Tolleycraft 40 Fuel Burn

[m20e]

Hi all
I'm a new member looking to buy a Tolleycraft 40 with twin 3208T Cats. The boat has a modified V hull and a listed max speed of 25kts and cruise of 12 kts.. It has a stern thruster, why put a thruster on a twin?
I'm thinking I 'd like to cruise at 8 kts to lower the fuel burn. Is this feasible or should I buy a boat with less power? What would be the fuel burn at 8 kts and 25 kts?

Why is a Tolleycraft not considered a trawler?

Thanks for your wisdom

[rslifkin]

You could never run 25 kts with that boat outside of a brief test run. Fast cruise will likely be around 18-20 kts. I'd expect about 0.8 nautical miles per gallon at that speed. Best slow cruise will likely be around 7 kts, figure somewhere between 2 and 3 nmpg at that speed. 8 kts is doable, but will burn more fuel than 7 and make more wake as well as 8 kts is pretty much right at hull speed (best slow cruise is usually a bit below).

[Ken E.]

Why a stern thruster? Just easier docking. Do you need one with twins? No. I don't have bow or stern thrusters. They would be handy at times but you can do a lot in close quarters with twins. Why isn't it considered a trawler? It's a planing hull with hard chines, ala 25 kts. Agree with the above, you'd never see 25 kts in the real world...high teens firewalled would be my guess. Lots of fuel consumed. The Cat guys here could tell you how much.

[rslifkin]

Originally Posted by Ken E.

Why a stern thruster? Just easier docking. Do you need one with twins? No. I don't have bow or stern thrusters. They would be handy at times but you can do a lot in close quarters with twins. Why isn't it considered a trawler? It's a planing hull with hard chines, ala 25 kts. Agree with the above, you'd never see 25 kts in the real world...high teens firewalled would be my guess. Lots of fuel consumed. The Cat guys here could tell you how much.

I'd think 25 kts is reasonable wide open. The cats are likely 375hp. My boat is slightly lighter and similar in size with slightly less power and runs about 25 kts wide open with a normal load. But max continuous is likely to be no more than 20 kts.

[Comodave]

Welcome aboard. Why have a stern thruster in a twin, because it makes it easier to handle. I put a stern thruster in our last boat which was a twin. I docked from the flybridge and by the time I got down to the stern to handle the lines it may have blown off the dock. Then back up to the helm on the bridge and repeat, sometimes several times. With the thruster and a remote I could just hit the thruster and no need to use the helm.

Tolleys are a planning hull not a trawler as said above. Nice boats though.

[m20e]

What is the drawback to a planning hull if I want to cruise at 6-8 kts? Is this a good choice for a loop boat? Thanks

[rslifkin]

Originally Posted by m20e

What is the drawback to a planning hull if I want to cruise at 6-8 kts? Is this a good choice for a loop boat? Thanks

It depends on the boat. A planing hull that cruises in the teens will often handle fine at lower speeds, particularly if it has decent size rudders. There may be some conditions where it's more comfortable or better for handling to speed up, but you can certainly run a planing hull slowly with reasonable results. We run our boat at 6.5 - 7 kts most of the time despite being able to cruise at 17 (with much higher fuel burn).

From the pictures I can find of the Tollycraft 40 hull I'd expect at least decent low speed behavior. It will be a little worse handling and maybe a little less efficient than a slow boat. But that's the trade-off for the ability to go faster sometimes.

[Comodave]

We went from a trawler to an express cruiser. We had our reasons. We usually run the express cruiser at about 10 MPH. It is fairly good efficiency wise but not as good as the trawler. But we went from 450 total HP to 900. So we expected a bit less efficiency. We had a boat about 12 boats ago that was a knock off of a Tolley 43. It was a superb handling boat. We had it in 18’ seas off the west coast and it was great, if a bit of white knuckle. Tolley did design some great hulls.

