Troller Yachts vs Trawler Yachts

I presume most are talking of "power boats at displacement speed", - so why the added ballast?

- My boat cruises at 10 knots is very stable and does very nicely in most seas - and if my passage is not running with a big swell - I sneak up a creek, tie off to some mangroves and wait for a weather-window then continue my journey...
- Visibility is not nice when squalls and rain are blown at 30 to 40 knots, but anchored up, and the bridle set, it becomes quite comfortable facing the 'roar' of the gusts...
- At present I am on hard stand at Monties but with existing tanks full (1300litres) I have a range at 10knots of 2000 nautical miles... http://www.boatdesign.net/forums/boat-building/my-little-piece-peace-25962-142.html#post552093

 

Fascinating thread. The quest for efficiency under power has been nigling away for many years. I think William Bebe’s book was perhaps the first influential treatise on the subject, it was for me at least. Prior to reading this, i didn't think any pleasure type power boat could be economical, let alone cross oceans. He certainly proposed lighter displacement, and lower top hamper than was ‘normal’ prior to his designs. He always included some fixed ballast in his designs, mostly to allow higher top hamper (i think) and lower metacentric height.
Tad Roberts must be the current master, certainly his ‘box keel’ boats show excellent economy by combining a long (hydraulically) thin hull with sufficient WL beam to give reasonable static stability. Bolger did some similar boats.

My own experience at deep ocean work under power has mostly been in deep keel sailboats, so the heavy keel was a significant influence. Slightly slack bilges meant a fairly easy, if extreme, motion in the NW pacific. The few occasions i have been on un-ballasted boats in such conditions, the motion in roll and pitch was pretty violent, and quick, and very tiring. The ‘sail’ boats were all very hard bilge, in one case a ‘Barge Yacht”, in another a single chine with the CB up, and the ‘power boats’ were all variations on the shallow “V”, hard chine, semi planing, style with a “Troller” or “Tug” topside. None had ‘flopper stoppers’ or stabilization. I knoe Bebe proposed slack bilges, and floper stoppers for his boats, but i assume the ‘flopper stoppers’ are a pain to handle most of the time.

My question is, is it possible to design a light(ish) power boat with good economy without ballast, and without ‘flopper stoppers” without going to the extreme of, say, Wind Horse. The other extreme, a trimaran, like “earth race” are not to my taste. I once ‘designed’ a trimaran, which was built, and a bit of a disaster, being very violent in its motion, but very fast.
My preference would be in the 40’ range, single engine, perhaps just a stretched version of Bolgers boat in Tads post #75? Equally, perhaps i should be satisfied with Tad’s Lite 39, or even Beuhlers Pilgrim 44. I think what i am thinking of is Tad’s lite 39 with hard chines and a box keel for the engine, no flying bridge, and the engine and tanks under the bridge floor. Having the engine IN the galley cupboards sounds loud, even if the underfloor installation is not much better. My experience so far has been for the need for COMPLETE gas sealing of the engine room from the accommodation, and serious sealed ventilation of the engine room from on deck, the further aft the better. Otherwise its like living in the engine room for a few days at a time.

 

Some sort of stabilization would be desired if the boat were going in Blue water.

I have often thought a very wide centerboard trunk could be fitted with a board that could be driven to create the same stability as fins with out the dangers.

The board would of course pivot up on grounding and not breakaway or knock a hole in the boat.

The Herrishoff Marco Polo concept , 6-1 or better LB ratio , but with a smaller lighter diesel working at 75% ot 80% of rated power would have best fuel burn.

The big hassle for most folks is a long skinny boat costs more to dock than a short fat pig 3 stories high . And for most the dock costs are far higher than a seasonal fuel bill.

 

I was looking for a referenced I posted long ago, a fishing trawler conversion for cruising Asia, but I do not know where it is at the moment. I did find this somewhat similar looking vessel
http://www.boatdesign.net/forums/powerboats/searching-fuel-efficient-powerboat-37835-10.html

I'll keep looking for that other reference.

Meantime you might have a look thru this subject thread about a Pilgrim redesign effort
http://www.trawlerforum.com/forums/s3/redesigning-pilgrim-40-trawler-canal-boat-11212.html
I imagine you could place a box keel on the bottom of a hard chine version if you so desired.
http://www.trawlerforum.com/forums/showpost.php?p=190475&postcount=221

 

@Sailor Alan:

Have you considered one of George Buehler's designs called the Diesel Duck? The Seahorse Marine Diesel Duck 382 is within the length you specified and they are proven passagemakers that sip fuel. It's not in the "light (ish)" category of boats but it's sure is a sweet little ship. Here's a link that you might find interesting: http://www.dieselducks.com/Seahorse ducks.html

 

Diesel Duck

Have you considered one of George Buehler's designs called the Diesel Duck? The Seahorse Marine Diesel Duck 382 is within the length you specified and they are proven passagemakers that sip fuel. It's not in the "light (ish)" category of boats but it's sure is a sweet little ship. (quote)

Thank you for the sugestion.
I admire George Buehler and his designs greatly. His Pilgrim 44 would be #1 on my list, though i would change the cabin a bit. I would consider reducing the shear a bit, and moving the main cabin sides to the gunwale. I would try to fit a “W” shaped couch like a pool lounger in the pilot house for a watch keeper/visitor. This is a very light boat, and really ticks all my boxes.

