Engine size when using twins

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Well, I guess now he's outed it himself and it's no longer a secret, I can confirm in a PM or email Marin did hint to me some time ago he had plans to one day to have a boat built which was 'fast', and had 3 engines…

Looks like he went and did it...

I don't think the word "have" means the same thing to everyone as the word "own". If you rent a Ferrari, you "have" it, but you do not "own" it.
 
In this case the correct word is own. With a partner. The boat was designed and built to our specifications.
 
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There's a mid 70's 34' Tollycraft tri cabin twin screw needing new engines. Could be had for cheap!


Rip out the oldies and implant a couple 455 cid hopped up Buick beasts at 650 + hp with HD tranies. It too could hit into the high 40, mid 50 mph range. Probably at 75 + + gph.


The rugged Tollycraft hull will take it and with correct steering, rudder, and trim gear it will likely handle pretty good.


BUT - WHY??


I've been on Fountain boats that do the low 100's. Fun for a couple minutes, but after that - - > Again - Why!


I can see very high speed mid-sized boats for marine warfare; PT's being a great example. Can also see extremely high speed "ocean going" speed boats for hard-on excitement in races. Also can see hydrofoil racing for more hard-on type racing stuff.


After that - all I can ask myself is - WHY!!!
 
In this case the correct word is own. With a partner. The boat was designed and built to our specifications.

How fast, how big?? Picture, if you dare!
 
I've been on Fountain boats that do the low 100's. Fun for a couple minutes, but after that - - > Again - Why!

After that - all I can ask myself is - WHY!!!

The fact you have to ask why is the very reason you won't end up with one, but that's the way it is with all of us on boat types that don't fit for us. With Fountain being such a very small niche of the market, the indication would be the vast majority of people would say why. That's why their survival has been difficult, but ultimately you can survive with niche marketing at the high end of a market, while you can't at the low end.

There have been a lot of boat innovations and intriguing new ideas over the years that I was very attracted to, but obviously very few other people had any interest as they quickly disappeared if in fact they ever built any.
 
Re-read Tom's post #88 very carefully.

OOOOO - Top... err, Trade Secret. I like that!

I have some of that stuff too... so does Coca Cola!
 
There's a mid 70's 34' Tollycraft tri cabin twin screw needing new engines. Could be had for cheap!


Rip out the oldies and implant a couple 455 cid hopped up Buick beasts at 650 + hp with HD tranies. It too could hit into the high 40, mid 50 mph range. Probably at 75 + + gph.


The rugged Tollycraft hull will take it and with correct steering, rudder, and trim gear it will likely handle pretty good.


BUT - WHY??


I've been on Fountain boats that do the low 100's. Fun for a couple minutes, but after that - - > Again - Why!


I can see very high speed mid-sized boats for marine warfare; PT's being a great example. Can also see extremely high speed "ocean going" speed boats for hard-on excitement in races. Also can see hydrofoil racing for more hard-on type racing stuff.


After that - all I can ask myself is - WHY!!!

Art, any Tollies out there with diesels in them? More of a curiosity, but I'll bet a pair of 210 Cummins would do a very nice job and be very fuel efficient.

Ted
 
Marin,
You wrote,
"If American Marine made a mistake, in my opinion it was in not sticking with the amount of power the hull was designed for."

VERY VERY GOOD WORDS!

However I suspect Spray being wood and a one off build she was probably much lighter than the production 36.
 
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Art, any Tollies out there with diesels in them? More of a curiosity, but I'll bet a pair of 210 Cummins would do a very nice job and be very fuel efficient.

Ted

Ted

Vas majority of Tollycraft are north of SF; Oregon/Washington... even Alaska. Tollycraft turned out over 6,500 quality boats before its owner retired and the fickle finger of monetary fate took the company's new owners down for the count.

As factory originals, I believe nearly all 48' and above came standard with diesels. 44 and 45 footers seem to be 60/40 diesel/gasoline. 37 and 40 foot seem 40/60. Unless special ordered, I think 34' and below were gas.

A few owners have fitted diesels into 34' tri cabin or sedan. Cost to do so is prohibitive unless planning to keep for long time; generally there is a relatively low sales price in that size. A few 34' with diesel refit are for sale here and there. Prices are 2 to 3 x for the same boat with gas engines.

Gas power is affordable and works well in 34' and smaller boat... as long as the Captain knows how to handle/look-after area storage, tanks, fluid transmission lines, and venting of super explosive gasoline fumes! Gas engines are simple to use and nearly care free to maintain as long as regular service intervals are met. Parts are everywhere... so are mechanics if/when needed. Properly serviced, gently used 4,000 hours is easy to reach. Beat em and 1,000 to 1,500 hours (or even less) can bite owners in the butt. Gasoline engine replacement is relatively inexpensive and easy.
 
Marin,
However I suspect Spray being wood and a one off build she was probably much lighter than the production 36.

