Would a 7.5HP be enough for a 10-11' ?

merc20076

Petty Officer 2nd Class
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Sep 9, 2009
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I have 2 7,5 HP Johnson + 1 6HP Evinrude that I work on to fix them (minors repairs) and if I can't get a good price for them to help me buy a 15 HP, I would keep one 7.5HP.

Would a 7.5 HP be strong enough to get a 10-11' out of water with 1 person or 2 max?

Still haven't buy my inflatable yet, probably a zoom or a mercury or a used hypalon. It's pretty sure I'll get a 10 or 11'. Also, arround what speed I could reach possibly with these 7.5 HP. I know that a 15 HP would make them fly.
 

jrs_diesel

Chief Petty Officer
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Mar 3, 2010
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Re: Would a 7.5HP be enough for a 10-11' ?

I have a 9 ft with a 6HP, and that gets 2 people up on plane just fine.

I would think a 7.5 would work, though the 15 would work much better.
 

dingdongs

Chief Petty Officer
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May 29, 2009
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Re: Would a 7.5HP be enough for a 10-11' ?

i have one of the chinese 3.3 meter inflatables which are for a 15hp lump with an inflatable v floor and an ally strong and heavy 4 piece clip together floor.i have tried it with a mercury 5hp motor and will get me on the plane to about 10mph+ or there abouts and it will get me the missus and 3 kids mobile at a much less speed but not on the plane at about 4 mph thats a combined weight of about 200 kg us lot +the 75 kg of boat and the engines weight of about 20kg +fuel for an excursion up the fjord in sweden.i also have a 2010 mariner 15hp and that flies to about 25mph and is a lot of fun.a rib may be a little better and faster but its well good enough for me and can be assembled in about 30 minutes out of the bag and on the water.similar to this and you may have them on the other side of the pond somewhere http://cgi.ebay.co.uk/New-4-5-Man-3...ng_Goods_Sailing_Boats_ET&hash=item35ae8f50c1 .anyhow your 7.5 hp should be adequate so long as your not too far from land with the older lump.
 

merc20076

Petty Officer 2nd Class
Joined
Sep 9, 2009
Messages
156
Re: Would a 7.5HP be enough for a 10-11' ?

No.............

Ok, I forgot to mentioned that I don't weight 300 pounds (205 to be exact) and I go fishing very often alone and a lot of trolling too.

I had a 2 HP Evinrude and on a 14' fiberglass I reached 8-9 mph with the smallest prop.

I would eventually get a 15 HP.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Re: Would a 7.5HP be enough for a 10-11' ?

i have one of the chinese 3.3 meter inflatables which are for a 15hp lump with an inflatable v floor, also have a 2010 mariner 15hp and that flies to about 25mph .

It's mission impossible to achieve 25 MPH on a 3.3 mtrs sib with 15 HP, a 380 well inflated with 18 HP gets 22 MPH (flat calm waters) so bit less 20 MPH would sound proper.

Happy Boating
 

jrs_diesel

Chief Petty Officer
Joined
Mar 3, 2010
Messages
552
Re: Would a 7.5HP be enough for a 10-11' ?

I don't know, I got 7-8 kts (8-9.2 MPH) out of a 3.5 HP Nissan with my 9 ft SIB. Used my handheld GPS to get the speed.
 

lepar5

Recruit
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Apr 9, 2010
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Re: Would a 7.5HP be enough for a 10-11' ?

It can be enough if you are alone and limit for 2.
I have a 11'2'' zodiac with inflatable hi pressure floor and i can plane with a
8 hp tohatsu 2 stroke, When we are 2, i change the prop. with 1 inch less pitch and it's ok.
 

mikethepike

Seaman Apprentice
Joined
Dec 15, 2010
Messages
42
Re: Would a 7.5HP be enough for a 10-11' ?

I have 2 7,5 HP Johnson + 1 6HP Evinrude that I work on to fix them (minors repairs) and if I can't get a good price for them to help me buy a 15 HP, I would keep one 7.5HP.

Would a 7.5 HP be strong enough to get a 10-11' out of water with 1 person or 2 max?

Still haven't buy my inflatable yet, probably a zoom or a mercury or a used hypalon. It's pretty sure I'll get a 10 or 11'. Also, arround what speed I could reach possibly with these 7.5 HP. I know that a 15 HP would make them fly.

The 7.5hp might get you out of the water by yourself....but it will labor all day to push you. You might get 13-17mph out of it ....if you get it on plane

I have the 10'2" Zodiac zoom with a 15hp 4stroke mercury ...and this does 28mph with me in it and i weigh 240lbs!!! I can get me and 2 120lbs girls on plane with this motor. Go big and it will last longer
 

merc20076

Petty Officer 2nd Class
Joined
Sep 9, 2009
Messages
156
Re: Would a 7.5HP be enough for a 10-11' ?

The 7.5hp might get you out of the water by yourself....but it will labor all day to push you. You might get 13-17mph out of it ....if you get it on plane

I have the 10'2" Zodiac zoom with a 15hp 4stroke mercury ...and this does 28mph with me in it and i weigh 240lbs!!! I can get me and 2 120lbs girls on plane with this motor. Go big and it will last longer



This is one inflatable that I look a lot to buy! How is it? Have heard good and less good about it.

For the 7.5 HP, i'll be enough start with untill I find a good 15 HP and sold those O/B. For speed, my boat does 30-31 MPH with a good classic Evinrude 40 HP!
 

Howard Sterndrive

Rear Admiral
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Nov 5, 2008
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4,603
Re: Would a 7.5HP be enough for a 10-11' ?

Would a 7.5 HP be strong enough to get a 10-11' out of water with 1 person or 2 max?
if the 7.5 is well tuned and in good shape with the right prop, it will plane with 1 person (but barely) 12- 15 mph tops
not a chance of planing it with 2 people
 

mikethepike

Seaman Apprentice
Joined
Dec 15, 2010
Messages
42
Re: Would a 7.5HP be enough for a 10-11' ?

We have in Mi a boat club that sponsors a "dinghy thinghy" in the summer where we stop off at dfferent sea-side localities (canal boat club members houses ) where they celebrate good stewardship +libations!! Here is me in the captains hat and my "CREW"@ our next stop--The Boat club
 

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mikethepike

Seaman Apprentice
Joined
Dec 15, 2010
Messages
42
Re: Would a 7.5HP be enough for a 10-11' ?

if the 7.5 is well tuned and in good shape with the right prop, it will plane with 1 person (but barely) 12- 15 mph tops
not a chance of planing it with 2 people

The 7.5 will plane you ...and that is it. Like i said b4, the 15 will take a fat guy and 2 hot chicks to your LZ. The 9.9 + 15 4stroke are the identical same engine ( from 04 -08 or 09 ) except the carburation is different ..the jets are bigger and some other smallr mods...but side by side the 15 will walk away from the 9.9 all day. Me by myself can do 28-31mph and the engine doesnt labor
 
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