I greatly admire the interior of his new Diesel Duck 34, and might consider this with a ‘sugar scoop stern, though i think its quite fine as is, and docking costs less. As you say, the “Ducks’ are on the heavy side and this is good and bad. The good being a smooth soft ride in weather, and a usually slow comfortable roll rate, The bad being cost, you tend to buy boats by the pound. I thinks its going to be a pilgrim 44 after all.

 

It would be awesome to see "Pilgrim" built. If remembered correctly it has about 10-12" deck sides and would say they should stay that way. Keep the sheer as is it looks great and maybe add about 2' at pilot house for laying down.

 

Should it be considered ironic that a beamier, heavy boat with better accommodations for her length and which costs relatively less to dock may be too expensive to go far from said dock while a relatively narrow and light boat (accommodations a bit smaller, less flashy) may be economical to cruise but boy are they gonna get you in docking fees if you stand still for long?

 

Perhaps if you could build it really quick and dirty of found material and throw a clapped out volvo MD3 in her it might make a bit of sense. If you just wanted to do coastal cruising. But I doubt it. Reality (for most of us) is that it's really expensive to build new, even simple new.

There is no way you can build 44' by 10' boat with heavy plywood structure like this at 11,000 pounds. More like 15-16,000 pounds if you are careful. Even at only $5.00 a pound for materials that's $75k, with no tools or overhead. And when finished she will only be worth $35k at best.

When there are lots of perfectly good retired trollers for sale at $10-20k building new ends up throwing money away.

And do not take George's HP/fuel/speed figures at all seriously. If you could build a Pilgrim 44 at 16,000 pounds, it will require (at least) 6.5HP for 6.5 knots, about 10HP for 7 knots, and 14HP for 7.5 knots. That's HP at the prop, assuming proper shaft speed and propeller for the speed, clean bottom, no wind or sea (actually calm requires a tailwind).

Something like an old Perkins 4-107 with 2.5:1 gear would do okay in a boat like this. Figure on 7.5 knots max and .75usg per hour.

 

>may be economical to cruise but boy are they gonna get you in docking fees if you stand still for long?<

That is why they invented ANCHORS!

Living on a boat , usually as a dockside fully hooked up cottage is a fine hobby. BUT it has zero to do with cruising.

A cruising boat may need to dock for fuel, perhaps water or waste dump , but thats about it.

The box keel concept, if built properly, is interesting as it would allow the cruiser to take the ground near shore for extended periods.
Much as British sail boats did with bilge keels.

If cruising requires a pool , tennis court , petting zoo, and bar with great food , a marina might be easier esp if the boat can only live off a power pole.

>So, the question - for most people - is whether they buy a fat 40 footer that does 2mpg, but which enjoys a comfortable, almost home-like interior. Or a slender 50 footer, with its higher associated build and berthing costs, that does say 4mpg.<

Boats are for the most part created by the pound , so if the 50fter is lighter (without exotic construction) it might be cheaper to create as well as operate..

Dirt House stuff , like washer, dryers , dishwasher , can be found that are light , if required for the home comforts.

 

When its all said and done the best way to find an economical cruising boat on today's market is to find a 20+ year old moderate sized FG sail boat that is in basic good shape or has been updated. The second best option is a 20+ year old fish boat that can be spiffed up at low coast. If $ is an issue stay away from large boats.

 

Puget Cruiser

Thank you Tad for your sound and sage advice.

This answer has caused us to do a critical review of our intended use of the boat, age, finances, grandchildren, and other circumstances.

As a new member, i should have done this before, but now i have read hundreds of entries from several of you, but frankly until now i didn't know where to look. As a retired designer of aircraft, lifelong sailor, and occasional boat designer, i received a considerable education.

What we really need is long, thin, light, and low power, and fairly quiet under power. We now have no need to venture outside the Puget sound proper, and i have no wish to trailer. Gig Harbor roads are very steep, and have tight turns. Mooring would be in semi-sheltered open water in summer, possibly beached in winter (hence outboards).

Accommodation could be summarized now as; two perminant bunks/double for adults/grandkids (wife refuses to ‘make up’ beds each night), fold down/convertible double for occasional adults, stand up toilet room (changing grand-babies), double burner cook top, sink, and not much else. The cooler and table could be in the cockpit.

I like the warped deadrise hulls, nearly vertical bottom bow skin (like our old plywood Cherub class), transitioning to 5deg stern @ 36’-40’ long on a 8.5’ beam, ~12kt full speed, and near vertical stem might be satisfactory. The long waterline, and narrow taper allowing it to ‘run’ reasonably level. Looking a bit like a Chesapeake ‘deadrise’ hull, perhaps even with the ‘drake tail’ with a ‘sail drive’ under it.

I cartooned what i think i had in mind some years ago, in Catia, though i think this is only 35' long.

We will explore the possibility of used vessels, especially re-powering such. There seem to be a lot of old stern drive vessels with the stern drive missing, ripe for outboard re-powering, but most are very heavy, and manny are very wide as well.

 

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