Thread: repowering pontoon dinghy

iv got a boat lined up a 4m pontoon dinghy and will get a new outboard for it i plan on using it for everything from lake and sea fishing and diving and want to be able to use it for travelling around places like the Marlborough sounds etc. i see a lot of boats this size have options for 15-50 hp motors on them is it better to go bigger than you think so when loaded up with diving or camping gear etc and to have the extra grunt for getting back when at sea or a travelling a long way but then how big is too big? thanks in advance for any tips.

Ive got a 3.8 stabi dinghy alloy and run a 30 hp Yamaha, can get 3 pax, spare fuel and heaps of other stuff and still planes easily . I try not to go out in over 15knts of wind as the stabi is a wet sprayey thing.But from time to time one gets caught out in winds and sea conditions and the 30hp handles the jandal easily. I use the dinghy around Stewart Island waters and is bomb proof. I used to run 25hp but found that a bit limiting.

I had a heavy duty 4m Ramco with a 30hp. Was a dream with 3 POB but a bit tail heavy by myself, I shouldn't think that would be a problem with a pontoon. My best guess would be to go a bit bigger, 40 & 50hp Mercs are about the same weight so I'd probably got to the 50 if your budget allows as you may carry a lot more gear than I ever did.

got a 4m rockhopper , had a 30 mariner which was great and I put elec start on but got chance to up grade so went to a 40 yammy 2str but with power tilt elec and pull start don:t really need xtra power but the power tilt if essential ifworking round rocks etc as no leaving the helm to lift motor . watch the 4 strokes as the weight gets up there but the are eco a 40 etec would be nice .

i was beginning to lean down a 40-50hp 2stroke for a bit more power but after a bit more thought a 4 stroke would be better for economy and slow trawling plus for the same price as a bigger 2 stroke i can get a 30hp 4stroke with all the electric start and trim etc so that will also be nice

One of the few things I've learnt in this life is that you always want a bigger outboard. Go as big as you can!

This 3.8 was perfect with a 30

Mate's 390 Stabi dinghy runs amazingly with a 40hp 2 stroke. Going up to 50hp meant adding a lot of additional weight to the transom, which would have required additional strengthening, and the bum would sit lower, in a boat with very little freeboard.
Have gone spearfishing with 3 guys and gear (about 400kg - none of us are small)
We made a game chair for it, and mate went gamefishing solo with reasonable results.

Over the years it underwent modifications to things like steering, a small canopy, seating, but still remains at the heart of it, a 390 Stabi dinghy.

Amazingly stable and capable for such a small boat. Never seems to be lacking oomph, so 40 appears to be more than enough.

Very reasonable results by the look of it

Originally Posted by quentin

Mate's 390 Stabi dinghy runs amazingly with a 40hp 2 stroke. Going up to 50hp meant adding a lot of additional weight to the transom, which would have required additional strengthening, and the bum would sit lower, in a boat with very little freeboard.
Have gone spearfishing with 3 guys and gear (about 400kg - none of us are small)
We made a game chair for it, and mate went gamefishing solo with reasonable results.

Over the years it underwent modifications to things like steering, a small canopy, seating, but still remains at the heart of it, a 390 Stabi dinghy.

Amazingly stable and capable for such a small boat. Never seems to be lacking oomph, so 40 appears to be more than enough.

Attachment 238250

Thats a great looking little boat pretty much what i had in mind just want it capeable of almost anything.

Originally Posted by rugerman

Very reasonable results by the look of it

It came with challenges.
Large Mako sharks were very close to the fisherman when brought to the boat.
Logistics issue - marlin was longer than the internal room in the boat. He ended up getting the whole boat filled with salt ice around the marlin, covered it with a tarp, and drove from Taranaki to the Kapiti Coast with the bill and tail sticking out both ends of the boat.

I agree with what MB has said.
Always go for as many horses as you can.

Got a 4.5m alloy boat with a 100hp 4 Stroke in the garage. Skips along nicely.

Had a 3.8m tinny when was younger with a 25hp 4 Stroke at times wished it had more juice, would struggle to get on the plane with 2 divers and a heavier 70l chilly bin (full)

You rarely regret having to many horses as MB says but you definitely regret not having enough..

My experience of having had a couple of smaller pontoon boats, If the pontoons extend well past the outboard the weight of the motor is fairly immaterial if however the pontoons dont extend bugger all back or not at all past the motor then having a heavy donk is down right dangerous.

I agree with MB as well. However, the 'BUT' is as long as it does not compromise the balance of the boat at rest. having only six inches of free board in a 8-inch chop while fishing in a wind against the tide situation is not fun, pontoon or not.

Find out the weight of the outboard you're interested in then load it up with the same weight all stacked right down on the transom. if it sits all right at rest then go for it.