Wife loves boats but hates sailing

[jrudge]

I am in the med in a 58 ft boat.

Up to a 3 is fine. 4 if you have to but you slow down. More than that forget it - it’s a leisure activity !

Direction of travel makes a big difference. There is no tide here to speak of but downwind is a lot more comfortable.

I don’t think you will find many Mobo owners heading out intentionally in a 6

 

[kashurst]

very difficult to give a definitive answer as everyone regardless of their level of experience will have a different view of ride quality when the wind picks up. No boat is perfect they are all some sort of compromise and I think the newer boats are worse rather than better as they manufacturers strive for 30kn+ and lower fuel consumption. The often used solution is a flatter bottom and blunter entry at the bow. There is nothing especially different about the solent - it's tidal and the wind speed/direction changes. You can encounter similar conditions in places with similar geography.

As Portofino describes deep V hulls with sharp progressive entry at the bow seem to me to give the smoothest ride and take away the jarring and banging almost regardless of sea state as the hull first cuts the waves rather than just climbing and falling. I don't think the propulsion system makes much difference to ride quality either.
Wind against tide is always hard work what ever you are in. Wind with tide is good as long as you are going with the tide etc. Some boats really don't like waves coming beam on, others are great when you approach the waves at an angle - just watch if waves are coming up behind you and overtaking you - some boats will want to broach in properly big waves (swing the stern around rapidly - can be quiet alarming)

So which boat to pick? I can only describe some examples I have owned. Also to maintain some stability on a motorboat you need to be going at least 10Kns and preferably planing.
As a good all rounder I found a sealine F43 pretty good in most sea states that most people would be out in. It was OK in short chop and didn't jar or bang.
I had a fairline Targa 43 that was very good in most sea states. It would occasionally shudder in small close waves approaching at an angle but never jarred or banged. Long narrower hull, sharp bow.
I had a sealine T50 that was very good in big long waves, and fast, however in short choppy waves it was annoyingly harsh, especially on the fly bridge. Every time it hit a wave you rock forwards in your seat - gets wearing after a while. Almost like riding a horse. That had a flattish bottom and bluntish bow similar to a lot of new boat designs. If I left a half full can of pop on a flat surface it would always fall over and the binoculars/hand held VHF etc would all have to be put somewhere they couldn't move.
Current boat is Rodman 38 which is a bit of an odd ball planing design. Very sharp bow entry and deep V until 2/3 of the way back with a keel. Its almost a semi displacement hull. Its quite wide for its length so a bit of a fat lass, however the ride is remarkably smooth in anything. Friends who have been out on the previous T50 remark upon it as it is very quiet and smooth. The penalty for the ride is it is relatively thirsty compared to an equivalent 38 - 40' boat. Now though I can leave a half full can of pop on a flat surface and up to a good F4 it won't move. The binoculars just stay on the seat next to me.

Smoothest riding boat I have ever been on was a proper semi displacement boat - like driving through cream, but they get very thirsty at speed.

 

[IDAMAY]

very difficult to give a definitive answer as everyone regardless of their level of experience will have a different view of ride quality when the wind picks up. No boat is perfect they are all some sort of compromise and I think the newer boats are worse rather than better as they manufacturers strive for 30kn+ and lower fuel consumption. The often used solution is a flatter bottom and blunter entry at the bow. There is nothing especially different about the solent - it's tidal and the wind speed/direction changes. You can encounter similar conditions in places with similar geography.

As Portofino describes deep V hulls with sharp progressive entry at the bow seem to me to give the smoothest ride and take away the jarring and banging almost regardless of sea state as the hull first cuts the waves rather than just climbing and falling. I don't think the propulsion system makes much difference to ride quality either.
Wind against tide is always hard work what ever you are in. Wind with tide is good as long as you are going with the tide etc. Some boats really don't like waves coming beam on, others are great when you approach the waves at an angle - just watch if waves are coming up behind you and overtaking you - some boats will want to broach in properly big waves (swing the stern around rapidly - can be quiet alarming)

