Twin or single - opinions please

[Dunaruna]

My wife and I have an opportunity to but a 45ft houseboat, the pontoons (steel rusted) and motor (died) need replacing but the structure is modern & solid, its an bargain at $5000.00. I estimate about $6000.00 for new pontoons. I need to factor the cost of a single or twin drive set up.<br /><br />I'm a 4stroke outboard virgin so any advise would be appreciated.<br /><br />Do I go with:<br /><br />1 motor, maybe 90hp or two smaller motors, maybe 30 or 40 hp. Speed is not a concern, economy is.<br /><br /><br />It will be used on a large freshwater lake. This lake sometimes gets blowy so twin outboards (set on the pontoons) would make handling easier. Am I overthinking this?<br /><br />Any comments please.<br /><br />Aldo

 

[plasticfailure]

Re: Twin or single - opinions please

my parents have an older pontoon boatel housboat, 48' i think. it has an old 2 stroke 70 hp. Goes about 3 mph cruising, 4200 rpm. The newer and bigger houseboats where we keep it have two 70's, (i think they used 70's just because then all the houseboats had the same motor, but twin 30's should be fine for a 45 footer) one on each pontoon. If you can mount the motors on the pontoons, you have much better control for docking. If you can do that I would, in strong winds docking is a pain. I don't know what the difference would be for fuel economy. <br /><br />With just the single engine in the middle we've had trouble getting off the dock when the wind is just right. Two motors is definately the way to go for handling.

 

[Dunaruna]

Re: Twin or single - opinions please

I'm thinking the same in regard to handling. Last year we hired a 35fter with twin 9.9hp. Sound crappy but it was surprisingly manuverable. Just didn't cruise to well .<br /><br />I'm thinking twin 30's. Would like to know rough fuel consumption figures compared to one 90hp for instance. It will also be 12volt only, no generator (can't stand the noise at night). Two motors mean two alternators.<br /><br />Aldo

 

[BillP]

Re: Twin or single - opinions please

VERY simple. No matter what the final HP is hanging on the transom...<br /><br />Economy dictates a single. Safety and manueverability says twins at higher weight, purchase and maintenance cost. <br /><br />The real question is what HP and what brand? Maybe one big main motor and a smaller kicker for emergencies...the smaller motor would at least give steerage to a shore. Maybe a 14' skiff and motor to double up as tender and safety backup would work.

 

[Dhadley]

Re: Twin or single - opinions please

On a houseboat like that the only time I'd consider twins is if there isnt room for 3.

 

[phatmanmike]

Re: Twin or single - opinions please

houbout a larger 70hp or so in the middle, and two smaller, maybe 9.9 or 15 on each tube, that would make you the talk of the town, and then youd have 3 alternators and props

 

[DJ]

Re: Twin or single - opinions please

Twins are almost mandatory for any type of manueverability. Trying to swing an object with that kind of surface area is difficult at best.<br /><br />Make sure you get engines with gearcases designed for heavy use. I would recommend one of Mercury's Big foot models. Make sure it is propped for heavy loads.

 

[Dunaruna]

Re: Twin or single - opinions please

The marina at this lake has 300 houseboats. Big mixture of drives used, twin & single outboards, twin & single I/O, gas & diesel. Man it get confusing.<br /><br />Phatman & Dhadley, I think 3 motors would explode the bank balance, nice thought though .<br /><br />I think two bigfoot mercs are in my future.<br /><br />Thanks guys.<br /><br />Aldo

 

[BillP]

Re: Twin or single - opinions please

50 hp will certainly push a 45' pontoon boat in calm water. Windage is your enemy and can be calulated by using wind presure at speed against the calculated thrust of the engine. It isn't perfect but is way more accurate than guessing. It is also handy for anchor calcs. Here's a few lbs per sq ft pressure numbers. Reference the Beaufort scale.<br /><br />Notice that the pressure at 78.1 kts is 128 times more than the pressure is at 6.9 kts. Yet 78.1 kts is only 11 times stronger wind.<br /><br />Windspeed in Knots = Pounds Sq Ft of Wind Pressure<br />6.9 = .23<br />11.3 = .62<br />15.6 = 1.20<br />20 = 1.90 <br />24.3 = 2.90<br />29.5 = 4.20<br />34.7 = 5.90<br />41.6 = 8.40<br />48.1 = 11.50<br />56.4 = 15.50<br />65.1 = 20.60<br />78.1 = 29.60

 

[Dunaruna]

Re: Twin or single - opinions please

Thanks BillP, very handy scale.<br /><br />I have boated on this lake for the better part of 25 years. As it is located in a very mountainous region it rarely blows bad but when it does - look out! Most houseboats (the smart ones ) tie up before the storm (no anchoring - way to deep), there are literally thousands of sheltered & secluded coves. My main concern is handling in mild wind conditions. <br /><br />Thanks again.<br /><br />Aldo

 

[Paul Moir]

Re: Twin or single - opinions please

Just wanted to point out a typeo - I'm sure BillP ment Pounds per Sq Foot.<br /><br />Hmm, 30knt wind on me (mabey 5sq ft) would be 1.5 tons of force. I'de be bl.....

 

[BillP]

Re: Twin or single - opinions please

Thanks Paul, good catch...Yes it is POUNDS PER SQUARE FOOT. I edited the bogus info.<br /><br />Bill