What is going on here? 740hp 30 mph Gulfsar Trawler??

[MurrayM]

No, it is a displacement hull, only very slightly modified from the sailboat hull. 740 hp on a boat like that is an idiotic waste.

What does this guy think he is going to do? Go water-skiing behind his trawler!?! Obviously someone who has more dollars than sense.

Hey! Maybe if you added some Calkins Bartender type fins (just below water level, starting amidships and getting wider towards the stern) would get this puppy scooting along like a surf scoter trying to take off

 

[Ski in NC]

You never really know what hull shapes do when adding power.

This hull shares at least some shape details with Downeast lobster boats, but they tend to have a lot of flat from the transom at least somewhat fwd.

I've run a bunch of DE hulls and some scooted nicely with modest power at 17-odd kts.

One 36 had a 500hp C9 Cat in it, stood nose up and plowed, did not run worth a crap. Out of the water its hull shape did not seem much different than the ones that ran well.

Never can tell for sure just looking at hulls. Maybe NA's can, but not this gear head.

 

[MurrayM]

I'm sure shaft angle comes more into play as power is added. Our arse just squats at higher rpm.

 

[Art]

I'm sure shaft angle comes more into play as power is added. Our arse just squats at higher rpm.

Floating through [i.e. into] the water is not the same as skimming over [i.e. a top] the water. Thus, full displacement and full planing hull designs' intended functions and use capabilities.

Shaft angle could play some effect on angle of any type hull in the water at various speeds. However the slightest angle adjustments in bottom contour could at least somewhat overcome a specific shaft angle. Trim tabs [when considering their miniscule sq. inches as compared to a hull's massive sq. inches] directly represent this factor. I.e., by what a severe effect trim tabs exert on hull trajectory with just an inch or so of their upward or downward angle change. So, then, think of what effect the slightest angle alteration in a hull form would effect on hull trajectory position in water.

I'll leave the morph of semi displacement hulls alone for this post - although there was a great 38' SD woodie in our family during the mid 60's through late 70's. It was a good performer regarding its intended hull design capabilities.

 

[RichHurst]

If you looked at the pictures and read the narrative, anyone notice one of the heads non-functional, no mattress on the aft bunk, some wrap around an engine hose, and I'll bet a host of other malfunctioning equipment. I'm just imagining the smell in the bilge.

 

[rsn48]

My guess is it does not run very well at 20+ kts. Either squirrelly or super bow high.

At higher speeds above displacement speeds, the boat probably tracks true as an arrow, below displacement speeds, it might be squirrelly. The faster forward motion will keep it on a straight track, at low speeds not so much.

Bow high, depends on whether the boat has effective trim tabs. With a stern drive, such as my boat, you can trim the bow down. Trim tabs can assist in lowering the bow.

For me, the one negative is that solid flybridge cover, it brings the center of the gravity higher and that boat must be a rock and roll champ in a beam wind.

 

[FF]

"For me, the one negative is that solid flybridge cover, it brings the center of the gravity higher and that boat must be a rock and roll champ in a beam wind."


Perhaps , fishermen on the Grand Banks would hoist an anchor up the foremast to slow the roll and ease the roll reversal.

 

[PM]

Sure, it's a nice boat. The condition looks to be about average, the cost is certainly dictated by the cost of the replacement engines.

But, I must take exception to the statement "you can make anything fast by adding enough power" Simply not true. There comes a point that the hull design will pull the boat under the water at a certain speed. A displacement hull shape is not a lot unlike an airplane wing. Instead of air moving faster over the bulge of the wing causing lift, water running faster under the hull causes suction. First you get a bigger bow wake, then your waterline goes down deeper and eventually a boat becomes unstable and goes under.

pete

 

[CharlieJ]

This boat is a Gulfstar motor sailor hull with a shorter keel. There is nothing “semi-displacement” about its hull form. It can be driven at hull speed with only one of its two Perkins 130 hp engines on line at about ¾ throttle.

Agree w/all negative comments regarding this conversion.

 

[Blissboat]

This boat is a Gulfstar motor sailor hull with a shorter keel. There is nothing “semi-displacement” about its hull form. It can be driven at hull speed with only one of its two Perkins 130 hp engines on line at about ¾ throttle.

Agree w/all negative comments regarding this conversion.

You're right - I had forgotten (thankfully) that 1970s line of Gulfstar motorsailers. The least handsome yachts ever to pop out of a Gulfstar mold, in my opinion, meaning no offense to anyone who still owns one. I guess they had a lot of room below.

 

[oscar]

You can make anything fast with a big enough motor.

Eh, no. You need a hull shape that allows getting over/on top of the bow wave and plane. You can put 1000 horse in a 40' displacement trawler it's gonna do hull speed or slightly over. All you're going to be doing is make a lot of smoke.


The other question I have here is whether the drive train was upgraded, ie prop shaft diameters, shaft logs, struts...... that's a lot of torque to carry to the props.

 

[rsn48]

In the aircraft crowd, you will often hear: "They can make a barn fly if the motor is large enough!"

 

[Brisyboy]

In the aircraft crowd, you will often hear: "They can make a barn fly if the motor is large enough!"

Wasn`t said by a Boeing engineer by any chance who worked on the Max?

 

[FF]

"Wasn`t said by a Boeing engineer by any chance who worked on the Max?"

No, Boeing competes with Air Bust so has to make aircraft that can easily be operated by very low time operators.

The equipment that caused the operators to fail to control the aircraft was not needed for an experienced pilot .