On Apr 24, 9:22*am, wrote:
"jamesgangnc" wrote:
I think you
are confused about how inboard engine boat cooling systems work.

No, I'm not confused. I've owned and maintained a number of inboards.
Moreso than I/Os. Both gasoline and diesel. *I'm apparently just not
communicating my thoughts very well.

All of them have a pump that supplies water from the outside.

And you can maintain them without hauling the boat in half the time
and half the effort of an I/O.

On the rest it's
usually mounted on the front lower side of the engine.

Good idea. No impeller in the leg at all? All of mine had an impeller
in the lower outdrive except one with it on the top.

As to the reason, it let them
build a boat with some of the advantages of an outboards but without the
finicky, easily damaged, aluminum 2 stroke engines.

And with a lot more power to push much larger boats. Outboards didn't
have nearly the HP back then as they have now. I think the basic idea
for the I/O was valid and sound. I just don't think the designers put
enough thought outside their box. They could have built a much less
complex and more maintenace free system. One with something more than
rubber boots between it and sinking. But they didn't and the market
responded by demanding huge outboards. Which it now has.
I'm not saying I/Os are a bad idea. I'm saying they could have been
less complex which usually means better.

Rick

Your earlier post "Whether or not they use a standard automotive pump
or a special marine design that's self priming, I'm not sure." lead me
to think you didn't understand. Because they all use both pumps. The
difference between the alphas and the bravo/volvo/trs/etc drives is
that the alphas continue to use the raw water pump in the leg while
the others used a belt driven raw water pump on the engine.

And you'll get no arguement out of me that the raw water pump in the
engine compartment is way better and much easier to service. I was
only discussing how it got where it is. The orginal merc drive went
through several minor design improvements to give us the 2nd
generation alpha we have today. And engineering wise it is still not
even close to state of the art. But it works and has proven to be a
pretty reliable platform. Volume made it extremely cheap at the bulk
level. That kept it around. Merc as well as others have designed
much better outdrives. They simply cost more and many consumers don't
appreciate the difference therefore consumers don't want to pay the
difference. That volume is changing and more modern i/os are a bigger
part of the market now.

I'm not saying the i/o is "better" that the other two propulsion
solutions. All 3 have their pros and cons. How those factor in also
depends on the application. In some situations the i/o pros make it
attractive.

And there really isn't a real higher risk of sinking because the i/o
has a rubber boot coupling the drive to the exterior prop assembly.
The i/o is far more likely to survive a high speed hard strike to the
drive train without compromising the hull integrity that a
conventional inboard. The i/o absorbes most of the force in the gear
train and typically destroys props, gears, and couplings. The i/o
physical unit is typically kicked up rather than sheared off the
transom. On a conventional inboard usually the prop shaft is ripped
out or severely bent and there is frequently compromise to the rear
lower hull or stuffing box. Of course the outboard installation will
also kick up and often can stand anything up to and including being
ripped clean off the back without compromising hull integrity.

I don't think the hp difference was all that great, merc had some
pretty big inline 4s and 6s early in the outboard game. While they
did not match the hp of the early small block v8 engines if you factor
in the weight difference they were pretty powerful engines. Inboards
with automotive engines already predated i/os. So the larger boats
did not need i/os. Outboards simply don't attract a significant part
of the consumer base. Never have. It's all about what sells first
and engineering is always second to that. That's not unique to boats,
that is true in everything.

JamesGangNC wrote:
And there really isn't a real higher risk of sinking because the i/o
has a rubber boot coupling the drive to the exterior prop assembly.

I'd get rid of that one too lol!

On a conventional inboard usually the prop shaft is ripped
out or severely bent and there is frequently compromise to the rear
lower hull or stuffing box.

An unprotected prop is like playing Russian Roulette where I live with
sandbars, oyster reefs, shallow water etc. A keel under the prop
means everything, and I mean all the way to the rudder. You don't see
that often with trailerable boats. Shamrock is one exception but I
don't think their keel protects the rudder either. I'd have to go
looksee. A Tunnel is another way to go. But the least fuel efficient
boat I've ever owned was a Penn Yann Tunnel Drive. It was great for
bumping along on shallow sandy bottoms but the prop was small and Gawd
that sucker drank fuel.

I don't think the hp difference was all that great, merc had some
pretty big inline 4s and 6s early in the outboard game.

