Trawler speed on a Tolly or Uniflite?

[Porchhound]

I just sold my really nice Silverton 34 because it wasn't practical to run her below planing speed, and currently too expensive to do it. At hull speed she would wallow around rarely staying on course without constant corrections. Wonderful boat, but poor judgement on our part thinking we could use her like a trawler.

So...it's almost impossible to find affordable (less that $70,000) North American built boats in the trawler category. I think I've seen comments posted from Tolly and Uniflite owners stating they can throttle back without issue even though they have planing hulls.

Any helpful comments would be appreciated

 

[rslifkin]

I do it with my planing hull Chris Craft all the time. In some conditions it's more comfortable to speed up, but we run at 6.5 kts a lot of the time. In general, slower planing hulls (design cruise not much above 20 kts) will tend to do better at low speeds than faster boats. As the boats get faster, keels and rudders get smaller, plus you often end with less gear reduction turning smaller props faster.

This is definitely an area where not all planing hulls are made equal. Some are good at going slow, some just suck at it. So you've gotta look at the design of each specific boat (and you'll want to at least see a picture of it out of the water) before deciding. There are plenty of people on this site running planing hulls slowly though.

My boat has pretty generously sized rudders for a planing hull, for example. I've never been short on rudder authority at any speed. It's also got a decent bit of keel compared to many planing hulls and has decent sized props with fairly deep gear reductions compared to many other planing hulls of similar size. The keel and rudders give it good tracking. In mild sea states it's not uncommon for me to go several minutes without needing to touch the wheel at all while doing trawler speed.

 

[Porchhound]

That is excellent information! Thanks. The Silverton, at 12k pounds and no keel to speak of and a small rudder, is even a bit of a handful during docking because she glides easily across the water, and spins around buoy or anchor while other nearby boats don't move.Even the slightest current or wind has to be accounted for.

 

[tiltrider1]

Uni’s and Tolly’s are fairly flat bottom boats with no keels and small rudders. They were designed to go fast at a time when fuel was cheap.

Yes, they can slow down and save fuel. I ran a Uniflite 42 for years at 8.5 kts. It more than doubled its mileage. The boat was never as comfortable at 8.5 kts as it was at 15 kts.

The turbulence created by a planning hull at slow speeds is huge. You are never going
to achieve the fuel mileage of full displacement hull or a semi displacement hull.

Can you live with planning hull at displacement speeds? I had an old Autohelm auto pilot and never worried about the small amount of wandering as I always ended up at my waypoint.

 

[Portage_Bay]

Californians at least the older ones were built in the US. The 42 LRC is very well behaved at trawler speeds. Canoe Cove is another North American builder.

Poor tracking may not always be the fault of the hull and rudders. When I first got the Californian she was miserable to steer by hand. I did a full steering system overhaul. Ram, helm pumps, AP pump and new lines. While it was all apart I had the joints at the ram arms to tillers bored and sleeved. She's a dream to steer now.

 

[rslifkin]

The turbulence created by a planning hull at slow speeds is huge. You are never going
to achieve the fuel mileage of full displacement hull or a semi displacement hull.

The planing hull shape is definitely less efficient at low speeds. But planing boats are typically lighter, so low speed fuel economy is often comparable to many similar size SD and FD hulls (the reduced weight offsets the less efficient shape). The more efficient FD hulls will do better, but not all FD hulls are that efficient.

 

[mvweebles]

If you're looking at sub-$100k trawler, you might consider a Monk 36, Defever 41, Ocean Alexander 40. Not US built, but decent quality. Because of keel, they are well mannered despite being singles.

I lived aboard a Uniflite 42 for a few years. Nice boat. I ran it at around 8 kts and it was okay. Viking 43 ACMY also comes to mind. Guessing you're on west coast, but some Hatts might fit into your criteria too.

Engine rooms on 42-foot motoryachts are a bit cramped for my tastes.

Good luck in your search.

Peter.

 

[Ken E.]

I always run my boat at 8 kts, which is a hard-chine planing hull with smallish rudders, but with a decent-sized keel. I find no problems running at this speed, having made many trips to SE AK.

 

[tiltrider1]

The planing hull shape is definitely less efficient at low speeds. But planing boats are typically lighter, so low speed fuel economy is often comparable to many similar size SD and FD hulls (the reduced weight offsets the less efficient shape). The more efficient FD hulls will do better, but not all FD hulls are that efficient.