[SeaDogAK]

My old Tolly 37 wallowed in the seas uncomfortably at 7-8 knots. It was much more stable at 12-14 knots, though the fuel burn was of course higher.

[m20e]

Thanks for all the great info. This will certainly help me keep from making a mistake.

[Mischief Managed]

I have essentially the same boat as the Tolly 40, mine just has a 4 foot cockpit added on. It will do 24 knots at WOT with twin 375 HP CAT 3208s.



My 44 likes an 8.5 knot cruise at roughly 1200 RPM. Any less and the turbos don't warm up enough and don't produce any boost, thus oil seeps into the turbo intake housings through the turbo bearings and seals. Makes an embarrassing cloud of blue smoke the next time you throttle up, and it can't be good to run that lightly loaded for long.



I would recommend running at a minimum of 1200 RPM with occasional bursts to 2200 RPM for a few minutes to keep things heated up. Fuel burn on mine at 1200 RPM/8.5 knots is between 2 and 3 NMPG.

[Kintala]

Before you buy the boat, go watch this episode of Searching for C-Shels:

https://youtu.be/gtAhRzO0WGs

[Jeff F]

Originally Posted by m20e

Thanks for all the great info. This will certainly help me keep from making a mistake.

What kind of mistake are you concerned about making?

[Comodave]

Originally Posted by Kintala

Before you buy the boat, go watch this episode of Searching for C-Shels:

https://youtu.be/gtAhRzO0WGs

Amazing how much it cost.

[seadancer]

Welcome! I have twin Cat 3208's (naturally aspirated - no turbos) in my 37' Canoe Cove. I think they are rated at 250 hp. I call my boat a "fast trawler" because above the water line, it looks sort of like a trawler, but has a semi-planing hull. It handles very nicely in the 10-12 knot range (1800-2000 rpm), but the rudders are small, so at slower speeds not very effective, so at slow speed, I steer with the throttles, and maneuver in tight spaces and dock with the transmissions. At 10-12 knots, I get (very approximately) 1 nm/gallon. I might get slightly better economy at slower speeds, but I don't cruise long distances and I'm a bit of a "lead foot," and I like to get where I'm going. I don't know if any of this applies to your Tolly.

[m20e]

Thanks for all the replies. I must say with all the choices it gets confusing.
I should add that I owned a 40ft sailboat for about 10 yrs but definitely would not call myself an accomplished sailor. Add to that I've had 6 lower back surgeries with limited mobility. I'm 73 and go to the gym daily and except for my back I'm in good shape. My plan is to hire someone with a 34-40 ft trawler to take me out to assess my abilities. Good plan? Do you know anyone for hire? Thanks

[Pete Meisinger]

When you consider that my 36 foot Albin does just fine with 120 hp. It kind of makes me pucker to think of 800 or 900 hp in a boat, although a slightly larger boat.

Then to take that thought one step further, thinking of those two monsters screaming away at 4 or 5 thousand rpm is beyond my comprehension.

Different Boats for Different Folks, I guess..

pete

[m20e]

Originally Posted by Kintala

Before you buy the boat, go watch this episode of Searching for C-Shels:

https://youtu.be/gtAhRzO0WGs

WOW I just saw this and I must say I've been a trucking company owner for 40 yrs and thought I'd seen it all until I saw this. That's an insane price for a Cat rebuild. Maybe I should look for a Lehman because I really don't need the power lol.

[Mischief Managed]

Originally Posted by m20e

WOW I just saw this and I must say I've been a trucking company owner for 40 yrs and thought I'd seen it all until I saw this. That's an insane price for a Cat rebuild. Maybe I should look for a Lehman because I really don't need the power lol.

It's mostly labor for sure. The engine has to be stripped down to a short block in the boat to come out the side door and then has to be assembled in the boat when the rebuild is done. It's a LOT of miserable work. That said, it does seem incredibly expensive to me too...

[Comodave]

I was astounded by the cost. I would have guessed about $30K.