My first I/O was a 225hp OMC in a 1971 23' Seabird. Back then, nobody
built an outboard transom into boats that size. I think the largest
outboard you could buy was maybe 125-130hp and even on a smaller boat,
it would drink twice the fuel of a 225hp I/O. I used to pass outboard
boats everywhere I went. Waaaay later on, after O/Bs became more
powerful, guys began repowering boats like mine by bolting an O/B
bracket onto them. I eventually sold my Seabird as is but a friend of
mine still has one just like it that he repowered. He claims the
improvement in speed and handling is like night and day. Not to
mention the weight loss for trailering.

Inboards
with automotive engines already predated i/os. So the larger boats
did not need i/os.

They did if they were trailerable and liked the kick up advantages of
an outboard. And we're talking about a different era here. Back then,
a 23', 5200 lb boat was considered a BIG trailerable boat.

Rick

On Apr 24, 11:56*am, wrote:
JamesGangNC wrote:
And there really isn't a real higher risk of sinking because the i/o
has a rubber boot coupling the drive to the exterior prop assembly.

I'd get rid of that one too lol!

On a conventional inboard usually the prop shaft is ripped
out or severely bent and there is frequently compromise to the rear
lower hull or stuffing box.

An unprotected prop is like playing Russian Roulette where I live with
sandbars, oyster reefs, shallow water etc. *A keel under the prop
means everything, and I mean all the way to the rudder. You don't see
that often with trailerable boats. Shamrock is one exception but I
don't think their keel protects the rudder either. I'd have to go
looksee. A Tunnel is another way to go. But the least fuel efficient
boat I've ever owned was a Penn Yann Tunnel Drive. It was great for
bumping along on shallow sandy bottoms but the prop was small and Gawd
that sucker drank fuel.

I don't think the hp difference was all that great, merc had some
pretty big inline 4s and 6s early in the outboard game.

My first I/O was a 225hp OMC in a 1971 23' Seabird. Back then, nobody
built an outboard transom into boats that size. I think the largest
outboard you could buy was maybe 125-130hp and even on a smaller boat,
it would drink twice the fuel of a 225hp I/O. *I used to pass outboard
boats everywhere I went. *Waaaay later on, after O/Bs became more
powerful, guys began repowering boats like mine by bolting an O/B
bracket onto them. I eventually sold my Seabird as is but a friend of
mine still has one just like it that he repowered. He claims the
improvement in speed and handling is like night and day. Not to
mention the weight loss for trailering.

Inboards
with automotive engines already predated i/os. *So the larger boats
did not need i/os.

They did if they were trailerable and liked the kick up advantages of
an outboard. And we're talking about a different era here. Back then,
a 23', 5200 lb *boat was considered a BIG trailerable boat.

Rick

That's why you're not designing boat propousion systems. Pay close
attention. Boats with i/o drives are not sinking because of a failure
inthe rubber boot onthe coupling.

JamesGangNC wrote:
On Apr 24, 11:56*am, wrote:
JamesGangNC wrote:
And there really isn't a real higher risk of sinking because the i/o
has a rubber boot coupling the drive to the exterior prop assembly.

I'd get rid of that one too lol!

On a conventional inboard usually the prop shaft is ripped
out or severely bent and there is frequently compromise to the rear
lower hull or stuffing box.

An unprotected prop is like playing Russian Roulette where I live with
sandbars, oyster reefs, shallow water etc. *A keel under the prop
means everything, and I mean all the way to the rudder. You don't see
that often with trailerable boats. Shamrock is one exception but I
don't think their keel protects the rudder either. I'd have to go
looksee. A Tunnel is another way to go. But the least fuel efficient
boat I've ever owned was a Penn Yann Tunnel Drive. It was great for
bumping along on shallow sandy bottoms but the prop was small and Gawd
that sucker drank fuel.

I don't think the hp difference was all that great, merc had some
pretty big inline 4s and 6s early in the outboard game.

My first I/O was a 225hp OMC in a 1971 23' Seabird. Back then, nobody
built an outboard transom into boats that size. I think the largest
outboard you could buy was maybe 125-130hp and even on a smaller boat,
it would drink twice the fuel of a 225hp I/O. *I used to pass outboard
boats everywhere I went. *Waaaay later on, after O/Bs became more
powerful, guys began repowering boats like mine by bolting an O/B
bracket onto them. I eventually sold my Seabird as is but a friend of
mine still has one just like it that he repowered. He claims the
improvement in speed and handling is like night and day. Not to
mention the weight loss for trailering.

