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06 March 2010, 05:35
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#1
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Member
Country: USA
Town: San Jose
Boat name: the boat
Make: AB Oceanus 15VST
Length: 4m +
Engine: Etec 60
MMSI: 338102309
Join Date: Mar 2010
Posts: 9
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Twin small outboards on inflatable
Has anybody had any experience with small twin outboards on inflatable?
I have 8'8'' inflatable with Honda BF2 2HP outboard. It's not fast. I can barely make about 5 knots with just myself. But I love my outboard. I have an idea of twin mount. It's definitely going to add a redundancy. I'm having quite long trips along the shore from time to time. Rowing 5-10 miles will not be an option. Do you think twin 2HP is going to be twice faster? Is it going to be any faster/slower compared to 4HP outboard?
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06 March 2010, 06:09
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#2
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Member
Country: UK - England
Town: gravesend
Boat name: curach/Earl
Make: seago/Lifeguard 4M
Length: under 3m
Engine: 3.3 marinar/10 hp
Join Date: Jul 2008
Posts: 760
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Quote:
Originally Posted by ifeoktistov
Has anybody had any experience with small twin outboards on inflatable?
I have 8'8'' inflatable with Honda BF2 2HP outboard. It's not fast. I can barely make about 5 knots with just myself. But I love my outboard. I have an idea of twin mount. It's definitely going to add a redundancy. I'm having quite long trips along the shore from time to time. Rowing 5-10 miles will not be an option. Do you think twin 2HP is going to be twice faster? Is it going to be any faster/slower compared to 4HP outboard?
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Seems a small craft to be having twin engines,8'8,with two don t know what the weight would be ?,but if combined to the recommended weight for the transom,well,someone with more experience on here will be able to help you im sure,Happy sibbing
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06 March 2010, 07:25
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#3
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RIBnet supporter
Country: UK - Channel Islands
Town: Alderney
Length: no boat
Join Date: Sep 2006
Posts: 2,870
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Quote:
Originally Posted by ifeoktistov
Do you think twin 2HP is going to be twice faster? Is it going to be any faster/slower compared to 4HP outboard?
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You will probably go slower
Get a lightweight 5 horse perhaps?
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06 March 2010, 15:31
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#4
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Member
Country: USA
Town: San Jose
Boat name: the boat
Make: AB Oceanus 15VST
Length: 4m +
Engine: Etec 60
MMSI: 338102309
Join Date: Mar 2010
Posts: 9
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Quote:
Originally Posted by thornbackflound
Seems a small craft to be having twin engines,8'8,with two don t know what the weight would be ?,but if combined to the recommended weight for the transom,well,someone with more experience on here will be able to help you im sure,Happy sibbing
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The inflatable is rated for up to 5HP, 55lb (25kg). Honda BF2 is 27lb, so it's 54lb total.
Should be OK for transom. I'm just not sure about performance.
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06 March 2010, 16:34
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#5
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Member
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 4,997
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Quote:
Originally Posted by ifeoktistov
It's definitely going to add a redundancy.
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So will a set of oars.
I looked into putting twin 25's on my SIB and its not worth the hassle.
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06 March 2010, 16:41
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#6
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RIBnet supporter
Country: UK - Channel Islands
Town: Alderney
Length: no boat
Join Date: Sep 2006
Posts: 2,870
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Quote:
Originally Posted by chewy
So will a set of oars.
I looked into putting twin 25's on ym SIB and its not worth the hassle.
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I used to be a huge fan of twin engines, but various threads over the years on here have opened my eyes.
If neither performance nor initial cost are an issue then yeah - great. Otherwise not so much.
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06 March 2010, 16:51
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#7
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Member
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 4,997
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A 10hp 2 stroke should make it shift.
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06 March 2010, 23:41
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#8
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Member
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 4,627
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Ignoring the hassle of two throttles, you could probably steer using one engine. However, you won't get twice the speed from two engines. Also, if your single engine reaches maximum revs, as it should, then with a second one you will need to change the props for ones of greater pitch, you may find they aren't available. The wee Honda engines are noisy, I'm not sure I'd want to sit beside two of them at full chat. I used to run two 30hp on a five metre sib, it was a good arrangement.
__________________
JW.
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07 March 2010, 20:38
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#9
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Member
Country: UK - Scotland
Town: Aberdeenshire
Boat name: Sula
Make: Ribcraft 4.8m
Length: 4m +
Engine: Tohatsu 60hp + aux
MMSI: 235087213
Join Date: Jun 2007
Posts: 1,396
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Quote:
Originally Posted by malthouse
You will probably go slower
Get a lightweight 5 horse perhaps?
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I'll second that. Two engines for day-to-day boating is trouble. You have the combined steering and throttle to contend with. Get yourself a light-weight 2-stroke or 4-stroke.
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08 March 2010, 07:24
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#10
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Member
Country: UK - England
Town: Marple
Make: Zodiac
Length: under 3m
Engine: Tohatsu 9.8
Join Date: Jun 2009
Posts: 222
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Engines
If that Honda BF2 engine weighs 27lb you could get a Mercury/Mariner 6hp and that weighs 26lb.
I know you said you wanted to keep your existing engine, but you could use it as a spare....the Mercury 6hp on my 2.8m SIB will achieve 14.5mph and that's with two of us on board.
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