Gulfstream 28X Reduced

[fallguy1000]

You need to think like a designer a bit. A designer may not like the idea and say no to it.

Consider how often Mertens faces people wanting to tweak his designs. It is a weekly event. Does he have a mandate to explain to each of them his reasons for not modifying every design 20" on length and 9" on the beam? Hardly. Many of them are tire kicking only.

I think you are asking, but it is a bit unfair. All kinds of things happen when boats are made more narrow. If they have a hardtop; they can become more unstable in turns. Or people still want a big hardtop on a now smaller boat.

And, after a point, for the designer, it starts to sound like the runaround. Now, I am hopeful you would build one of Merten's designs, so hoping I am not out of bounds here commenting.

But I do think you owe him some grace. A designer has a right to answer that he doesn't like the idea.

Most boat design/builds need to follow a buyer's statement of requirements. If you provide a sor, the designer can put you on the right boat and tweaks are not needed. Mertens has a pretty good variety.

If you provide the sor, then a designer can point and say this is the best plan for you. No lofting required.

[cape_fisherman]

Jacques has repeatedly said that ALL dimensions, not just length, must be scaled.

I'm fairly sure the tutorial written by Jacques says linear scaling can be acceptable.

[Chessie]

No offense meant at all to Jacques only the utmost respect.

If Jacques has a desire to keep the original design intact with no modification, I fully respect that.

I’m looking for an efficient boat that runs with minimal HP, can run 40-60 offshore, 1-2 times a year on very select days in the hands of an experienced skipper. Otherwise the need is an inshore/ large tidal bay or river boat but one that still runs with maximum efficiency with minimal HP.

That is the Panga 25 as described here and why it is my short list and targeted build.

Based on what is published on this website about scaling, there should be no reason the GS28 can’t be done if done properly as detailed in the article about scaling. The overall proportions would be the same as the Panga however it does have more volume.

I’m being told the scaling can’t be done and I am just trying to understand why. It’s not meant to be offensive, just trying to understand the issues with it. I didn’t know asking “why” was wrong or could be construed as inappropriate, definitely not intended as such.

Chris

[fallguy1000]

No offense meant at all to Jacques only the utmost respect.

If Jacques has a desire to keep the original design intact with no modification, I fully respect that.

I’m looking for an efficient boat that runs with minimal HP, can run 40-60 offshore, 1-2 times a year on very select days in the hands of an experienced skipper. Otherwise the need is an inshore/ large tidal bay or river boat but one that still runs with maximum efficiency with minimal HP.

That is the Panga 25 as described here and why it is my short list and targeted build.

Based on what is published on this website about scaling, there should be no reason the GS28 can’t be done if done properly as detailed in the article about scaling. The overall proportions would be the same as the Panga however it does have more volume.

I’m being told the scaling can’t be done and I am just trying to understand why. It’s not meant to be offensive, just trying to understand the issues with it. I didn’t know asking “why” was wrong or could be construed as inappropriate, definitely not intended as such.

Chris

You would forever regret reducing the beam of the GS.

The boat will rock more at drifts. Be smaller for little or no gain in performance. Be a touch more unstable in turns, lower ppi, lower displacement.

I apologize for my tone. Why would you want to reduce the beam of an already pretty narrow boat? Perhaps it isn't about whether you can or more whether you ought?

[TomW1]

Chris I am not sure why Jacques said no to down scaling the GS28, as the designer he is the expert and knows what he is talking about. If I were you I would go with the Panga 25S and I believe it can use a motor bracket by moving the console forward a foot or so, the batteries and fuel forward you can offset the weight of the motor being moved back on the bracket. Moving a Yamaha 90 or 115HP motor back affects the boat by requiring you to move weight of an equivalent of roughly 700lbs forward of where the original rear of the console was. So 70lbs moved 10 feet forwards would do it.

Well good luck, which ever boat you end up.

Tom

[Fuzz]

Fallguy makes a very good point. Something I learned in my former life is after asking is this something that can be done you should always ask is this something that SHOULD be done. We all by nature want to say heck yes I can do that. But when looking and asking is this really a good move the answer can be NO. Just my 2 cents worth from the peanut gallery.

[Chessie]

Yes the Panga 25S would be the selected option.

Not sure I would regret reducing it since it would be the same overall size as the Panga, but still “bigger”. Yes, due to the V it will rock more. Trust me I currently have a 1987 Wellcraft V20 (Awesome Boat) but she will rock you with that 20 degree angle.

Fallguy no offense taken, whatsoever.

In addition, I also have a 1970 Boston Whaler 13’ Sport so I have an appreciation for variations of hull design and have run everything from my 2 kayaks up through 25’ Classic Makos to flat bottomed Carolina Skiffs skiffs in every conceivable water type from swamp to open ocean.

Just odd in my neanderthal brain, that the Panga 25 can be scaled up (Confirmed in another thread) but the GS28 can’t be reduced when overall dimensions are within inches of each other.

I’ll stick with the PG25S and appreciate the input.
It’s also the somewhat easier and cheaper build which is also part of the equation.

Again, much appreciated guys!!!!

[Chessie]

viewtopic.php?f=2&t=30476&p=284542&hilit=Gs28#p284542

I was doing some more reading, I SPEND ALOT OF TIME READING HERE, and stumbled across this old thread and because nothing in here says “no” it would appear that the GS 28 is OK to be reduced in length only to 26’.

Now I’m even more confused as I thought one dimensional scaling was not recommended.

This is why I ask the explanation questions and only because of this.

[fallguy1000]

viewtopic.php?f=2&t=30476&p=284542&hilit=Gs28#p284542

I was doing some more reading, I SPEND ALOT OF TIME READING HERE, and stumbled across this old thread and because nothing in here says “no” it would appear that the GS 28 is OK to be reduced in length only to 26’.

Now I’m even more confused as I thought one dimensional scaling was not recommended.

This is why I ask the explanation questions and only because of this.

Most likely; the one dimensional change is allowed because the last section is all the same or close. So, you take out one frame and can fair the change. Or, all the frames can be moved in 2", etc.(Without reading)

Keep in mind, shrinking a boat requires making the plywood of a dev hull turn sharper faster. And the designer is not eager to suggest it can be done if it might become trouble at build.

But the GS26 sounds really cool. If we do move to Texas. Mrs. Fall doesn't know it, but I am gonna make a bay boat and the GS26 could be it, although I like the Abaco23 as well. My only issue is any boat I build needs a head. My days of bucket use are ending and it is hard for the ladies as well and I like having them along.

[Chessie]

That explanation would make sense to me and would still open up the other possibilities that I was originally looking for!!!

If true, this will be confirmed before I pull the trigger.