Inboards
with automotive engines already predated i/os. *So the larger boats
did not need i/os.

They did if they were trailerable and liked the kick up advantages of
an outboard. And we're talking about a different era here. Back then,
a 23', 5200 lb *boat was considered a BIG trailerable boat.

Rick

That's why you're not designing boat propousion systems. Pay close
attention. Boats with i/o drives are not sinking because of a failure
inthe rubber boot onthe coupling.

I personally know of two. I've heard and read from reliable sources
about others. Boats sink for all sorts of reasons. I can't imagine why
you would think failure of a boot isn't one of them.

Rick

I have been guilty of forgetting to put the drain plug in several times.
The boat didn't sink, but we did get about 1 foot of water before I
noticed.

Yes, the boat can fill up with water if any of the boots in the stern
drive rupture. I didn't like the older OMC stern drives because it had
that over sized boot on the transom. Those could really get you in
trouble quickly if they gave way.

Jim Rojas



wrote:
On Apr 24, 11:56 am, wrote:
JamesGangNC wrote:
And there really isn't a real higher risk of sinking because the i/o
has a rubber boot coupling the drive to the exterior prop assembly.
I'd get rid of that one too lol!

On a conventional inboard usually the prop shaft is ripped
out or severely bent and there is frequently compromise to the rear
lower hull or stuffing box.
An unprotected prop is like playing Russian Roulette where I live with
sandbars, oyster reefs, shallow water etc. A keel under the prop
means everything, and I mean all the way to the rudder. You don't see
that often with trailerable boats. Shamrock is one exception but I
don't think their keel protects the rudder either. I'd have to go
looksee. A Tunnel is another way to go. But the least fuel efficient
boat I've ever owned was a Penn Yann Tunnel Drive. It was great for
bumping along on shallow sandy bottoms but the prop was small and Gawd
that sucker drank fuel.

I don't think the hp difference was all that great, merc had some
pretty big inline 4s and 6s early in the outboard game.
My first I/O was a 225hp OMC in a 1971 23' Seabird. Back then, nobody
built an outboard transom into boats that size. I think the largest
outboard you could buy was maybe 125-130hp and even on a smaller boat,
it would drink twice the fuel of a 225hp I/O. I used to pass outboard
boats everywhere I went. Waaaay later on, after O/Bs became more
powerful, guys began repowering boats like mine by bolting an O/B
bracket onto them. I eventually sold my Seabird as is but a friend of
mine still has one just like it that he repowered. He claims the
improvement in speed and handling is like night and day. Not to
mention the weight loss for trailering.

Inboards
with automotive engines already predated i/os. So the larger boats
did not need i/os.
They did if they were trailerable and liked the kick up advantages of
an outboard. And we're talking about a different era here. Back then,
a 23', 5200 lb boat was considered a BIG trailerable boat.

Rick

That's why you're not designing boat propousion systems. Pay close
attention. Boats with i/o drives are not sinking because of a failure
inthe rubber boot onthe coupling.

Jim Rojas wrote:
I didn't like the older OMC stern drives because it had
that over sized boot on the transom. Those could really get you in
trouble quickly if they gave way.

I had one of those. And yes, it was a concern in the back of my mind
but I never had a problem with it. The advantage though, was it was
right out in the open and easy to inspect. Any problem with cracking
or deterioration would be noticable right away.
Both of the boats that I saw sunk with my own two eyes were
Mercruisers, in their slips, left unattended. Both sinkings could have
been easily prevented with regular inspection but... just didn't
happen. I don't know why. To much trouble I guess.

Rick

I spray all my rubber boots & hoses inside and out with the blue liquid
UV protected tire shine stuff. Mobile detailers & upscale car washing
facilities use the same stuff. I don't know the actual brand name, but
this stuff costs about $25 a gallon. I will find out the brand name and
post it later.

I live in Florida, so any unprotected rubber will dry rot in the sun
within a few short years. Ever since I started using this stuff, all the
rubber on my car, boat, and trailers all shine like new. It seriously
protects without breaking down the rubber like other products do. You
can even spray this stuff on faded boat paint, and she comes back like
new. It lasts a long time. No rubbing, no buffing. The key is to let it
penetrate the paint for about a week or two for best results. Forget
that super expensive gelcoat rejuvenator stuff. This liquid stuff seals
it really well. I also sprayed the boat cover with it, and the water
still rolls right off a year later.

