Donsan
Guru
- Joined
- Jul 6, 2014
- Messages
- 2,300
- Location
- United States
- Vessel Name
- No Mo Trawla
- Vessel Make
- Hurricane SS188
Just wait around for the next recession. There will be plenty of boats then.
Are there any "full displacement hull" trawlers out there?
- Thread starter kurt.reynolds
- Start date
The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
Just wait around for the next recession. There will be plenty of boats then.
RT Firefly
Enigma
Greetings,
Mr. kr. Nope, don't wait until the next recession and DON'T get discouraged. This is a fun, fun, fun time. I'm not going to review the whole thread but do you have a buyer's broker yet? If it hasn't been suggested, get one. A good broker will work on your behalf and possibly find YOUR boat. If you find one you're interested in, they can and should make the initial call and quiz the selling broker about the sale. I think a broker calling a broker adds a bit of seriousness to the inquiry as opposed to maybe a "tire kicker" whom the selling broker may not take seriously.
Won't cost you $.01.
Tucker Fallon helped us immensely when we purchased several years ago. http://www.trawlerforum.com/forums/members/yachtbrokerguy-1536.html
Mr. kr. Nope, don't wait until the next recession and DON'T get discouraged. This is a fun, fun, fun time. I'm not going to review the whole thread but do you have a buyer's broker yet? If it hasn't been suggested, get one. A good broker will work on your behalf and possibly find YOUR boat. If you find one you're interested in, they can and should make the initial call and quiz the selling broker about the sale. I think a broker calling a broker adds a bit of seriousness to the inquiry as opposed to maybe a "tire kicker" whom the selling broker may not take seriously.
Won't cost you $.01.
Tucker Fallon helped us immensely when we purchased several years ago. http://www.trawlerforum.com/forums/members/yachtbrokerguy-1536.html
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cool beans
Senior Member
Old 70's Gulfstar 36's and 43's are built on the motorsailer hull and have a long keel and full, round bilges. The 44' motorcruiser has the same under water profile as well. The later 44' motoryacht went to a hard chine SD hull.
Or convert an old, heavy sailboat like Winnie the Pooh:
Winnie the Pooh, sailboat to trawler conversion - Trawlers & Trawlering
Or convert an old, heavy sailboat like Winnie the Pooh:
Winnie the Pooh, sailboat to trawler conversion - Trawlers & Trawlering
FF
Guru
- Joined
- Oct 12, 2007
- Messages
- 22,552
"The square corners and flat bottom aft is what ruins seaworthyness w SD trawlers. Not to mention the small rudders."
"It is also what ruins fuel efficiency!"
YES but at 3 gph dragging a few tons of water with the immersed stern of a SD at the trawler crawl or
going better with FD might mean dropping to 2 GPH ,
a big deal if crossing the blue water , but nothing much for an inshore boating season.
"It is also what ruins fuel efficiency!"
YES but at 3 gph dragging a few tons of water with the immersed stern of a SD at the trawler crawl or
going better with FD might mean dropping to 2 GPH ,
a big deal if crossing the blue water , but nothing much for an inshore boating season.
Exactly!
Also, running a knot or just a tad more below hull speed makes even SD and P hulls run darn efficiently, fuel usage wise... regarding the broad scope of things on boat costs while owning/cruising.
Nomad Willy
Guru
But Art since this is about FD I will add .......
The FD hull is shaped to fit nicely on the face of the following wave .. the one right under the stern. It not only fits nice but this fit allows the water under the boat to flow smoothly and gracefully boak to it's original state before the boat came along pushing it down and to the side.
Look back in historical pictures and before engines you will not see ANY other than FD hulls. There was not enough power in sails to exceed hull speed so there was no point in building and designing boats to attain much less exceed hull speed. So boats were designed to make the best of the way water moves around and under boats.
The FD hull not only allows the water to flow smoothly around a hull but at speeds a bit under hull speed the following wave is slightly ahead of the stern of the boat. And since the stern is shaped much like the wave it can, to some degree surf down the face of the wave thereby actually pushing the bow into the sea ahead. Kind of like a turbocharger helping to push the intake air into the engine the energy of the following wave helps push the boat forward. That energy of course is made by the bow pushing water down and aside. And Art that energy is almost totally lost on the typical SD or planing hull. There is probably some but it must over come the huge drag of the submerged transom. Look over the stern of your boat at 7 knots. You will see a wide area of water that is jumping up and down frothing in a mass of energy released by the transom stern and created by the bow/propeller/engine. Mostly lost.
