Planing power for Inflatable?
 

Hi,

I've just bought a 9.5ft inflatable, and I'm wondering what's the
minimum power I need to get it to plane with 2 adults (say 400lb total) on
board?

I will be using the Trusty Electric for 90% of the time, but I may want
to scoot between the Gulf Islands of a day (ie park Far Cove at Wallace
Island and day-trip to Saltspring...)

Any thoughts? I'd think maybe 7.5, possibly 6hp?

Llyd Sumpter
"Far Cove" Catalina 36

No way. 15hp from a 2-stroke will have a heck of a time getting 400lbs up
on plane. You'd have to have one person in the front and the other leaning
forward. I've got a 9.5ft Nautica RIB with a 15hp Merc and getting on plane
with 400lb is tough. However once it's up, then it will fly, and the second
person can even sit in the back with me.

TT

"Lloyd Sumpter" wrote in message
...
Hi,

I've just bought a 9.5ft inflatable, and I'm wondering what's the
minimum power I need to get it to plane with 2 adults (say 400lb total) on
board?

I will be using the Trusty Electric for 90% of the time, but I may want
to scoot between the Gulf Islands of a day (ie park Far Cove at Wallace
Island and day-trip to Saltspring...)

Any thoughts? I'd think maybe 7.5, possibly 6hp?

Llyd Sumpter
"Far Cove" Catalina 36

Around 9/11/2005 6:02 PM, Lloyd Sumpter wrote:

Hi,

I've just bought a 9.5ft inflatable, and I'm wondering what's the
minimum power I need to get it to plane with 2 adults (say 400lb total) on
board?

Dunno about the minimum, but there are several 10' inflatables running
around the Port of Everett with 40 or 50 HP... Talk about overkill.


--
~/Garth - 1966 Glastron V-142 Skiflite: "Blue-Boat"
"There is nothing - absolutely nothing - half so much worth doing
as simply messing about in boats."
-Kenneth Grahame, The Wind in the Willows

On my 10ft dingy 15hp is the max recommended by the manufacturer. Any more
would be dangerous without substantial weight in the front. If I gun it
with just me in the boat, and I hit a small wave, I can almost flip it.
(I've flipped a dingy. It's kind of scary.) Plus, the weight of a 40-50hp
would make the boat permanently run nose up.

But let those folks keep tooling around with their 40 or 50hp engines. We
need a little chlorine in the gene pool. :-)

TT


"Garth Almgren" wrote in message
...
Around 9/11/2005 6:02 PM, Lloyd Sumpter wrote:

Hi,

I've just bought a 9.5ft inflatable, and I'm wondering what's the
minimum power I need to get it to plane with 2 adults (say 400lb total)
on
board?

Dunno about the minimum, but there are several 10' inflatables running
around the Port of Everett with 40 or 50 HP... Talk about overkill.


--
~/Garth - 1966 Glastron V-142 Skiflite: "Blue-Boat"
"There is nothing - absolutely nothing - half so much worth doing
as simply messing about in boats."
-Kenneth Grahame, The Wind in the Willows

Based on my experience, you will be happiest with a 15 hp assuming your
boat will handle it, and if you do not have to lift it unassisted. 7
1/2 hp will be very marginal at best, 10 hp I have no experience with,
but obviously somewhere in between. Scooting around is a lot of fun and
I recommend getting enough power to do it reliably.

Interesting...

First, my new inflatable is rated 8hp (I could probably squeeze on a 9.9),
and there's no way I'm gonna lift a 15hp+ 4-stroke around. Second, the 9.9
on the 12-ft aluminum I have gets 2 people planing no problem, and it's
WAY heavier than the inflatable. Third, the salesman said it would plane
easy with 6hp. He's lying of course, but I'd like to think he's not lying
THAT much... ;)

Anyway, if it takes more than 9.9, I'm gonna forget about it and just use
the electric (and oars). A lot quieter and less smelly. ;)

Lloyd Sumpter
"Far Cove" Catalina 36

On Tue, 13 Sep 2005 00:41:07 +0000, Tom "HappyFunBoater" Treadway wrote:

No way. 15hp from a 2-stroke will have a heck of a time getting 400lbs up
on plane. You'd have to have one person in the front and the other leaning
forward. I've got a 9.5ft Nautica RIB with a 15hp Merc and getting on plane
with 400lb is tough. However once it's up, then it will fly, and the second
person can even sit in the back with me.

