Inboard vs. Outboard for Cruising

[newhaul]

Originally Posted by Don C L

...a supercharged outboard?... I like it!

They make them there is a company making diesel ones in Europe just can't remember the company name. But they do meet us EPA regs .

[newhaul]

Originally Posted by Jim Cate

There are a great many engineering successes.

And then there was the Tacoma Narrows bridge...

Jim

Actually Jim the original engineers design specs addressed the wind caused harmonics issue. But some contractor or politician decided open sided would not look good so design was changed without consulting the original engineering firm.
Grew up crossing the replacement one

[Adelie]

Originally Posted by Jim Cate

There are a great many engineering successes.

And then there was the Tacoma Narrows bridge...

Jim

A failure like that is how you find the limits of your knowledge. Happens in every field of endeavor Currently we are overdue for a major bridge failure, happens on a 30yr cylce. Either that or we have found almost all the failure modes for bridges.

[hsi88]

it was actually a field mechanic/engineer that suggested adding a supercharger to the merlin engine which made it as great a success as it was. But yes the rolls merlin was an awesome engine for fighter aircraft when they added the supercharger.

The precursor to the Merlin, the PV12 was designed from the ground up with a supercharger. They even used a supercharger when building single cylinder test beds. All Merlins came with a supercharger although the first Merlins were single speed. Wasn't until they utilized a two speed supercharger (also used in the Packard Merlin used in P51's) that the engine came into its own. Probably related to the reference made here. Basically two superchargers in series. Of note, the Merlin had a smaller displacement than other fighter engines of its day. One of the reasons for its superior fuel economy. A great design.

[newhaul]

Originally Posted by Adelie

A failure like that is how you find the limits of your knowledge. Happens in every field of endeavor Currently we are overdue for a major bridge failure, happens on a 30yr cylce. Either that or we have found almost all the failure modes for bridges.

Already happened
https://en.m.wikipedia.org/wiki/I-40_bridge_disaster
https://en.wikipedia.org/wiki/I-35W_...i_River_bridge

[Adelie]

Originally Posted by newhaul

Already happened

https://en.m.wikipedia.org/wiki/I-40_bridge_disaster

https://en.wikipedia.org/wiki/I-35W_...i_River_bridge

Sorry I did not full articulate my point. We are overdue for a major bridge collapse due to a previously unknown or poorly understood material or design weakness.

The last failure of this sort was a box girder failure in 1971 I believe. Prior to that there was a major failure leading to advances to the art and science of engineering and bridges about every 30-35y going back to the late 1700s.

The above 2 failures would not qualify. I-40 was not a design issue, the bridge was rammed. I-35W was a design mistake in sizing gussets rather than lack of knowledge of a weakness.

Ones again I incompletely expressed myself in that previous post.

[Cat36Mahalo]

Probably an old post - but have to contribute - Back in the 80's when I had my Catalina 22 and a 9.9 Honda on the back end - I was going thru a rip tide at the south end of San Juan Island (between San Juan and Lopez) - and on 3 separate occasions the outboard was submerged and stopped running. At first I was going thru without sails - but hoisted the main (reefed) for the other two tries - eventually gave up and spent the night in Fishermans Bay Lopez. At that time I vowed never ever to have a boat with an outboard. Just too scary to loose propulsion when you need it the most.

[thomm225]

Originally Posted by newhaul

Back to the topic now.
I noticed in your last video there was a good following sea but I didn't hear any change in the sound of your merc. outboard. Prop never left the water.

Yeah, it was kinda weird that it didn't. Mine does go down pretty low though on it's adjustable bracket

The waves got a bit larger near the shipping channel ahead and I believe it came out a couple times. This was a few months back.

When it starts to come out, I'll turn it down to near idle or shut it off depending on the situation.

The engine has an overrev governor on it also, but it takes a while to kick in. It will rev up quite high, but if the situation demands, it I'll let it continue to run.

Sometimes you can steer a different angle to keep it in.

