Fastest boat with 3.5hp?
#1
Senior Member
Thread Starter
Join Date: Oct 2012
Posts: 1,170

Asking for a friend. What's the fastest boat you can plane with a 3.5 two stroke Tohatsu?
Off the bat I'm thinking maybe the Porte Bote. I think he may want something a little more rigid and simpler though.
Qualifications are:
Can't be made in China
Has to be simple
Has to be able to plane at 2/3 throttle with 1 person
Can't be chincy
Let me know your thoughts!
Off the bat I'm thinking maybe the Porte Bote. I think he may want something a little more rigid and simpler though.
Qualifications are:
Can't be made in China
Has to be simple
Has to be able to plane at 2/3 throttle with 1 person
Can't be chincy
Let me know your thoughts!
#8
Senior Member
Join Date: Oct 2013
Posts: 141

My brother and I had a 12' sears jon boat, 3.5 hp Chrysler air cooled.
With one of us aboard, and sitting in the center it would plane at WOT.
Of course that was over 40 years, and 100 lbs. ago!
The smile on our faces was priceless.
With one of us aboard, and sitting in the center it would plane at WOT.
Of course that was over 40 years, and 100 lbs. ago!
The smile on our faces was priceless.
#13
Senior Member
Join Date: Jan 2010
Location: Back in suzhou in China again
Posts: 3,366

Boost the hp to 6 and then you talking planning !!
I used to make a small 7 foot clinker fiber glass dinghy and my son used to race around the shallows in it and it planed no problem !,
Funny there was never ever petrol in the mower !
He even learned to old art of syphoning petrol out of the cars and mixing his own oil !
I used to make a small 7 foot clinker fiber glass dinghy and my son used to race around the shallows in it and it planed no problem !,
Funny there was never ever petrol in the mower !
He even learned to old art of syphoning petrol out of the cars and mixing his own oil !
#15
Senior Member

Join Date: Feb 2003
Location: M.Vineyard, MA
Posts: 13,399

https://www.google.com/search?q=minimax+hydroplane+plans&rlz=1C1CHBD_enUS 736US736&tbm=isch&source=iu&ictx=1&fir=U990oCjVgqW MDM%253A%252CVqubLTUpVzSumM%252C_&usg=AI4_-kQzzJOyAbWZI6sPoQdJ1HVB-78LZA&sa=X&ved=2ahUKEwjh2PjpouLfAhWJZd8KHVLPA1AQ9Q EwD3oECAQQDA&cshid=1547090972988001#imgrc=U990oCjV gqWMDM:
Mine was red with white stripe.
Highly recommended easy project guaranteed to put a grin on your face.
#16
Senior Member

Join Date: Nov 2002
Location: Pensacola, Fl
Posts: 10,996

I have a 9'6" air floor inflatable which weighs about 60#--I weight about 180 lbs--I use a 3.5 hp Merc 2 stroke as one of the dinghy motors---it goes about 8 knots top speed--not really planing however. You need very light weight--and well developed bottom surfaces to plane with that HP--and at that you are running the outboard WOT all of the time.... Not practical.
#17
Senior Member
Join Date: Feb 2012
Location: PSL, FL
Posts: 719

Minimax are great, multi generation tradition to build them in my family. Mine had 9.5hp and ran about 30. Wil build one with my son in about two years.
But I suspect he’d like something more useful, like a Lillistone Fleet.
But I suspect he’d like something more useful, like a Lillistone Fleet.
#18
Senior Member

Join Date: Mar 2005
Location: Boat,Town Cove, Cape Cod. Live south of Boston.
Posts: 1,416

Yeah , Baby!! I built a "MiniMax" hydroplane from Popular Mechanics plans back in jr-high wood shop. That was fun. It would fly even with a 3hp Evinrude. Wish I still had it. There were 4 glassed-in water-tight flotation compartments.
https://www.youtube.com/watch?v=gqTcuUMCwh0 ( 4 hr build in 8 minutes)
https://www.google.com/search?q=mini...990oCjVgqWMDM:
Mine was red with white stripe.
Highly recommended easy project guaranteed to put a grin on your face.
https://www.youtube.com/watch?v=gqTcuUMCwh0 ( 4 hr build in 8 minutes)
https://www.google.com/search?q=mini...990oCjVgqWMDM:
Mine was red with white stripe.
Highly recommended easy project guaranteed to put a grin on your face.
#19
Senior Member

Join Date: Feb 2002
Location: Saugus, Ma. USA
Posts: 10,962

Unfortunately, no. Inflatables in that range generally won't plane with a 3.5. The bottom has a little too much give.
Even going to a 3.5hp 2 stroke, with a replacement lower pitch prop, overinflating the tubes, and using some pvc pipe to hold the tiller so you can fit in the very bow, wind and small waves going in a favorable direction, you still only have a 50/50 shot at getting it to plane.
Even going to a 3.5hp 2 stroke, with a replacement lower pitch prop, overinflating the tubes, and using some pvc pipe to hold the tiller so you can fit in the very bow, wind and small waves going in a favorable direction, you still only have a 50/50 shot at getting it to plane.
#20
Senior Member
Join Date: May 2006
Location: Fort Pierce,FL
Posts: 4,507
