Power Plant options

Hi,
New to your forum, looks like a lot of good info here.

Here's my deal.

We currently own a 26 Excel with a 454 brovo 2. We love our boat, and have spent weeks at a time on the boat.

We hope to spend some time in the San Juans up north, and do some of the great loop, soooo
we are looking for a project boat to work on for the next few years, sell the Excel, and go boating.

We like the 28' flybridge like Carver or Glasply. More stand up room, stand up head, flybridge, more fuel, more water, and twin engines.

The twin engines is where I get concerned. Although we like to wake board now and then, our main mode of operation would be at hull speed, or even slower.
I don't see a need for 600 HP to do this.
I have found some older boats with Merc 470's and Velvet vee drives, but have been told to stay away from these engines.

I have also found some boats we like with twin 5.0 (305 GM) power plants, but have been told they will burn around 1/2 gallon per mile each (one mpg combined).

If I can get this boat at a "good" price, could I repower with a couple 3.0 inline 4 GM engines?
Would the bolt pattern be the same, would the gear ratio need to be changed?
Would I have the option to chnage the rotation on these newer engines (in case the old 305 are set up reverse on one engine)?

I know about all the other things like mounts, exhaust, fuel, ....... no big deal as far as I can tell. I have the skill sets and equipment needed to build and or modify this stuff.

My real concern is this:
If I have to replace the vee drives becuse of flywheel differences or rotation, I don't think the deal is cost effective.
I also don't want to under-power the boat to a point that the engines will be working too hard. Leading to shorter engine life.

Any help or suggestions would be great.

Thanks
Bob

 

Happy New Year

Happy New Year

 

For displacements speeds get a displacement boat with 30hp motorpower and a waterjet for occasional fun...

 

Ya know, I'd me fine with that. In fact we have some Jetflees avalable to us.
Do you know of any makes/models that would be in the 27 to 28 foot range
and be "somewhat" trailerable?

I love the small trailerable tugs, but can't afford $75 grand.

Thanks
Bob

 

you can build a trailerable tug for about 4-5,000 US in wood https://www.boatdesigns.com/products.asp?dept=858

http://glen-l.com/designs/hankinson/titan.html Here is a bigger one. https://www.boatdesigns.com/products.asp?dept=741 Still trailerable with permit

you can build them in wood, steel, or aluminum.

 

Where is Four Corners?

I have a somewhat heavy 28 ft cabin cruiser on Puget Sound and get 1.25-1.75 knots/gal with a 454 at 10-15 kts or so.

Cruising at hull speed I can get 3-5 knots/gallon idling along. I have a flow meter and can track my fuel use fairly accurately. . Lighter more modern boats can go faster on the same fuel as mine.

Personally I think twins aren't worth the hassle of keeping up two motors.
But that's just me. Puget Sound is filled with great boats for sale for relatively little money with desperate owners eager to sell. I say buy a nice turnkey boat that is the one you want, but again that is just me. Even a turnkey boat will offer you lots of puttering about time and you will undoubtedly add all kinds of things to the boat, but again perhaps that's just me

The old guys tell me that Mercruiser engines are a poor choice. Everybody more or less uses the same blocks but the marine bits and pieces are different. Mercruisers have thin exhaust castings that can cause you trouble. My personal 454 is a Volvo. The swedes do a fine job of engineering but are extremely proud of thier spare parts. Crusader has a great reputation, that is what I wish my volvo was.

What ever you do good luck. If you have any more questions don't hesitate to ask. The San Juans are real nice but the hidden gem is...wait I can't tell you that or it won't be hidden any more. Have fun

TollyWally

 

"Cruising at hull speed I can get 3-5 knots/gallon idling along."

Instead,

One of the gas lawn mower engines or an old air cooled 20hp Onan or Kohler should work just fine to displacement speeds.

FF

 

Have a look at this:

http://www.boatdesign.net/forums/boat-design/tunnel-drive-performance-issue-23715.html

You can save tremendous amounts of fuel with different motorization, but achieving planing speed will be difficult. I am still working on refinements and will post the results as soon as the weather is suitable for test runs.

 

Trolly,

The four corners is the corner of Colorado, New Mexico, Utah and Arizona.

I will contune to lool for a single inboard with a somewhat small engine.

I don't really care about speed as much as I did when I was youger.
I would rather put a Buffet CD in and just cruse.

Anyway, I am headed over to Lake Powell on Monday to look at a couple boats, and see what I can do.

We really like our Excel 26SE, but you can't stand in the head, and it's a little cramped down below when the weather gets cold.

Galley is too small, and I really don't like the Deep V wonder when going slow.

We hope to get up to the San Juans this summer one way or the other.

 

Thanks for the info.

Can you give me some brand names I can google?
What sites do these people normally use?
Most boats that I find are "speed" boats with large twins.

