the honda engine would cost £5262.00 inc vat not including anything for your engine.

I have swapped a 1999 mercury 90hp for a new Honda and know the difference between the 2 when pushing a shetland 610 a long weighing around 1400kg give or take 100kg but dont have personal data on 50hp's on a searider sorry.

Dave
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Old 27 June 2012, 13:59   #10
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Ok, not maybe an SR4/50 but with my 1980-ish Merc 60 (premix) on a 5m Humber, if I hover around the 20-23 knot mark I can get 0.8L/ nautical mile. Whiole lot clocks in at 430Kg fuelled.

I got much the same out of a Suz 30 on an SR4 at a similar speed.
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Old 27 June 2012, 14:09   #11
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Sounds like a great adventure.

Broardening it a tad if I may - one day I'd like to get another Searider and it would be a 4m rather than the 4.7m I had previously - just for me and my young son really. Is a 2 stroke 50 the de facto fitment for these (or does a 40 have it's own benefits) and if so what's the typical performance, 1.5 to 2 up, non-flooding hull etc? Would also be interested in the running costs at WOT per hour if anyone has logged this?

Anyone gone from a 4.7 or 5.4 to a 4m Searider?
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Old 27 June 2012, 17:55   #12
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Mine performs really well with my Mercury 40 hp two stroke with power trim .Its very well balanced being a light engine and Ive kept the boat light as i can with alloy a frame and distributing the weight well
If you read through this thread you can see what performance Ive been getting ,all test were with two people and 25 ltrs of fuel and gear on board
My hull is immaculate with no marks and engine is about 1 1/2 " raised


http://www.rib.net/forum/f36/anyone-...rop-48868.html
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Old 27 June 2012, 18:49   #13
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Is your hull dented or is the second roller back just not adjusted properly? Also is that the original colour or have you painted it?
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Old 27 June 2012, 18:57   #14
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Quote:
Originally Posted by Max... View Post
Sounds like a great adventure.

Broardening it a tad if I may - one day I'd like to get another Searider and it would be a 4m rather than the 4.7m I had previously - just for me and my young son really. Is a 2 stroke 50 the de facto fitment for these (or does a 40 have it's own benefits) and if so what's the typical performance, 1.5 to 2 up, non-flooding hull etc? Would also be interested in the running costs at WOT per hour if anyone has logged this?

Anyone gone from a 4.7 or 5.4 to a 4m Searider?
I can do some measurements for you now I have the plotter, as for how many up I guess it depends how muscular you are I weigh in at 135kg with little fat, I guess that could be equal to two skinny people, so will have to calculate using that. I have a 50hp 2 stroke, from what I have encountered it is more than powerful enough for the job, with my new rev counter I should be able to see the most economic revs and speed
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Old 27 June 2012, 19:29   #15
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when you compare the weight of the 40 hp 2 stroke and 40 honda it is around 17 pounds heavier. Not a lot as an overall percentage but it has reminded me to take some of the junk off our boat that the mrs keeps putting on and that its time to start the diet!
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Old 27 June 2012, 19:51   #16
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Quote:
Originally Posted by SR4
any idea what I get to the gallon with the Mercury, and what to expect from a BF50, I can't calculate without that
Some years ago I used every last drop of fuel from 2 x 25l tanks and managed 85 miles on it. This was with a Honda 50 on a 19' Orkney day fisher.
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Old 27 June 2012, 21:31   #17
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Quote:
Originally Posted by SR4 View Post
OK, lets make a plan I have all the time in the world as long as my heart is beating, would be fun in a pair..and safer. I have courtesy lights and an orange plotter which might help I am always in the South of France for all of August every year, so any days apart from that lets do it. The furthest I have been is 8,000 miles in a landing craft down through the South Atlantic, so 5,000 hugging a coast should be a piece of cake

P.S. I have only just recently got mine (4mtr Searider) and due to the weather had limited goes in it, I have not really been in a small boat apart from my other tender which is a Zodiac 320 with a 9.8 Tohatsu, I'm used to the luxury and amenities of a larger motor cruiser. I'm heading from Portsmouth to Bembridge this weekend so I will see how that goes, I guess it would be similar.
It would take some planning to put together, were about are you based/looking to set off from? I am in north wales
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Old 27 June 2012, 21:33   #18
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Portsmouth, so you are just around the corner

There would be no rush, it's pretty straight forward stuff though, just keep land on your right and zoom round
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Old 27 June 2012, 21:35   #19
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there aint many petrol stations up in them there hills in scotland though is there? What about overnight stops etc
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Old 27 June 2012, 21:39   #20
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Ah! got a plan, didn't mention about the back up team, got a fully kitted motorhome to shadow with spares, fuel and plenty of accommodation, maybe get a volunteer to drive it for us
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