3B as a boat motor?

[JoeCanadian]

just firing it out there. i'm planing to build a 22' aluminium boat. cabin cruiser style and was thinking a 3B, 3B-T, 13b-t would make a sweet, cheap to run and very reliable way to go. was thinking of keeping it freshwater cooled by welding a heat exchanger to the bottom of the hull. not sure what leg to use or even how it will mount to the motor. i think you could go a long way with a 150-200 gal tank at 2400-3000 RPM.

anyone see this as a good or bad idea? input guys, i need input. has anyone seen a 3b as a boat motor?

thanx for any input,

[lynchmob]

There are some Hino marine engines that I believe are 14B or 15B engines. Maybe the parts are already out there to make it work

22' seems like a small boat for this engine though - there are probably much better options.

[Granite Grinder]

I thought I read a boat anchor, silly me.
GG

[lostmarbles]

Originally Posted by Granite Grinder

I thought I read a boat anchor, silly me.
GG

x 2 (I could name a few MUD members here who might contemplate such an end-use for their 3B.)

[JoeCanadian]

well, i didn't think 22 feet was to small? i just dont wanna be a slow poke eh.

[roscoFJ73]

Originally Posted by JoeCanadian

well, i didn't think 22 feet was to small? i just dont wanna be a slow poke eh.

It really boils down to cost and what you are getting for your money. It may well be cheaper to find a used marine diesel ready to go.


As far as power goes,most 22 footers have 100+ HP ,so the 3B will be at the lower end of the HP scale.

[lynchmob]

Originally Posted by roscoFJ73

It really boils down to cost and what you are getting for your money. It may well be cheaper to find a used marine diesel ready to go.


As far as power goes,most 22 footers have 100+ HP ,so the 3B will be at the lower end of the HP scale.

yeah, but how many 22' boats have diesels? Are we talking about a net boat that you are using in the bay or what?

A 100HP gas inboard would likely be a 4cyl that weighs less and takes up less space.

[JoeCanadian]

Originally Posted by roscoFJ73

It really boils down to cost and what you are getting for your money. It may well be cheaper to find a used marine diesel ready to go.


As far as power goes,most 22 footers have 100+ HP ,so the 3B will be at the lower end of the HP scale.

yeah, it would be at the lower end on the hp but how about the tourk end. as far as cheap go, i already have a 3b

[RHINO]

joe the problem with the 3B in a boat is the power to weight ratio. its not that the engine puts out less that 100hp but that the engine is so heavy doing it. a diesel is a great marine engine but you want something with more RPM and less weight.

on a different note i always wanted to check out a mazda rotary in a boat.

[JoeCanadian]

on a different note i always wanted to check out a mazda rotary in a boat.[/quote]


yeah the rotary would be sweet in a 12-16 foot sport jet boat

[gettocruiser]

i worked in a couple boat building shops, not that i am an authority. but i believe it would do okay in a smaller boat. don't expect it to be fast.
someone already said it, it might be cheaper to buy something ready to go. i know to marinize an engine requires marine manifolds and lots of custom plumbing and fitting. finding a bellhousing won't be fun.
to put it into perspective, last summer i bought a 21' glass boat. power was a in board chev 350 with a duel prop volvo leg. it needed work but i paid $2000 for it.
doing anything custom is hugely expensive... buy something someone else went broke building.
oh, that boat i described used about $50-100 per hour worth of fuel. 3b wouldn't do 25mph but would run all day for $100.

[canucksafari]

The 2.5L Mitsubishi would probably be better suited diesel for a boat: smaller, lighter, more hp and higher reving. It seems to do fine pushing boats on land. I know one guy that says he drives at near a constant 4000 rpm on the highway in his Delica.

[MOTERRA]

thats funny when I got my bj60 my neighbor suggested "that would make a good boat motor"

[roscoFJ73]

Originally Posted by lynchmob

yeah, but how many 22' boats have diesels? Are we talking about a net boat that you are using in the bay or what?

A 100HP gas inboard would likely be a 4cyl that weighs less and takes up less space.

Maybe we are diesel spoilt ,but a diesel 22 ft pleasure boat would not be uncommon here .
Yanmar,BMW, Ford and Volvo all have marinised diesels in this class with inboard engine and outboard leg.
In fact almost everything over 25 ft is diesel.

The type of hull is a big factor.If its a non planing hull it will have low hull speed and nothing will help it go faster.