Eric--- As you well know, the first Grand Banks models, the 36 and 42, were also wood from their inception in 1966 to the middle of 1973 when both boats were changed to fiberglass from the company's new molds in their Singapore yard (the wood GBs were mostly made in Kowloon, Hong Kong although it's my understanding that some were made in the Singapore when that yard opened).

However, I'm sure you are exactly correct with regards to the weight of Spray vs the the GB36. As is obvious in a visual comparison, the GB36 has a considerably larger main cabin plus a flying bridge. I have no idea how the structures of the two wood boats compared, but Spray could very well have been built lighter as one of the requirements of the couple she was built for was "...a good turn of speed."

I would love to know--- as you probably would, too--- the reasoning behind the decision to fit the early GB36s with an engine that was a full 150 horsepower less than what Spray had.

Was the FL120 much easier to obtain in the numbers they needed for production work? Was the FL120 a lot less expensive than the Cat engine in Spray? Did American Marine feel that the majority of the customers for the GB36 and 42 weren't interested in cruising at the speeds Spray was capable of? Did American Marine feel the FL120 was a more reliable, longer-lived engine than the Cat in Spray?

Plenty of questions. Unfortunately, I've never seen any answers to them from the people who would know.

Below is a visual comparison of Spray with a 1974 GB36 (fiberglass). The fiberglass GB36s built from mid-1973 to 1988 were identical in dimensions to the wood GB36s. When the new molds for the GB36 and 42 went into use in 1988, both boats got a wee bit larger.

The GB36 illustration is the cover of the 1974 GB36 brochure. While the hull shapes underwater are identical, the changes that were incorporated into the production boat are obvious.
 

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OOOOO - Top... err, Trade Secret. I like that!

I have some of that stuff too... so does Coca Cola!

No, Art, no trade secrets or anything dramatic like that. It's just a boat, not the Enigma machine.:)
 
The GB has a higher profile than Spray. Spray looks more like the Coot without forward-leaning pilothouse windows and optional sails. But I doubt the hull designs are similar (workboat full-displacement versus semi-planing?).


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But I doubt the hull designs are similar (workboat full-displacement versus semi-planing?).

Yes, Spray has a semi-planing hull. That's why this 36' boat could do 17+ mph. The GB36 uses the exact same hull (the slight changes to the above-water profile in the sheer step are irrelevant to the hull's performance). And the larger GBs simply use longer, wider versions of Spray's hull.

So if we could put enough power in our 1973 fiberglass GB36, we could cruise at 16 mph all day, too. Unfortunately, American Marine chose not to do this until over two decades after they introduced the GB36, so we are stuck with an 8 knot cruise which most of the time is a major bummer.
 
.. we are stuck with an 8 knot cruise which most of the time is a major bummer.

Explains your interest in three-engined boats.
 
Zoom, zoom, zoon. The antithesis of "trawlering."


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Yes, life in the slow lane. With time to enjoy the sights.


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This is the kind of SD hull that will respond to power either single or twin and still glide along at 7-9K with little fuss. This is according to the designer a slightly modified lobster boat hull.
 

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This is the kind of SD hull that will respond to power either single or twin and still glide along at 7-9K with little fuss. This is according to the designer a slightly modified lobster boat hull.

Unfortunately without propeller, shaft, and rudder protection. You're not a mariner if you've never gone aground, nor a traveler if you've never been pickpocketed.
 
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Unfortunately without propeller, shaft, and rudder protection. You're not a mariner if you've never gone aground, nor a traveler if you've never been pickpocketed.

With a single this hull can have a narrow deeper keel and attached rudder as is common on all single engine lobster boats. With twins and the single keel not protected but there was the option for twin keelets attached to twin rudders there are some very successful boats of that configuration. Where I boat shoal water is 30 feet and the real danger is rocks and keels and skegs can just do so much against a rock at 8 or16 knots. As for the logs and crab pots vigilance is your best friend and a keel does not substitute for vigilance and is no guarantee of safety. The full keel thing may be over rated. On both coasts of the USA where I have boated the vast majority of motor boats had proud props and while some came to grief not that many compared to the many out there.
 
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The full keel thing may be over rated. On both coasts of the USA where I have boated the vast majority of motor boats had proud props and while some came to grief not that many compared to the many out there.
Maybe on the West Coast, but there is more than enough shallow water on most of East Coast to merit a full keel. In shallower areas, it's the sunken logs that I worry about. Often nothing to hint of their location till you have a bump. Feel much safer with the full bronze keel on my trawler and my stainless steel keel on the charter boat. Have bumped objects with both with no impact to the propeller. Struck a sunken navigation aid after hurricane Sandy that required replacing the keel on the charter boat (badly bent the shoe) but never touched the propeller.

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Ted
 
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Heck Eric

I wouldn't say you had bad words... just boat-luven words regarding your preferred type/design boat. We all have high praise toward our preferred boats. That's one of the many things that makes boat-luven so much fun!

Happy Boat-Luv Daze - Art

PS: How boring mariner pleasure-boat life would be if we all liked the exact same type boat!