[Cadence]

Originally Posted by thomm225

Where do you come up with this stuff?

This engine and this plane were built by engineers based on their office formulas. Both did pretty well in the real world in 1940

It is apples and oranges. I assume you are comparing to the comment about lazy jacks.

Yep, the Spitfire sounds good. Did they not have a Rolls Royce engine? I am not an aviation buff.

[thomm225]

Originally Posted by Cadence

It is apples and oranges. I assume you are comparing to the comment about lazy jacks.

Yep, the Spitfire sounds good. Did they not have a Rolls Royce engine? I am not an aviation buff.

No, not about lazy jacks.........

And yes, the Spitfire had a Rolls Royce Merlin Engine with 2 superchargers. By 1935 it developed about 1,045 hp

[Don C L]

Originally Posted by Cat36Mahalo

Probably an old post - but have to contribute - Back in the 80's when I had my Catalina 22 and a 9.9 Honda on the back end - I was going thru a rip tide at the south end of San Juan Island (between San Juan and Lopez) - and on 3 separate occasions the outboard was submerged and stopped running. At first I was going thru without sails - but hoisted the main (reefed) for the other two tries - eventually gave up and spent the night in Fishermans Bay Lopez. At that time I vowed never ever to have a boat with an outboard. Just too scary to loose propulsion when you need it the most.

Well I can certainly understand that but I have also had diesels quit on me at inopportune moments. Once in a shipping lane. The only solution is... oars! well, actually, wind is better, and stay out of shipping lanes if you can. Or near any shore.

[Cujo665]

Originally Posted by astokel

This is just my opinion. 4 stroke outboards are probably similar in fuel economy. Which costs more ; taking an outboard to a mechanic or having a mechanic come to your inboard? Which is quieter in the cabin; a well maintained four stroke outboard or an inboard?

I chose the outboard but recognise with larger boats an outboard may not be practical.

Having a tiller outboard as well as a rudder, I can turn almost within the size of the boat by turning the outboard and the tiller at the same time.

My thoughts exactly. The cabin remains usable even when motoring underway.
My 23 Oday has an 8.9HP 4 stroke that sips gas and has an alternator that charges the batteries. It pushes it along at hull speed set just barely above idle power. I literally motored over 9 hours on less than 3 gallons of gas once. A forward hatch mounted solar panel tends the batteries when the engine isn't running.

Fully adjustable mounting bracket makes it simple to adjust for proper position. Easy to lift out of the water to reduce drag, and then the tilt puts the whole head assembly right where needed for mx. It gets winterized and a tune up each season. Electric start is nice too. Using the engine tiller when docking makes it super easy to keep it in a slip.

[donradcliffe]

One of the other major differences between the inboard and the outboard is that the inboard heats up the cabin. Great for getting the dampness and mold, but not so great in the tropics.

[Stu Jackson]

Originally Posted by Adelie

A failure like that is how you find the limits of your knowledge. Happens in every field of endeavor Currently we are overdue for a major bridge failure, happens on a 30yr cylce. Either that or we have found almost all the failure modes for bridges.

We are due for massive bridge failures.

Due to a reluctant funding process from the R congress.

Gee, wonder why things fall apart?

Just like neglecting boat maintenance.

[SailingFan]

Originally Posted by hsi88

The precursor to the Merlin, the PV12 was designed from the ground up with a supercharger. They even used a supercharger when building single cylinder test beds. All Merlins came with a supercharger although the first Merlins were single speed. Wasn't until they utilized a two speed supercharger (also used in the Packard Merlin used in P51's) that the engine came into its own. Probably related to the reference made here. Basically two superchargers in series. Of note, the Merlin had a smaller displacement than other fighter engines of its day. One of the reasons for its superior fuel economy. A great design.

Especially when they finally figured out that a gravity fed carburetor was an unwise component in a fighter aircraft, and moved to injection after about the Mk VII (or perhaps IN the Mk VII)...