One good point about the the 4 cyl diesel in a boat this size,it may double its range over a gas ouboard chugging away at 1800 rpm

[freebie]

Rosco makes a good point about the type of hull and your expectations? the 3B is not going to take a 22 foot cabin cruiser up on plane and go fast most likely?
If you want a boat that will get up on plane you need to pick a hull, find the weight of your boat, displacement etc, and find out how much engine is required. The more important issue is finding a gear box to mate up with the 3b that will give you the correct prop speed at a reasonable rpm to get you up on plane.
If you just want to put along at whatever speed?, the 3b would be awesome! if you keep the revs down the 3b uses very little fuel and funs forever at lower rpm's.
Another point, in your area you need decent boat speed to run the tide and current? if you end up with a boat that won't run at 10 knots your going nowhere againest the tide!
Build the the boat but make sure the engine drive system is right for the boat, talk to the guys at the boat yards (mechanics) about the HP vs rpms and base your decision on that.
In my opinon and with limited knowledge, the problem with going fast on the water is you need high revs, or if the you can't spin the prop at the right speed for your hull you will have problems.
Connecting the cooling system to a non-marine engine could be a hassle but its possible, in the salt chuck its better to run a heat exchanger cooling system, the 3b would probably be ok with salt water but you don't want to risk engine failure if its not necessary.
This topic is endless!! your in an area with tons of marine experience use the local experts, there's lots of people with boat building experience in your backyard.

Cheers

[MrMoMo]

Yanmar uses toyota blocks (AFAIK)

The easiest way to cool a non marinized engine would be to "keel cool" it. This uses the hull (steel or aluminum) as a heat sink with the water on the other side. Many Tug boats use keel cooling, it can be very effective. Google it.

[toynut]

i vote for closed cooling system via heat exchanger and a v drive , the 3b as has been said would not likely alow you to plane unless you went with some exotic hull design , stepped or tunnel ect .

it would make a great displacment hull motor you probably know with a displacment hull that the longer your boat the more speed you can achieve , a 22' boat could have a semi displacment hull with a planing section that could possibly plane after building suficent speed with the use of trim tabs .

[toynut]

HULL SPEED LENGTH RATIO CALCULATION AND ANY BOAT SHARE WARE CALCULATOR LINK - SOLAR NAVIGATOR WORLD ELECTRIC NAVIGATION CHALLENGE


Displacement Hulls


some interesting reading if your into it .

[canucksafari]

Now I remember who you are JoeCanadian. Your the guy who tried to use your Cruiser as a submarine last year without and auxilary air supply. Thought you would have had enough of Cruiser gear and water.

As to your question, a lot also depends on the gearing and pitch of your prop and what you plan to use your boat for. If you are planning on pulling logs all day, then the 3B with a power pitch prop would probably be fine. However, like the others said, you would probably be better off time and cost wize by buying a used marine diesel with the leg intact.

[fjbj40]

You know.....not all boat engines use legs to tranfer power to the water! As a matter of fact most diesel powered boats do not use a leg. If you run a full or semi-displacement hull and drive the shaft out through the hull through a stuffing box you will do just fine. I read an article in Wooden Boat magazine about a fellow who built a semi-displacement hull. It was 28 feet long powered by a Toyota diesel engine from a car...1.3 ltr I think...it cruised at 8 knots with less than 1 gal /hr!
My family had a 32 foot full disp. wooden hulled cabin cruiser when I was growing up. It had a 85 hp perkins 4 cyl. engine...it would top out at 12 knots...no matter if you went full throttle,3800 rpm , or 2500 rpm...the hull was the limiting factor.
A 3B powered 22 foot cruiser is plenty powerfull, and will work fine, IMOP. It would be like a bj60 though.....slow but reliable.
On our cabin cruiser we had cooling pipes running outside on the bottom of the hull....recirculated cooling. We eventually changed it to salt water cooling....the perkins was designed to handle it and it was reliable.

Do the research...talk to boat builders!

Daryl

[expat]

FWIW...

Hinos are Toyota block. Older Yanmars used to use a Toyota block (6cyl). There must be a reason why you can't buy a marinized block now. You can buy marinized Isuzu and Mitsubishi truck engines still from Klassen in Vancouver.

My boat is 26' and I have a 42Hp BMW diesel in it. I am swapping it out for a Volvo or Yanmar 75Hp diesel. I expect to gain ~3.5 knots cruising speed. I now burn less than a gallon at 6.5 knots. I plan on doing 10 knots at 1.5 gph. I need to repitch the prop, swap out the shaft, make a bigger exhaust, and put in new engine beds. Engine is about 11K. Parts and some labour will cost another 3K.

The cost wouldn't be in the engine per se, but in the other components. You need a reversing gear, prop, shaft, manifolds (or keel cooler) exhast elbow and system (or dry stack).

1.34 times the square root of the waterline length (for a displacement hull) equals hull speed. Your 3B would make enough power and torque for a semi-displacement hull like mine.

BTW, anything to do with boats ain't cheap.

[JoeCanadian]

cool thanx for the input. i also worked for some boat builders "daigle welding and marine, and wolf boats." all i know is that i can run my 3b-t all day on 80 bucks. and i dont have a feather foot, its more like a brick.