Twin outboards

Outboard designs up to 14'

Moderator: ttownshaw

Post Reply
User avatar
Andy Garrett
Posts: 1328
Joined: Tue Aug 31, 2010 11:44 pm
Location: Nampa, Idaho

Twin outboards

Post by Andy Garrett » Thu Feb 28, 2013 11:36 am

Anyone ever consider twin 25s on a Zip or maybe twin 30s on a Malahini before?
Andy Garrett

Perhaps the slowest Zip build in Glen-L history...

pamelalynne1
Posts: 398
Joined: Thu Jul 29, 2010 3:55 pm
Contact:

Re: Twin outboards

Post by pamelalynne1 » Thu Feb 28, 2013 11:56 am

Twin outboards on the Zip or Malahini may not be a good idea. It might necessitate a redesign of the motor well and extensive reinforcement due to the weight of two outboards. One 50 HP does not weigh that much more than a 25 HP. Certain designs, such as catamarans, may give better performance with twins; but I do not see any advantage on the two designs you mentioned. BTW, two outboards cost twice as much to purchase and to operate.
I'm sure some of the Zip and Malahini builders will chime in here.

User avatar
vupilot
Posts: 3481
Joined: Wed Apr 15, 2009 7:36 am
Location: Indy
Contact:

Re: Twin outboards

Post by vupilot » Thu Feb 28, 2013 1:54 pm

One thing you have to keep in mind is that the performance of two 25hp is not going to be equal to one 50hp. Its going to fall somewhere in between in compairable performance. It is cool though and you do gain redundancy but other than that their really is no practical reason to do it other than its just plain fun. Here is a nice old woody with vintage twin mercs.
http://www.youtube.com/watch?v=tmiEIM_qZdo

Retroman
Posts: 199
Joined: Mon Apr 25, 2011 5:08 am
Location: Great South Bay, Long Island, NY. Building a Zip/Flying Saucer

Re: Twin outboards

Post by Retroman » Thu Feb 28, 2013 7:51 pm

Unless you just had a real compulsion to do it, or came across a real good deal on 2 old Mercs (like I did) there would be no good reason to do such a thing. I think about it everyday. Now that your into retroboats and antique outboards, I'm sure it's only a matter of time before you do it. LAUNCH DAY IS FOUR WEEKS AWAY.
RetroMan
Built A Zip/Flying Saucer. I do my boating on South Oyster Bay, Long Island, NY
Documenting my build on YouTube @ http://www.youtube.com/SuperUnknownMC

rjw
Posts: 18
Joined: Thu Jan 03, 2013 2:33 pm
Location: Near Toledo OH

Re: Twin outboards

Post by rjw » Thu Feb 28, 2013 8:33 pm

But could twins add maneuverability, a la twin screw inboards?

I'm looking to do a Waterlodge two houseboat with an 8' beam - and jave been thinking twin outboards might help with maneuvering

pamelalynne1
Posts: 398
Joined: Thu Jul 29, 2010 3:55 pm
Contact:

Re: Twin outboards

Post by pamelalynne1 » Fri Mar 01, 2013 9:40 am

The maneuverability advantage with twin screw will depend on how far separated the two shafts can be placed. In most inboard designs they are separated by nearly half the beam width. This does give an advantage to turning and many can turn around nearly within their own length. The possible difficulty you may have is the fact that you will have a 2400 lb hull plus the weight of all your fixtures and equipment with only a 70HP maximum rating. You could also think about using bow thrusters, a much less expensive alternative, although there are pros and cons to the advantage of using them on boats the size of the Waterlodge. I would put that specific question to the GlenL teamfor a more definitive answer.

rjw
Posts: 18
Joined: Thu Jan 03, 2013 2:33 pm
Location: Near Toledo OH

Re: Twin outboards

Post by rjw » Sat Mar 02, 2013 5:09 pm

Thanks -

I'm not sure how much horsepower I need - I'm looking to move pretty slowly (Old age <G>)

pamelalynne1
Posts: 398
Joined: Thu Jul 29, 2010 3:55 pm
Contact:

Re: Twin outboards

Post by pamelalynne1 » Sat Mar 02, 2013 8:25 pm

Two 35 hp outboards will not give you the thrust of one 70hp as was mentioned earlier. In any case, a 70hp is not going to break any speed records. I almost goofed and said "at any rate" :lol: I still think this is really a question for someone with more expertise on the subject.
And stop complaining about old age. I have two great grandchildren and I am just finishing my Stiletto ski boat build; and I might have to build something faster. One of my friends has a Sutphen jet boat called "Blew By You" that does over 70; and I have to be able to keep up with him. We started racing each other when we were teenagers.
Never underestimate the determination of an old lady. :lol: :lol: :lol: :lol:

Post Reply

Return to “Small outboards”