What is the purpose of your post? There is always an exception? You will need to find a very poor FD hull to compare to a 70’s vintage planning hull for fuel mileage comparisons at 6kts.

 

[ancora]

Our planing hull Tolly was great at speed but when we had to slow down...a horror.

 

[rslifkin]

What is the purpose of your post? There is always an exception? You will need to find a very poor FD hull to compare to a 70’s vintage planning hull for fuel mileage comparisons at 6kts.

In the 40 foot range, it seems many people report typical fuel burn as 2.5 - 3.5 nmpg at a bit below hull speed across a pretty wide range of boats with diesel power The only exceptions to this are the more efficient of FD hulls like the Willards, Kadey Krogens and such. A little searching puts an N40 at about 2.4 nmpg at 7 kts, just shy of 3 nmpg at 7 kts for an N41 (right in range with the typical SD and P hulls). A KK42 shows a little over 4.5 nmpg at 7 kts, being a more efficient example of a FD hull. Nordic Tug 37s seem to be reporting 3+ nmpg at 7 kts. AT435 clocks in with 2.8 nmpg at 7 kts for another SD example. .

Basically, nothing will match the fuel burn of an efficient FD hull. But not all FD boats are that efficient. And they're usually heavy. Weight costs fuel, so the gains from a more efficient hull form can easily be lost to added weight.

 

[Jeff F]

Mainship 34 MY does pretty well as a trawler. Old but many have been refurbished/repowered. Nordic Tug 32. Great Lakes 33. There are a few. But they'd be smaller than your last boat.

Most of the boats that everyone immediately identifies as a trawler were imports.


Sent from my moto g play (2021) using Trawler Forum mobile app

 

[sbu22]

I lived aboard a Uniflite 42 for a few years. Nice boat. I ran it at around 8 kts and it was okay. Viking 43 ACMY also comes to mind. Guessing you're on west coast, but some Hatts might fit into your criteria too.

Engine rooms on 42-foot motoryachts are a bit cramped for my tastes.

Peter.

My Viking (43 ACMY) spends a lot of time at "trawler speed" - apparently has enough of the attributes discussed above to track nicely in reasonable conditions. But, a robust following sea will drive you nuts at 8k. And, plan on docking on the sticks for the most part - runs out of rudder authority rapidly with decreasing speed. Ditto on engine room - tighter than I prefer.

 

[Art]

In calm waters I love to easily pilot our 1977 34' Tolly... at any slow or fast speed. She tracks very well and responds quickly to steering wheel turn. Often cruse her at a fairly economical 6.5 to 7 knots [7.58 is her calced hull speed]. Steers and tracks well at 4 to 5 knots too. When docking... I usually leave rudders straight and use engines' rpm with trany shifts for all maneuvers

As sea conditions become filled with slightly taller sharp peaked white caped wind-waves I like to speed up onto plane... 16 to 17 knots...scooting over them. White cap waves larger than 3' make for speed adjustment.

Following seas are a whole different matter. Ya just gotta know ya boat and how it handles in those babies. Then it can be no problem. But... if its a following sea inside battling currents with conflicting winds... well - just watch this fun video!

 

[Slowmo]

We run displacement speeds in our 40' Tollycraft burning about 4gpm at 8kn. The boat tracks just fine in a variety of seas. One thing is that our Tollycraft does have a skeg/keel. I used to run my uncle's 34' Uniflite outside the San Francisco Gate. That boat had no skeg and was a real handful in following seas at displacement speeds.

 

[tiltrider1]

We run displacement speeds in our 40' Tollycraft burning about 4gpm at 8kn. The boat tracks just fine in a variety of seas. One thing is that our Tollycraft does have a skeg/keel. I used to run my uncle's 34' Uniflite outside the San Francisco Gate. That boat had no skeg and was a real handful in following seas at displacement speeds.

These are the numbers I see with 70’s & 80’s planing hulls running slow. FD hulls usually are in the 2gpm at 7kn wich is 3.5 kts to the gallon. That is a 75% improvement over a planning hull.

One should note. Fuel cost is just about the cheapest part of owing a boat. I wouldn’t shy away from a good Uniflite or Tollycraft just because she burns more fuel than a $500,000 NordIc Tug.

 

[Art]

These are the numbers I see with 70’s & 80’s planing hulls running slow. FD hulls usually are in the 2gpm at 7kn wich is 3.5 kts to the gallon. That is a 75% improvement over a planning hull.

