O/B Question

[Luna Sea 3]

I am looking to get into something more comfortable for next season. I have been looking and found boats in the late 1980's, 31' - 33' size, Flybridge, with twin I/B.

I never owned an I/B, so my question is, what is the difference in the fuel economy, winterization, cost to run, and maintenance compared to my present power of twin 175's O/B.

Also, how does the shore power work. Is it as simply as plugging it in and everything on your boat now has power.

Haveing a boat that size will be a new experience for me and debating to see if it is worth it. I am trading off speed for comfort as I am getting older.

[Duffman]

All I can tell ya from experience is I/O's and saltwater DONT mix. If your going to a 31 - 33', SERIOUSLY consider a true inboard.

[Luna Sea 3]

Thanks Duff. I seen them both. My question now goes to true inboard comparison

[CaptMarc]

I have a 35' boat with twin diesel inboard, don't get gas inboards. To winterize my motors, I run 5 gallons of Freezeban through each engine and put a bottle of diesel stabilizer in each tank, thats it for the engines. I usually change my oil before I put it away for the winter, a mechanic told me if the oil has more than 25 hours of running time, it is good idea. During the summer, you have to check your stuffing boxes to make sure they are ok, change oil when you are suppose to. With a diesel, there is no ignition system, so it is only fuel and air to make it run. Newer engines are mostly electronically controlled, they are a different animal. Not sure the logistics of what problems they can run into, if any.

[Luna Sea 3]

thanks for the feed back. Can I assume the Diesel gets more milage then gas, like it would in a car.

So the regular upkeep isn't any more extensive then having twin o/b.. ?

don't have to worry about mixing oil and gas.

[Capt. Debbie]

Capt.

Having been involved in hundreds a breakdowns, here are some observations- good and bad.

#1- Diesels are the way to go. But they are MUCH more expensive. Initial buyers in that size boat cheap down and get undersized diesels if at all. Like twin 200 hp's on a 36'. That boat will barely do in the mid 20 mph's. Also given you're looking used, you can only buy what's there. As such, diesels in that size used boat population are rare- maybe one in 50 have them at all.

#2 - I/O lower units fail regularly. Maybe not every year or two, but the nature of the lower unit with all that stuff swiveling around with exhaust gas, gears, and spent water make for a shorter 1/2 live. A good I/O run, from what I've seen is about four years before failure.

#3- I/O's are WAY more manueverable in tight circumstances like docking. Like an outboard you can point the props at where you want to go.

#4- You can efficiently use the I/O trim-tilt to trim a boat up instead of using the power robbing trim tabs that work by causing drag. It's more fuel efficient to trim drives than use the tabs.

#5- I/O/ can be tilted up should you run aground or run into thin water. With straight inboards that's not an option and you have MUCH more gear underneath should you ground hard. The struts, stuffing box and rudders can be bent or seriously compromised (i.e taking on water). on a hard grounding.

#6- The straight inboards do not have any lower units, but do have gearboxes and have a stuffing boxes where the shafts exit the hull. Some of the newer (more expensive0 like Cabo's) inboards have a special sealing system where if you are towed the drag against the props of being towed breaches the seals and you begin to take on water. They require you to lock down the shaft.

#7- You will have much more maintenance with I/O's than inboards because of the way they operate. A newer Mercrusier high end Bravo Drive (duo props) could be cost to $10,000 should you have to replace the unit with new. Most people rebuild though.

BOTTOM LINE-
BUT for higher maintenance, the I/O is the superior unit for versatility to the straight inboard. INboard is much more simple and does not have the stress of a gimballed prop hooked up to 350 or 375 hp motors.

NOW look at the new digitital propulsion systems hawked. The new Azimuth style(i.e. joy stick steering) drives are variations on the I/O mounted moved to the boat's bottom instead of the transom. Those even have forward facing props and can not be raised. You want to run aground with those babies, you have have a single shot pistol handy to eat the gun when you get that repair bill. LOL

I hope that helps some?

Capt. Frank

[Capt. Debbie]

SHORE POWER
SHore power depends on how it's wired. You bring in 30 amp 120vac to a screw on connector. That SHOULD go to a main AC Breaker and better yet a panel. The AC should power a MARINE battery charger that will help keep your batteries up, and the DC power flowing with out sapping the batteries.
The AC panel COULD power electric water heaters, electric stove, reverse cyle (AC & Heat) systems. And of course should have GFCI outlets. This is oftern plug connected to Microwaves and TV/Entertain electronics.


FUEL ECONOMY- Diesel v Gas
Diesel, depsite being a MUCH HEAVIER block wins on fuel economy. But remember here what we are talking about in a boat in the low 30 foot class? It's a heavy boat to start with. A set of 350hp's may optimisticly get you slightly less than 2 mph on the cruise. A comaparable diesel may be about 3 mph. Does not sound like a day and night difference. But that's 50% better fuel economy

ENGINE LIFE NOT MENTIONED But a big difference
Assumin both gas and diesel are well maintained the diesel should get you many more hours of engine life. So instead of running on barrowed time with 1200 hours of a gas boat, the diesel is well inside it's prime.


MECHANIC & PART - diesel v gas
The number of diesel mechanics v. gasolene mechganics is striking fewer. So repairs may take longer to come but with a limited supply of diesel guys. And even that varies by brand. For instance Volvo Penta diesels are great engines, but their supply chain in this part of the US stinks. So you'll have to wait much longer on parts vs. other diesel manufacturers like Yanmar, Detroit, etc.

Capt. Frank

[Luna Sea 3]

wow.. great information.

I run a 26' CC with twin Evinrude 175's outboards.

I was thinking of going older but larger, flybridge with full cabin for more comfort.

Just trying to debate if it is worth the change, overall.

[Capt. Debbie]

You want a sleep aboard? You're going to be paying and lugging around a few thousand pounds more boat.

You doing Canyons? Need seaworthiness for the possible beatings you run into from time to time. I loved by 25' Grady. It was twin 200's and had a cuddy cabin. Ok to sleep on, but spending a weekend was taxing.

My favorite ( If I hit the lottery) had been a 31' Rampage with diesels. Canyon range and marginal comfort.

The trend now is for FAST Center Consoles or non-walkaround cuddys with a shit load of O/B's ( 3 or more) on the back. Deep V and cruise in the 40's with top speeds near 60-70 knots. No more 5 or 6 hours party boat runs for you. Three hours to Hudson Canyon. You could leave the dock in Belmar after work at 5PM and be hooked up at Hudson before the sun even goes down. Wild! But BIG $$$ on engines. Ironically O/B's too.

Any bigger than low 30 foot range, in my opinion, the boat is too hard to run yourself with docking and stuff. You fishing alone may be the decider here on what size works. Forget 38's, 36's. I ran a 32' and that was scramble to dock alone, or have landlubbers who are clueless and just stand in the way.

Capt private message me if you have any thoughts. OK?

Capt. Frank

[penn50w]

Originally Posted by Luna Sea 3

I am looking to get into something more comfortable for next season. I have been looking and found boats in the late 1980's, 31' - 33' size, Flybridge, with twin I/B.

I never owned an I/B, so my question is, what is the difference in the fuel economy, winterization, cost to run, and maintenance compared to my present power of twin 175's O/B.

Also, how does the shore power work. Is it as simply as plugging it in and everything on your boat now has power.

Haveing a boat that size will be a new experience for me and debating to see if it is worth it. I am trading off speed for comfort as I am getting older.

Comfort is good. The big question is: How much do you want to spend before everyone tells you what to buy? Penn