Murry and Eric,
In all of my years of boating, all of them, some 70 years, yes at 5 years old I had a 6 foot punt that my dad would take me out. So I believe that I can speak to the subject of having a OB as a emergency method of removing yourself and boat out of a situation.
As Eric and many know, a small OB is often used as a fishing motor to reserve the use of the main engine which may be a fuel issue or too large to slow the boat down to trolling speed. I add that the application is seen often on those 35-40 foot single engine boats, not common, but you know what? I bet if you spoke to them you would find that what ever the size, the secondary thought will be the use as an emergency git-a-home.
As such, the OB becomes a git a home motor. There is no special reason to address it as that, it just is because it rides with you all the while. It is a part of the enviroment.
So- I have never been 'Pooped" under main engine power, nor when I am fishing at slow speed using the OB. You should have the correct shaft length at time of purchase. Now let me be clear. There is many cases of boats being 'pooped' and I can tell you why. The boat has a large OB main engine with a small kicker for trolling. The stern height is usually the fault as the heavy large OB keeps the low stern down in the water.The small kicker is being used as the trolling motor and with the added weight of the people on board standing or sitting aft,during following seas, are unaware of the 'Pooping happening. Under git a home conditions the kicker on a size boat like this depicted, will be turning at a high enough speed to move the boat with the following sea sufficiently to contend with following seas, Now if the following seas are surfboard quality, then of course all stern seas present conditions that will risk any boat.
The four knot speed is the speed we pushed the boat when ever we used the 9.9 as a fishing motor and moving from one point or short move to another potential fishing area. So as to flood or ebe with the motor in our case is mute as we could travel at full throttle if the tide ran against us.
I would agree that moving at what ever speed to a safe anchorage is Paramount when you are experiencing a stressful issue, particularly if you have the wife and family on board. When you experience a serious mechanical issue it usually includes ugly weather. I can guarantee you that your pucker factor goes up quickly as you contemplate action to secure the boat and family.
As the discussion regarding single /twin engine has been moved, It is anticipated that what and why of having the OB as it relates to being a git a home will not open the usual "Buy a twin screw boat".
While it is easy to say "If you can't afford them, then don't be in boating". I have heard that often enough. Let me inform all the posters, I am not able to afford twin screw, I can not afford a large 40 foot trawler. A git a home OB is the solution for me and it has been for low, these many years on the water.
Eric, as to the use of cell phone vs: VHF. I have many commercial fishing acquaintances. In discussions with several, particularly those who I have attempted to contact via VHF as we pass, I find that they have turned the VHF down and use their individual cell phones. The practical reason is they are able to converse in private regarding passing fishing information to each other without having the whole fishing fleet listen in on the "Scoop". When I speak to Tug operators, it often is the mode of communicating with the office. I have no idea what makes them shift to VHF when they are out of cell tower range.
When the question of diesel or propane OB develops, the immediate thought is 'sure, and as dealers are right up there with "Dodo" birds, you can anticipate zip on service, not to speak to purchase price. Emagin being off in the boonies with a diesel/propane OB and seeking help from traditional OB dealers. Just seems to beg the question of even adding such to your boat for emergency need. Pick an OB that you know dealer support will be available. Not trying to be argumentative, just realistic
The storage of OB gas is open to debate, however, with the OB fuel tanks constructed as todays tanks are, it is a stretch to say that it is an overriding deciding factor on installing an OB for the purposes stated. The installation is a common as cat hair here and the issue of stowage for the tank pretty much takes care itself. The more important issue is securing the tank so it doesn't walk off with thieves, a subject for another thread.
I have gone long here and for that I apologize.
A.M.(Al) Johnson-Ketchikan
Marben 27' pocket trawler