One should note. Fuel cost is just about the cheapest part of owing a boat. I wouldn’t shy away from a good Uniflite or Tollycraft just because she burns more fuel than a $500,000 NordIc Tug.

Well put!

 

[rslifkin]

These are the numbers I see with 70’s & 80’s planing hulls running slow. FD hulls usually are in the 2gpm at 7kn wich is 3.5 kts to the gallon. That is a 75% improvement over a planning hull.

One should note. Fuel cost is just about the cheapest part of owing a boat. I wouldn’t shy away from a good Uniflite or Tollycraft just because she burns more fuel than a $500,000 NordIc Tug.

He's getting 2 nmpg at 8 kts. I'd bet it's closer to 3 if he slows down to 7. Still a little worse than the better FD hulls out there, but not nearly as big a difference. With any hull type, slowing down a knot or so below hull speed burns a lot less fuel than running right at hull speed.

 

[Art]

He's getting 2 nmpg at 8 kts. I'd bet it's closer to 3 if he slows down to 7. Still a little worse than the better FD hulls out there, but not nearly as big a difference. With any hull type, slowing down a knot or so below hull speed burns a lot less fuel than running right at hull speed.

Very true!

 

[Nick14]

But... if its a following sea inside battling currents with conflicting winds... well - just watch this fun video!

If my wife ever sees that video, it will be the last time she goes out on a boat.

 

[ranger58sb]

Some additional data points, in case useful:

Our boat is nominally 58' but actually 60' OAL. Actually, about 5½' of that is bustle (small integrated swim platform plug big-a$$ hydraulic lift platform). Which leaves us with a hull length of 54½'.

But... our waterline length appears to be about 45½'... and that's the part that guides our hull speed calculations.

The calculator says ~6.7 kts at a factor of 1.0, and ~9.0 kts at a factor of 1.34.

Our actual fuel consumption (well, instantaneous, as displayed in our nifty electronic engine data) at 8.0-8.5 kts usually varies from 2 GPH/engine to 4 GPH/engine depending on wind, tide, current, waves, etc.

IOW, we see anywhere from 4 GPH/2+ NMPG to 8 GPH/1+ NMPG, depending.

Not truly competitive with purpose-designed hulls/engines optimized for best fuel economy.

OTOH, in our case, I think it's not a bad compromise given 1800 HP (2x900) and a comfortable 25+ KT easy cruise speed if we need to loaf along on plane for a while. For whatever reason: weather, sea states, calendar planning, etc.

-Chris

 

[Nomad Willy]

Re the Tolly-Uniflite example the OP presented there are huge differences in the two.

The Tolly should be more easily driven because of their relatively narrow chine beam.
The Uniflite in contrast has a wide chine beam and I suspect .. more weight per foot of length. This would make the Tolly a much better choice if range and fuel burn is a very important consideration. The Uniflite is not an easily driven boat. This however is not true of some early (like the 27’ cruiser) models.

Last but not least for some is that the Tolly actually looks a bit like a trawler where-as the Uniflite is pure cruiser in appearance. Varies boat to boat though.
Re personal opinion I’d rather have a Uniflite hull in a smaller (20’?) boat and a Tolly at 35-45’.

Both were huge players in the 70’s-80’s cruiser market. Both highly respected brands.

 

[Dr. Rob]

Modified trawler

I just sold my really nice Silverton 34 because it wasn't practical to run her below planing speed, and currently too expensive to do it. At hull speed she would wallow around rarely staying on course without constant corrections. Wonderful boat, but poor judgement on our part thinking we could use her like a trawler.

So...it's almost impossible to find affordable (less that $70,000) North American built boats in the trawler category. I think I've seen comments posted from Tolly and Uniflite owners stating they can throttle back without issue even though they have planing hulls.

Any helpful comments would be appreciated

I have just listed my 1985 38 ft Californian for sale . Located on the Chesapeake Bay for 59,000.00
This is a modified deadrise so you can cruise all day at lower speeds- we usually get 10 kts at 1600 rpm. She has Caterpillar 3208’s NA.
Interestingly I am doing a Sea Trial on Cruisers37 Express next week so your post caught my attention. I am not looking for using her at planing speeds a lot ,due to fuel consumption.
Good luck with your search.

 

[Nomad Willy]

Dr. Rob wrote;
“This is a modified deadrise so you can cruise all day at lower speeds-“

Interesting
What about slow speed handling is relative to deadrise?
As I recall the Californian boats have very little DR. fwd or aft. Is that part of it? I don’t think it is .. but I am interested in your angle on DR and slow speed handling.