So the turbulence of the large submerged transom of the SD or planing hull is not the only reason FD boats are far ahead of others in slow speed efficiency. The FD hull not only has very low drag it reclaims some of the energy lost pushing the sea down and aside.
Due to their length many ships are designed to take advantage of the second following wave made by the ships bow. Some like a great lakes ore ship may take advantage of the 4th or 5th wave back. They do this of course by adjusting their speed so the wave under the stern is slightly ahead .. of the stern. And we w trawlers do the same by adjusting our speed to adjust the position of the following wave to a tad ahead of the stern ..... one knot below hull speed typically.
The FD hull is shaped to fit nicely on the face of the following wave .. the one right under the stern. It not only fits nice but this fit allows the water under the boat to flow smoothly and gracefully boak to it's original state before the boat came along pushing it down and to the side.
Look back in historical pictures and before engines you will not see ANY other than FD hulls. There was not enough power in sails to exceed hull speed so there was no point in building and designing boats to attain much less exceed hull speed. So boats were designed to make the best of the way water moves around and under boats.
The FD hull not only allows the water to flow smoothly around a hull but at speeds a bit under hull speed the following wave is slightly ahead of the stern of the boat. And since the stern is shaped much like the wave it can, to some degree surf down the face of the wave thereby actually pushing the bow into the sea ahead. Kind of like a turbocharger helping to push the intake air into the engine the energy of the following wave helps push the boat forward. That energy of course is made by the bow pushing water down and aside. And Art that energy is almost totally lost on the typical SD or planing hull. There is probably some but it must over come the huge drag of the submerged transom. Look over the stern of your boat at 7 knots. You will see a wide area of water that is jumping up and down frothing in a mass of energy released by the transom stern and created by the bow/propeller/engine. Mostly lost.
So the turbulence of the large submerged transom of the SD or planing hull is not the only reason FD boats are far ahead of others in slow speed efficiency. The FD hull not only has very low drag it reclaims some of the energy lost pushing the sea down and aside.
Due to their length many ships are designed to take advantage of the second following wave made by the ships bow. Some like a great lakes ore ship may take advantage of the 4th or 5th wave back. They do this of course by adjusting their speed so the wave under the stern is slightly ahead .. of the stern. And we w trawlers do the same by adjusting our speed to adjust the position of the following wave to a tad ahead of the stern ..... one knot below hull speed typically.
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I fully agree with you Eric... i.e. that in general, for cruising just below hull speed, that FD hull shapes simply can't be beat, especially in the case of following seas and for overall fuel efficiency. However, if a boat owner wants to also be able to go relatively fast [let's say 2 to 3 times the speed of a same length FD boat] then an SD or P hull makes plenty sense. Also - at below hull speed the SD and P hulls do become relatively efficient regarding fuel usage. Not as efficient as FD hull by maybe 10 to 20% reduced efficiency... but as someone else conjectured in this thread... Using a gallon or two more per hour means not too much more money in the overall annual budget of boating... especially if you only put 100 to 200 hours a year on engine use at below hull speed.
In regard to following seas: Decades ago I piloted FD, SD and P hulls through following sea conditions; in inlets it can get pretty hairy with rollers coming in from Atlantic ocean that are further riled up [at times capping] due to conflicting directions of winds and currents. You are correct that the rounded aft-bottom design of FD hull does let the following sea waves roll fairly easily under the boat as the waves travel faster than the FD hull can move through the water's surface. And, tendency to broach in these conditions is lessened due to rounded stern at and below water level in FD hulls. However, in defense of SD and P hulls in following seas. I found that by using correct throttle adjustments for needing added speed through water surface the Captain can keep the faster than FD hull designs well positioned to stay just slightly ahead of the following sea's wave movements. Therefore not having the following sea wave moving from stern of boat to bow but rather to have boat consistently creeping forward into the next wave in front. There are many complications that get created by following seas, no matter what hull design may be involved. And, for sure... a riled up following sea is about my least liked sea condition to be piloting through, with any hull design.