Jim Rojas



lid wrote:
Jim Rojas wrote:
I didn't like the older OMC stern drives because it had
that over sized boot on the transom. Those could really get you in
trouble quickly if they gave way.

I had one of those. And yes, it was a concern in the back of my mind
but I never had a problem with it. The advantage though, was it was
right out in the open and easy to inspect. Any problem with cracking
or deterioration would be noticable right away.
Both of the boats that I saw sunk with my own two eyes were
Mercruisers, in their slips, left unattended. Both sinkings could have
been easily prevented with regular inspection but... just didn't
happen. I don't know why. To much trouble I guess.

Rick

On Apr 26, 12:32*pm, wrote:
Jim Rojas wrote:
I didn't like the older OMC stern drives because it had
that over sized boot on the transom. Those could really get you in
trouble quickly if they gave way.

I had one of those. And yes, it was a concern in the back of my mind
but I never had a problem with it. The advantage though, was it was
right out in the open and easy to inspect. Any problem with cracking
or deterioration would be noticable right away.
Both of the boats that I saw sunk with my own two eyes were
Mercruisers, in their slips, left unattended. Both sinkings could have
been easily prevented with regular inspection but... just didn't
happen. I don't know why. To much trouble I guess.

Rick

Lots of boats sink in their slips. Just because they had mercs
doesn't mean that they sank because of the boot on the drive. You saw
the failed boot? Or you "heard" about from someone who "heard" about
it, etc. The boot very seldom fails just sitting unless they are old
and the drive is left tilted up. Which you are not supposed to do.
Anyone that leaves an i/o in a slip is not too smart anyway.
Especially salt water.

Phantman wrote:
Both of the boats that I saw sunk with my own two eyes were
Mercruisers, in their slips, left unattended. Both sinkings could have
been easily prevented with regular inspection but... just didn't
happen. I don't know why. To much trouble I guess.

JamesGangNC wrote:
Lots of boats sink in their slips. Just because they had mercs
doesn't mean that they sank because of the boot on the drive. You saw
the failed boot?

I'm a skeptic myself but I'm not sure why you're having such dificulty
believing this ;-) Yes, in fact I saw the boot and talked with the
owner of one, talked with the mechanic doing the rebuild on the other.
And yes I've seen boats sunk in their slips due to 100 other reasons.
Everything from a split hose attached to an open seacock to a transom
blown off due to fumes in the bilge when a charger kicked on.

The boot very seldom fails just sitting unless they are old
and the drive is left tilted up.

I don't know where your experience is but mine is southern salt water
and this sort of thing isn't all that uncommon here. Seems everything
in this marine environment gets old before its time.

Anyone that leaves an i/o in a slip is not too smart anyway.
Especially salt water.

100% agreed. And that's been my point from square one. I wouldn't say
the same for an inboard or an outboard.

Rick
PS... just noticed the NC on your name. Is that for North Carolina, I
presume?

wrote in message
...
On Apr 26, 12:32 pm, wrote:
Jim Rojas wrote:
I didn't like the older OMC stern drives because it had
that over sized boot on the transom. Those could really get you in
trouble quickly if they gave way.

I had one of those. And yes, it was a concern in the back of my mind
but I never had a problem with it. The advantage though, was it was
right out in the open and easy to inspect. Any problem with cracking
or deterioration would be noticable right away.
Both of the boats that I saw sunk with my own two eyes were
Mercruisers, in their slips, left unattended. Both sinkings could have
been easily prevented with regular inspection but... just didn't
happen. I don't know why. To much trouble I guess.

Rick

Lots of boats sink in their slips. Just because they had mercs
doesn't mean that they sank because of the boot on the drive. You saw
the failed boot? Or you "heard" about from someone who "heard" about
it, etc. The boot very seldom fails just sitting unless they are old
and the drive is left tilted up. Which you are not supposed to do.
Anyone that leaves an i/o in a slip is not too smart anyway.
Especially salt water.

We have had a couple of boats sink locally because of holes in boots. But
all those I know of were because the muskrats chewed the hole in the boot.
The Sacramento Delta has a thriving population of the little buggers.