Need a list of under 40' full displacement boats

The Maple Bay series - 27', 30', and 32' were marketed as as slow cruisers. I'm not going to try to suggest they were FD or SD hulls as so far I've been very wrong in my assessments. But nice little coastal cruisers they were. I only have photos of the 32. (The info says they are FD.)

Conrad said:

That shows the hull in about the same way as the profile drawing I have does.

Yes, better!

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Here is the profile...

I should not do this, but I will give my experience on a couple boats. Last year I was on a Grand Banks 32 with the standard 120 HP six cylinder Lehman diesel. When giving it full throttle I could feel the bow rising up. A year or so before that I was on a Krogen 42 with a single engine also and I think the same engine. When at full throttle the bow seemed to plow and "dig it", but did not attempt to rise up.

I am not saying I know this does this or this does that, but I am relaying my personal experience on these two boats.

Conrad good profile of the E32 and it looks FD. The aft bottom has a shallow buttock line but it rises all the way up to the WL. FD.

I remember the Maple Bay and definitely recall them as FD. Saw one at Point Baker in SE AK several years ago. They liked my W30 and I admired the MB. The ones I've seen were the 27 and 30'. They were powered by very small Yanmars.

bikeandboat,
I used to think hull speed was attained when the bow started to rise on a FD hulled boat. I discovered years later it happens well before that. I suspect that on most FD boats boats and on a lot of SD boats an excellent speed to run for economy w acceptable speed relationship ..... the point of bow rise as a good place to start looking for an ideal cruise speed. Just an opinion long in coming. Don't have any idea why the KK42 didn't "rise up". My Willard does.

psneeld said:

Now for the photo gurus...FD or SD???...what boat? For the really good...how big of an engine????

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The winner is...semi-displacement Nordic Tug 32 with 220hp

psneeld said:

The winner is...semi-displacement Nordic Tug 32 with 220hp

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Well, at least I got the manufacturer correct. Good little exercise though, as it really made me take a good look at my own bottom. Um, moving right along...

psneeld I'm amazed.

Maybe I've never seen a NT 32 out of the water. The chine is very distinctive. Much like the old Uniflite's except softer.

Was hard to tell how big the boat was. Could have been NT 26 ish or GB 42 or even bigger. The chine was the give away but I didn't (and don't) remember seeing it.

What's really funny is that I've claimed the NT32 as my favorite boat numerous times and now realize how unfamiliar I am w it. Now that I see the arched bottom and the soft chine I like the N32 even more. I like the fact that the chine has some rocker in it aft too.

Eric, you're not the only one who was challenged about the size. Here is a shot of our NT 42, and I'm certainly pressed to tell the difference.

I would've guessed 26. They all look the same.

Just for the record. The prairie 29 needs to be scrubbed from the list. It is definitely an SD hull. Square and flat aft end. Horrible in a following sea and not great in a beam sea. When Atlantic acquired the molds and called it the Atlantic 30, there were a couple equipped with twin 115hp Volvos and they would achieve plane.

Thanks, Bake. As an ex owner, I'm sure you'd know.

Ken Hankenson, the designer of the Eagle 32 calls it a SD hull. I have a copy of an old article were he speaks about modifying the Union Jack steel hull design for Transpacific to build the Union Jack in fiberglass.

magicbus said:

So this 38 doesn't make the list eh?

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North Baltic,
That magicbus is IMO one of the 99 per-centers. Can't call it either but if could get released from prison if I made the call I'd call it FD. I'd want a bigger rudder though. The engine must be way fwd. Is the bottom cross-section fwd concave or straight?
Your NT is a solid SD.

Al said:

SD FD? Been told we are SD by forum experts. Confirmed by builder publications as a SD. (Of course in 1978 fuel burn was an issue and speed at a fuel cost was important perhaps classified for sales pitch purposes) Now, to view bottoms in this thread that appear to be much more fair in contour encouraging higher performance being logged in as FD and that accepted by some of those same experts who judged our boat as a SD raises ones eye brow, just saying.
Happy and content to be a SD traveling on a FD agenda. 1.25 GPH at 6.5 is acceptable.
Here is the bottom of our boat. There is no flat surface the full race of the bottom. Sharp entry, moving to a round couture surface continuing to the stern as viewed.
Al

Marben Flybridge Trawler Pilothouse Pocket Cruiser

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Now I am more confused, Earlier on in the forum I submitted our hull was a FD however the above photos were deemed by forum "Experts" to reflect a SD hull. Please if you folks would, tell me how this shape identified as a SD when the Magicbus submission of a Nordic Tug and another similar hull, are rated at 99% to be FD?
.
In line with this, if the required HP to put a SD on plane is such that the end result of little increase over hull speed is obtained at a fuel burn that exceeds common sense or by the "Bow is rising", or the bulging wave action created represents friction, is not that boat demonstrating overriding FD actions??

I am satisfied to be identified as a SD given that an installed 500 HP engine would power the 'Bow Up" and create a 'Bulging Wave' action and in one ugly way, be on plane. Better and more happy knowing that hull speed of 7 knots with 85 HP at hand and not challenged, at 1.5 gallon fuel burn slipping through the water giving the appearance of a FD boat on slow cruise.