Nomad Willy
Guru
Art,
Sounds like you've been there done that. Interesting that your least favorite sea is of the following variety. Often (perhaps most of the time) it can be my favorite. Motions are slow and gentle and control is easy. Well most of the time. At times aboard Willy it's just too much work turning the helm back and forth to be called easy. Then there's the wild times w the legs spread wide appart w heavy throttle frequently to make the big rudder even more effective. Eyes big looking at the next unbelievable wave comming from no man's land aft and if this wave don't get ya one will in a half hour .. or even an hour when you get really tired. But most following seas the Willard hull dos'nt even need helmwork to keep a reasonably straight course. I wonder sometimes how you guys get along w those little tinny rudders built for speed and not control.
Head seas too .... easy motion. Considerable bobing up and down kinda like a rocking horse on headseas. Of all the headseas Willy's been through she's never slamed .. not once. The only time she did something like slamming was sideways. In a very confused sea she got tossed sideways from the top of a wave into what amounted to a big hole in the water. Weightless for a moment and then slam ... On her side at the bottom of the hole that was probably shaped a bit like her chine area. There was a cracking sound like the breaking of a timber but did'nt check it out. Never found anything later either.
It's the beam seas we don't like in FD hulls. And the slow speed makes us follow them late in the day when ETA and anchor up time coincide as is often the case while traveling. More often than not however there is plenty of time to alter course 10 or 15 degrees.
As to the fuel saved by running FD it is'nt even close to black and white. If you made a scale 1-10 wheres a 10 was a planing hull and 0 was a FD hull you'd soon find you'd need 1-20 as the variations are great. SD hulls that are close to planing at 18 or 19 would probably burn about two times as much fuel as a FD. Maybe more. All the rest would fall in between. At the top in the middle or near the FD end at the bottom. Most trawlers would claim a 7 or 8 having hull shapes more like a planing hull w a big keel. Sometimes that's all that separates them. Where on the scale at either end or in between would depend of the shape of their hull .. and of course their displacement. Weight requires power and power requires fuel. And the most distinctive feature of trawlers is that they are heavy. Art your planing hull is of course off the map (of SD) but since it's much lighter than a trawler and is (I believe) narrower at the chine where it counts the Tolly will probably burn at the rate of a heavy trawler and then that gets thrown over the treetops w/o knowing at what speed. The tree tops being the unknown.
Sounds like you've been there done that. Interesting that your least favorite sea is of the following variety. Often (perhaps most of the time) it can be my favorite. Motions are slow and gentle and control is easy. Well most of the time. At times aboard Willy it's just too much work turning the helm back and forth to be called easy. Then there's the wild times w the legs spread wide appart w heavy throttle frequently to make the big rudder even more effective. Eyes big looking at the next unbelievable wave comming from no man's land aft and if this wave don't get ya one will in a half hour .. or even an hour when you get really tired. But most following seas the Willard hull dos'nt even need helmwork to keep a reasonably straight course. I wonder sometimes how you guys get along w those little tinny rudders built for speed and not control.
Head seas too .... easy motion. Considerable bobing up and down kinda like a rocking horse on headseas. Of all the headseas Willy's been through she's never slamed .. not once. The only time she did something like slamming was sideways. In a very confused sea she got tossed sideways from the top of a wave into what amounted to a big hole in the water. Weightless for a moment and then slam ... On her side at the bottom of the hole that was probably shaped a bit like her chine area. There was a cracking sound like the breaking of a timber but did'nt check it out. Never found anything later either.
It's the beam seas we don't like in FD hulls. And the slow speed makes us follow them late in the day when ETA and anchor up time coincide as is often the case while traveling. More often than not however there is plenty of time to alter course 10 or 15 degrees.
As to the fuel saved by running FD it is'nt even close to black and white. If you made a scale 1-10 wheres a 10 was a planing hull and 0 was a FD hull you'd soon find you'd need 1-20 as the variations are great. SD hulls that are close to planing at 18 or 19 would probably burn about two times as much fuel as a FD. Maybe more. All the rest would fall in between. At the top in the middle or near the FD end at the bottom. Most trawlers would claim a 7 or 8 having hull shapes more like a planing hull w a big keel. Sometimes that's all that separates them. Where on the scale at either end or in between would depend of the shape of their hull .. and of course their displacement. Weight requires power and power requires fuel. And the most distinctive feature of trawlers is that they are heavy. Art your planing hull is of course off the map (of SD) but since it's much lighter than a trawler and is (I believe) narrower at the chine where it counts the Tolly will probably burn at the rate of a heavy trawler and then that gets thrown over the treetops w/o knowing at what speed. The tree tops being the unknown.
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