 

[Dr. Rob]

Hi Eric, I am definitely not a naval architect and admit readily that I may have this all wrong but I assumed the "modification" was to allow more flattening aft to give more lift and therefore more speed if desired. Maybe this is more about semi-planing hulls vs. planing. As mentioned I have 3208 NA not turbo so I haven't had the experience of getting up in the 20kt range or higher in these boats.
Rob

 

[Art]

Re the Tolly-Uniflite example the OP presented there are huge differences in the two.

The Tolly should be more easily driven because of their relatively narrow chine beam.
The Uniflite in contrast has a wide chine beam and I suspect .. more weight per foot of length. This would make the Tolly a much better choice if range and fuel burn is a very important consideration. The Uniflite is not an easily driven boat. This however is not true of some early (like the 27’ cruiser) models.

Last but not least for some is that the Tolly actually looks a bit like a trawler where-as the Uniflite is pure cruiser in appearance. Varies boat to boat though.
Re personal opinion I’d rather have a Uniflite hull in a smaller (20’?) boat and a Tolly at 35-45’.

Both were huge players in the 70’s-80’s cruiser market. Both highly respected brands.

Eric - I've owned both makes at same time. Still own the Tolly.

1973 Uni 31' sedan w/ fly bridge, twin 350 cid Chris Craft gassers. Great boat! Fast cruiser. Easy to handle. I called it our go cart!

1977 Tolly 34' tri cabin w/ fly bridge, twin 350 cid Mercruiser gassers. Wonderful boat!! Good for below hull-speeds and for full plane cruising. Handles easy as a big size pick up truck. Much more comfortable inside and out. We named it "The Office"

Both boats easy to maintain. Like our Tolly best... overall.

 

[Mischief]

I have a 37 foot Uniflite Coastal Cruiser. Twin Lehman 120 hp for power. We cruise about 1850 rpm, doing around 8.5 knts. The burn rate us just over 3 GPH at that speed. She has a hull shape much like a Trawler, can be a bit interesting in a following sea, Top speed around 12+, at max throttle, Digs a pretty fair hhole aft at that setting.

 

[Nomad Willy]

Hi Eric, I am definitely not a naval architect and admit readily that I may have this all wrong but I assumed the "modification" was to allow more flattening aft to give more lift and therefore more speed if desired. Maybe this is more about semi-planing hulls vs. planing. As mentioned I have 3208 NA not turbo so I haven't had the experience of getting up in the 20kt range or higher in these boats.
Rob

Dr. Rob,
Thanks Rob.
Shucks I was hop’in you waz an NA.
“flattening aft” … and deep fore-foot? Flat aft section won’t lift w/o angle of attack. But it probably prevents squatting. Sheer hull volume. And it’s not unusual to see trawlers w bow down. Wide flat bottom aft it easily supports the hull but pointy end .. not so much. Perhaps that’s why often you’ll find big fuel tanks aft. A little “squat” could be golden. The road to speed, but of course one would need power. Most have twin engines that make them over powered to do 7 knots and underpowered to do 10. But people keep pack’in more stuff (much of it heavy) aboard.
Thanks for getting me think’in bout those flat sterns.

 

[Finnegus]

I have a 37' Roughwater that cruises on plane at 2100 RPM at 16 knots at 10 gph. We mostly cruise at -8 knots, 1200 RPM which burns 3 gph. The boat handles great at that speed. We do a lot of our crusing on the ocean and the only difference as far as performance is that the boat rolls more in quartering seas or beam seas at low speed. This photo shows the bottom profile. It was taken before our repower. We have larger 4 blade props now. The RW does have a keel and with the sharp entry and relatively narrow beam tracks straight at all speeds. It is a Ed Monk jr design.

 

[Nomad Willy]

Mischief,
I was working at Uniflite under Keith Walton during the design period for the C37.
I left before the C37 hatched but I recall power was small Volvo 4 cyl. gas engines. Well aft (as I recall) but engines being small they were also light.

Don’t remember the speed targets but we tested the first plug on Bellingham Bay and she was definitely planing. Don’t recall the power at all. Probably was one V8. Maybe one V8 was considered to be equivalent to the two Volvo 4’s. ? But ballasting was done and I wish I was more involved in that program.
My 28’ OB was the chase boat/camera boat used mostly to gauge angle of attack.