SD/FD discussions rank right up there with anchors, slanted windows, fly bridges, and such. Much to be appropriated and enjoyed in this wonderful boating forum. Thanks for the ride be it SD or FD.

PS: At the time of the photo we were powered with 58 HP. Since re powered to 85 HP.

Al-Ketchikan

Nomad Willy said:

North Baltic,
That magicbus is IMO one of the 99 per-centers. Can't call it either but if could get released from prison if I made the call I'd call it FD. I'd want a bigger rudder though. The engine must be way fwd. Is the bottom cross-section fwd concave or straight?
Your NT is a solid SD.

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Hi, Eric. Yes NT is 100% SD.

This boat is 100% FD orginal low hp engines but new egine take this boat planing boat. So the question is not only the body shape.

I absolutely love my Nordic Tug 37. Looked at the 42 and decided on the 37. Took her on a five month cruise to get her home and had no regrets. Systems on board are first class.

North Baltic sea said:

Hi, Eric. Yes NT is 100% SD.

This boat is 100% FD orginal low hp engines but new egine take this boat planing boat. So the question is not only the body shape.

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Baltic,
That's amazing that that boat can go that fast. The reason is the beam to length ratio "BLR" I have an 18' canoe that was a 20' canoe. Two feet was cut off by putting a false transom or "dam" in the mold 2' up from the stern. Done at the factory (Clipper). With a 6hp OB the canoe makes planing speeds. Wind in the face canoeing. On the other end of the LBR there was a guy on the Willard Boat Owners Group on yahoo that put an 80hp engine in his W30 and achieved a speed of 8 knots. The wake was (as the kids say) awsome.

But re the boat above in the vid the speed you see is/was not earned efficiently. If a more typical speed hull (straight runs aft) was employed on the vid boat the speed displayed could have been achieved w much less power.

Nomad Willy said:

Baltic,
That's amazing that that boat can go that fast. The reason is the beam to length ratio "BLR" I have an 18' canoe that was a 20' canoe. Two feet was cut off by putting a false transom or "dam" in the mold 2' up from the stern. Done at the factory (Clipper). With a 6hp OB the canoe makes planing speeds. Wind in the face canoeing. On the other end of the LBR there was a guy on the Willard Boat Owners Group on yahoo that put an 80hp engine in his W30 and achieved a speed of 8 knots. The wake was (as the kids say) awsome.

But re the boat above in the vid the speed you see is/was not earned efficiently. If a more typical speed hull (straight runs aft) was employed on the vid boat the speed displayed could have been achieved w much less power.

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This typical Finish boat fd hull 10,5 m leght and 2,7m bred max speed 16 knots and engine ford 590E 106hp86kw building 1970



https://youtu.be/6HHC5HS0dpg


You can see this video, boat hull is full displacemen and she can cruising 16 knots

So?

Oh I see. You're trying to show I'm wrong because a normal LBR hull can plane too.
There's got to be a reason and I don't know what it is. A big part of it is light weight. Can't see the stern and it could have a anti squat board aft a little like the V shaped things they put on the cavitation plate of outboards. Really can't make judgement on planing ability w/o seeing afterplane of the hull. And of course cruising speed is not the "working speed" of this boat. And lastly (for now) this boat is not planing.

If the boat usually runs 16 knots it's got the wrong hull.

Re the Majicbus ...
My labeling it a 99 percenter was a bad description.

I will better that by saying ....
For all practical purposes it's definitely is a FD hull but has at least one characteristic of a planing hull. So technically a case could be made for it being SD.

Hey Eric, just because it can do planing speeds does not mean it is planing. A Hobie cat can do 20knots....those hulls are not planing. There are big cats like the PDQ. If I remember correctly, are not planing hulls but those cats do planing speeds. As to the physical scientific explanation, I have no clue. I even read an article trying to explain it but I either don't remember it or it didn't stick...basically did not understand it so I could not get it to stick in my brain.

John,
Yes ... But usually a boat that looks like the one in the pic w a normal aspect ratio would be very bow high at the speed we see in the pic. I still suspect there is a planing board at the stern or some other irregularity.
In one of the Atkin design boats there is a 26' V bottom boat w almost the same rocker as a FD boat but 18 knots is stated for speed. No gimicks there for sure.

I applaud Eric for re-raising this subject. Maybe 21st sail boat hull design is instructive for this discussion

The fastest mono hull sail boats of the past generation or two all have a flat "nearly"submerged transom and the ability to safely surf at 25 knots. A few years ago we attended a Volvo Ocean Racing pit stop in NZ. Those hulls do not fit in any way shape or form fit into a classic FD sail boat definition. Many gentrified versions of this hull design are on the market with less adventuresome goals.

There is no longer the need to say a FD is only this or a SD is only that for modern efficient cruising power boats of this era. One look at the back of a generally agreed FD hull like a Nordhavn or Selene says the same. Or studying the realities of a Dashew FPB.

Tad Roberts pretty well summarized this whole subject a year or so ago on TF. Re-posting that or making it a sticky would be worthwhile.