Thanks
Bob

 

Sounds like you're a fair ways from any real water there, Bob
Just kidding of course. I've heard Lake Powell is quite nice. Lake Ontario (my home cruising grounds) is the little calm one in the Great Lakes basin, and it can still churn up a storm that'd give the folks in Puget Sound a run for their money....

I'm not surprised that you're finding a lot of speed-oriented boats with big twin engines. There's no shortage of those for sale here either. In the '80s and '90s, when gas was cheap, the trendy thing to do was to slap a lakefront condo on a 16' wide by 40' long V-hull, drop in a pair of 8+ litre motors, and advertise it as a luxury yacht that could do 30 knots. Well, they were luxurious, and they did do 30 knots. But try to cruise at anywhere from 8 to 24 knots or so, and the bow would go way up in the air, the thing would start chugging back the juice like college kids at a frat party, and the resulting wake would capsize fishing skiffs and wipe out waterfowl nests. After spending $400 per weekend on gas only to fork out $5,000 for a 90-pound mechanic who could fit down between the big overheated motors, owners simply put them back on the market.

Trying to repower such a brute with more efficient motors is not likely to gain you much benefit. The hulls simply aren't good at going slowly, and the smaller engines would be overloaded in the enormous "hump speed" range.

If you have no reason to ever go faster than 8 knots and you want an ultra-safe boat that can handle absolutely anything for less than a gallon per hour (but still fit on a trailer), it'd be hard to beat an Allweather, http://www.allweatherboats.com/

It does sound like the guys who have been suggesting two boats are on the mark. One little outboard thing, like a 16' Grew for sports and wakeboarding, and a seaworthy but slower large boat for your serious cruising. Don't be afraid to consider converting an old sailboat hull to power- not all are suitable, but if you find one that is, you might have a gem. Also don't be afraid to look at the commercial fleet. Some of the nicest, most economical power yachts I've seen were converted from fishing or cargo craft. The Sea Bright skiff form, the Down East lobster hulls, and numerous other "working" craft forms can be an excellent starting point for an efficient, seaworthy yacht- I'm surprised we don't see more of them.

 

Hey Bob,
The first and easiest place to look is Craigslist/Seattle. I'll try to hunt up some more sites but that is the biggy. Many of the ads will have pictures and the search function is pretty decent. After you narrow down some candidates you can google the brand names and email the owners. What people ask and what they will take are 2 different things as I'm sure you well know. A wise friend of mine told me something before I bought my boat. He said it is better to make a lower offer in the form of a question rather than a statement. After telling the buyer that he has a nice boat instead of picking it apart this would be his line.

"Would you be willing to accept X" as opposed to "I'll give you X"

In any event I don't mean to lecture you on the art of the deal. A guy with cash who is actually willing to buy now is a dream come true for the majority of boat sellers who are selling boats they actually own instead of boats that they are upside down on and are merely renting from the bank.

I haven't looked for a while but I am confident that with cash in my pocket I could have my pick of several damn good boats in a months time of casual searching. All boats are "project" boats but I see little reason to not buy a nice turnkey boat over one that "needs a little work". The turnkey one will be within 25-50% of the project boat price and will be lots cheaper than the project boat after it has been brought up to snuff.

My .02, your milage will vary. Feel free to PM me if you so desire. What ever you do good luck, maybe you could post a few pics of what ever you end up with.


TollyWally

 

I'll do that, and I should be up in the NW later in summer.
I did not go look at the 28' Carver at Powell this weekend, (lots of snow) but I did get a report back, that both engines (305) have the same firing order, and should, therefor both be turing the same rotation, this in turn means the counter rotation must be done in the Velvet Drives (one gear, one chain, drive).
I hope this opens up more options for repower? I have been told that all newer marine engines are all standard rotation?
No one responded to my other tread, I'm hoping the 3.0 inline 4 would have
the same flywheel housing bolt pattern as the 305's?

Thanks
Bob

 

OK Guys,
I have one more question, and then I'll take my leave and go look for boats.

What are some comments about removing the twin 5.0's all the gears and rudders, everything, and rebuild the boat with a single 5.0. Then add a bow thruster and maybe a stern truster as well?

All the stringers would need to be redone, and a lot of hole patching.

This this even doable?

Thanks
Bob

 

Counter-rotation is almost always done in the gearbox; engines of a given type virtually always spin the same way. The only common engines that can spin in either direction are a couple of snowmobile types, and a few older 2-stroke outboards (they're only supposed to spin one way, but a few can occasionally catch in the wrong direction if they don't build up enough momentum between when you hit the starter and when the first cylinder actually fires).

I don't know about the bolt pattern on the 305s. Your repower options should be pretty broad, limited mainly by what will physically fit in the engine bay. But do keep in mind that downsizing the engines in a boat intended for planing speeds may not work out all that well in the end.