Good point Art. It's healthy to have some to-ing and fro-ing in the posts, without getting personal.
Well done gentlemen!

... and have a good safe trip up the the Great White North, Eric! (not too fast though :) )
 
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Eyschulman,
What feature of your boat makes it a SD?
Looks like a soft chine planing hull to me.

Marin,
Looks like the black hulled Spray is higher in the water. I like the fish boat windows but visibility out the PH windows would be noticeably less. Looks like the PH is smaller but the main salon looks that much bigger. A wash I'd say. Like the straight sheer of Spray much better. Such a small thing but it seems significant. I hope you're not offended by this but if I had the money for a new Spray I'd want it the same except for the fwd end of the PH. There I'd like it to be just like the standard Nordic Tug. Oh ... and I'd want her white or GB beige. And if I didn't have the money to feed the Cat I'd want Spray's stern to be sculpted into a FD form w twin 47hp@2500 Mitsu's.
I think we discussed the weight difference between Spray and the GB36 on the past and as I recall they were about the same and I was very surprised. I think the GB36 is heavy like most all FG boats but the Spray could be whatever being a one off build.
Still reflect on an imagineary 21' GB OB hulled boat.
I remember that GB brochure.
 
A surprising thing with the IPS drives is the low incidence of damage due to groundings and strikes, this according to the yards and Volvo. Several reasons are cited such as more experienced owners, additional care and attention, avoiding shoal or shallow water and the cost to repair.

So what is it, on recreational boats is the protected keel thing just a "I have it so it is good," reason to get careless, sales and panacea gimmick or is it for real? BTW, good old Art put the keel below the props.
 
A surprising thing with the IPS drives is the low incidence of damage due to groundings and strikes, this according to the yards and Volvo. Several reasons are cited such as more experienced owners, additional care and attention, avoiding shoal or shallow water and the cost to repair.

So what is it, on recreational boats is the protected keel thing just a "I have it so it is good," reason to get careless, sales and panacea gimmick or is it for real? BTW, good old Art put the keel below the props.

All the above or some of all. I think those with protection are a bit more likely to go to places it might be needed, but the reverse was true that they knew they'd be frequenting such places so the protection was important in their purchase. On the east coast shoaling is going to be faced if you run the ICW. Our best protection is we run the vast majority of the time outside, especially in the worst areas.

Now, I'm not surprised that Volvo told you the incidence of damage was low and as to yards, in most areas the proportion of IPS to everything else is still quite small. One factor at play too is that boats with IPS do generally have shallower drafts, most of the time under 4', They aren't normally used on trawlers but on lighter weight sports boats.

I think regardless, everything else being equal one would prefer some protection but as with all boating decisions everything else is never equal.

And a reminder, that props are always the first thing mentioned but if all you have is prop damage, consider yourself fortunate. Props are the least of your worries. Oh, and on IPS, props only being damaged is even less likely.
 
Manyboats Why do I call it a SD? First the designer classifies it as such. Second there is no apparent hump when more power is applied the speed and motor strain go up in a fairly smooth fashion same as in a lobster boat. Third the lines are supposedly of lobster boat derivation. Perhaps the best answer to your question is that all SD hull are not the same and my hull leans toward the Fast SD category. Some of the LDL(light/length/ displacement) SD boats are even faster with less power. As T.R. pointed out the old concept of hull speed FD and SD and planning are murky. Most important to me the hull behaves very well at low speeds unlike some planning boats that are not happy campers at 7-9K.
 
Maybe on the West Coast, but there is more than enough shallow water on most of East Coast to merit a full keel. In shallower areas, it's the sunken logs that I worry about. Often nothing to hint of their location till you have a bump. Feel much safer with the full bronze keel on my trawler and my stainless steel keel on the charter boat. Have bumped objects with both with no impact to the propeller. Struck a sunken navigation aid after hurricane Sandy that required replacing the keel on the charter boat (badly bent the shoe) but never touched the propeller.

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Ted

Looking at your pictures it is apparent that you carry some draft. I zipped around the Eastern shore in thin waters for years with bare props as many others did but those props were only 2 ft or less in the water. Yes I know by experience any boat with 4 ft+ draft is going to find the bottom in the Chesapeake creeks and Barnegat bay so draft and location definitely come into the picture.
 
Eric-- Here is what Spray looks like today. Very different paint scheme. Can't say that I like it but it's definitely different from the original. Spray's interior configuration is more like a Nordic Tug, with the galley in the lower main cabin aft of the pilothouse with the stateroom portion aft of that. When American Marine designed the GB, they put the galley and day seating on the same level as the pilothouse and the now-smaller aft cabin became only a stateroom and head. This was a good move in my opinion because we and our guests much prefer the higher, better visibility of the GB's main cabin to the somewhat restricted visibility from the lower and aft-placed main cabins in the tug-style boats.

American Marine elected to keep the forecabin of Spray almost unchanged in the GB36 except the small head was moved to the starboard side.
 

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