TT

"Lloyd Sumpter" wrote in message
...
Hi,

I've just bought a 9.5ft inflatable, and I'm wondering what's the
minimum power I need to get it to plane with 2 adults (say 400lb total) on
board?

I will be using the Trusty Electric for 90% of the time, but I may want
to scoot between the Gulf Islands of a day (ie park Far Cove at Wallace
Island and day-trip to Saltspring...)

Any thoughts? I'd think maybe 7.5, possibly 6hp?

Llyd Sumpter
"Far Cove" Catalina 36

On Tue, 13 Sep 2005 00:41:04 -0700, waynebatrecdotboats wrote:

Based on my experience, you will be happiest with a 15 hp assuming your
boat will handle it, and if you do not have to lift it unassisted. 7
1/2 hp will be very marginal at best, 10 hp I have no experience with,
but obviously somewhere in between. Scooting around is a lot of fun and
I recommend getting enough power to do it reliably.

Thanks - see my other post. And thanks for replying to a boat-related
thread! :)

In my Younger (read: ligher!) days I played with a "bathtub boat" for the
Nanaimo-Vancouver Bathtub Race - that was a HOOT! 7.5hp, 6ft long...

Lloyd Sumpter
"Far Cove" Catalina 36

I'd guess that the 9.9 will get the job done most of the time but can't
say for sure. 6 hp or 7 1/2 hp will easily plane one adult but is
marginal for two. There's a big difference in planing effort between a
rigid bottom 12 ft boat and a 9 ft inflatable with a soft bottom.

When I was a kid my brother built an 8 ft hydroplane with a 7 1/2 hp
Merc on it. That thing would do 25 mph + but it had much less
resistance than an inflatable and would only hold one person. It was a
mite twitchy at speed to say the least.

Yeah, a 15hp 4-stroke would be heavy. I have a 2-stroke. I think the
weight is around 95lbs. I use a synthetic oil and it doesn't smoke too bad.
I went with a 2-stroke because I didn't think that a 4-stroke would have the
hole shot to get on plane. I could be wrong. I never test drove with a
4-stroke. Also, my main buying factor was weight. I needed to be able to
drag the dingy and engine around on the beach by myself. I think the total
weight is around 200lbs. My previous dingy was a 12ft with 40hp 4-stroke,
center console and it weighed 650lbs! I loved the speed, quietness and
comfort of that boat, but damn I got tired of trying to drag it off the
beach after the tide went out. It took three of us usually. Luckily I
flipped it and had to buy a new one. ;-)

I could image that a hard shell aluminum boat would plane with less hp.
RIBs seem to have a lot of drag. I can image you planning with 6hp in a
RIB, but only if you're not heavy and you lean WAY forward. If the boat is
designed well you might be able to plane 400lbs with a 9.9lb. But I doubt
you could do it with a 4-stroke.

TT


"Lloyd Sumpter" wrote in message
...

Interesting...

First, my new inflatable is rated 8hp (I could probably squeeze on a 9.9),
and there's no way I'm gonna lift a 15hp+ 4-stroke around. Second, the 9.9
on the 12-ft aluminum I have gets 2 people planing no problem, and it's
WAY heavier than the inflatable. Third, the salesman said it would plane
easy with 6hp. He's lying of course, but I'd like to think he's not lying
THAT much... ;)

Anyway, if it takes more than 9.9, I'm gonna forget about it and just use
the electric (and oars). A lot quieter and less smelly. ;)

Lloyd Sumpter
"Far Cove" Catalina 36

On Tue, 13 Sep 2005 00:41:07 +0000, Tom "HappyFunBoater" Treadway wrote:

No way. 15hp from a 2-stroke will have a heck of a time getting 400lbs
up
on plane. You'd have to have one person in the front and the other
leaning
forward. I've got a 9.5ft Nautica RIB with a 15hp Merc and getting on
plane
with 400lb is tough. However once it's up, then it will fly, and the
second
person can even sit in the back with me.

TT

"Lloyd Sumpter" wrote in message
...
Hi,

I've just bought a 9.5ft inflatable, and I'm wondering what's the
minimum power I need to get it to plane with 2 adults (say 400lb total)
on
board?

I will be using the Trusty Electric for 90% of the time, but I may
want
to scoot between the Gulf Islands of a day (ie park Far Cove at Wallace
Island and day-trip to Saltspring...)

Any thoughts? I'd think maybe 7.5, possibly 6hp?

Llyd Sumpter
"Far Cove" Catalina 36