Twin Outboard Equivalent to Single Outboar Engine

[ERR446]

I am in the process of buying a new 21 foot boat which weighs 2300 pounds and has a maximum rating of 200 hp. Have seen test results for the boat I am considering with a 130 hp Honda 4-stroke. I would be satisfied with the performance indicated by this test data but am reluctant to buy a Honda because ther are no nearby dealers in my area. Does any one out there know what hp twin outboards would be equivalent to a single 150 hp engine? There are many factors involved and don't know how to get a handle on the answer.

 

[62_Kiwi]

Re: Twin Outboard Equivalent to Single Outboar Engine

Hi ERR446<br />Since you can't go over 200hp with that boat, you'd probably need to look at twin 90hp. Twin motors introduces extra drag in the water and extra weight, so you'd probably find that combined they'd give similar performance to a single 150hp or possibly even less. Just my 2 cents worth - I've never tried it myself.

 

[Lark40]

Re: Twin Outboard Equivalent to Single Outboar Engine

Go buy a current copy of Trailer Boats.<br /><br />They did an article about trying one large motor and then twins with half the rating.<br /><br />I recall that the twins outperformed the single in just about every respect.<br /><br />That surprised the writers.<br /><br />Check out that article.

 

[araiha]

Re: Twin Outboard Equivalent to Single Outboar Engine

It makes a difference as to the style of the hull. A deeper V boat will require more power to plane. You also need to balance motor weight against what you gain. Find out what the heaviest 200 motor is that you can buy, cut that weight in half and you will know what size twins you 'could' put on the boat. Another consideration is that there needs to be a certain amount of separation between the motors (center to center, about 24 inches, min.). Manufacturers specify this in their rigging guidelines. Another problem with twins in some applications is that the transom space just is not big enough, particularly with 2 v blocks. <br /><br />My boat has two Yamaha C90 motors (in line 3 cyl) which weigh 252 apiece. this is on a 23 ft boat, which has a dry weight (no fuel or gear or motors) of 2500 pounds. This works to push the boat at 25-28 knots on one, other tilted up, and 35-38 knots on both.<br /><br />I chose this because twins are the ultimate in spare parts, though more expensive, can give good legs (running single, which I do a lot), gives better slow maneuverability, and besides... They look cool!

 

[ERR446]

Re: Twin Outboard Equivalent to Single Outboar Engine

Thanks for the inputs. I think I would like to use 4-stroke outboards and have had difficulties with the price and weight of the new 200 and 225 hp 4-stroke pricing. Pricing is the same as a new small automobile! Think if I spend that much it might make sense to look for twins. HP is rated at the shaft and two props provide a lot more thrust because of two prop even when the increased drag is considered. I think that is why the comparison test reported this month in Trailer Boats came out the way it did. Thanks again.

 

[MOTAS]

Re: Twin Outboard Equivalent to Single Outboar Engine

Tie two Honda Civics and get one Mack Truck!!!<br />The 21st century invention from trailer boats.