So which boat to pick? I can only describe some examples I have owned. Also to maintain some stability on a motorboat you need to be going at least 10Kns and preferably planing.
As a good all rounder I found a sealine F43 pretty good in most sea states that most people would be out in. It was OK in short chop and didn't jar or bang.
I had a fairline Targa 43 that was very good in most sea states. It would occasionally shudder in small close waves approaching at an angle but never jarred or banged. Long narrower hull, sharp bow.
I had a sealine T50 that was very good in big long waves, and fast, however in short choppy waves it was annoyingly harsh, especially on the fly bridge. Every time it hit a wave you rock forwards in your seat - gets wearing after a while. Almost like riding a horse. That had a flattish bottom and bluntish bow similar to a lot of new boat designs. If I left a half full can of pop on a flat surface it would always fall over and the binoculars/hand held VHF etc would all have to be put somewhere they couldn't move.
Current boat is Rodman 38 which is a bit of an odd ball planing design. Very sharp bow entry and deep V until 2/3 of the way back with a keel. Its almost a semi displacement hull. Its quite wide for its length so a bit of a fat lass, however the ride is remarkably smooth in anything. Friends who have been out on the previous T50 remark upon it as it is very quiet and smooth. The penalty for the ride is it is relatively thirsty compared to an equivalent 38 - 40' boat. Now though I can leave a half full can of pop on a flat surface and up to a good F4 it won't move. The binoculars just stay on the seat next to me.

Smoothest riding boat I have ever been on was a proper semi displacement boat - like driving through cream, but they get very thirsty at speed.

That is all true but as I posted last year, it can be overcome with a good stabilization system. Although the boat is perfectly capable, we wouldn't plan to cruise in a F6, especially in wind over tide conditions but we will take on a F5 and don't hesitate when its just a F4. The stabilsers mean we rarely need to use power to get over the hump and can keep fuel consumption at tolerable levels. I may be tempting fate but in 4555 Nm cruising since 2015, including twice all the way round the Bay of Biscay, we haven't yet spilt a drop of coke or other more medicinal liquid.

 

[Nigelpickin]

That is all true but as I posted last year, it can be overcome with a good stabilization system. Although the boat is perfectly capable, we wouldn't plan to cruise in a F6, especially in wind over tide conditions but we will take on a F5 and don't hesitate when its just a F4. The stabilsers mean we rarely need to use power to get over the hump and can keep fuel consumption at tolerable levels. I may be tempting fate but in 4555 Nm cruising since 2015, including twice all the way round the Bay of Biscay, we haven't yet spilt a drop of coke or other more medicinal liquid.

I remember leaving Bayonne with you and heading towards Zumaia, Breaking Bad was heeling like a pig, we looked back at Ocean Spirit and you were steady as a rock with the huge swells on your beam - we sped off in the wrong direction with Ann asking me why I hadn’t bought a boat with stabilizers

 

[[2068]]

Appreciate that views will differ, but I'd like to understand a bit more about how the weather, wind-over-tide, short choppy seas etc, curtail your cruising? How well does your own boat cope?

Our Sealine SC35 ploughs through most things reasonably well.
Had to slow down a few times for 2m waves off Selsey Bill on the way to Brighton, and I will back off to a minimum planing speed if things start to get uncomfortable, but most of the time it just chugs along at 19-22kts.
My personal limit is an F5, anything more than that is hard work, especially docking, and it is supposed to be a leisure activity.
Surfing down the waves into Chichester Harbour wind-over-tide is fun if you know what you are doing
Trying to go the other way in the same conditions, probably not such a good idea.

SC35 hull has a really quite deep forefoot, and carries that V quite a way back, despite being wide.
So it's good for its size at squashing waves.
But it's not so good with regards to top speed / fuel consumption.
A Targa 40 would be a lot faster.
Swings and Roundabouts ...

.

 

[Sticky Fingers]

Thank you folks for your replies, that's very helpful.

Pretty much all D and SD boats will roll in beam seas unless fitted with stabilisers. Very few, if any, boats around the 40 foot mark will have stabilisers as OE and retrofit is likely to break your budget pretty quickly. We part solved the problem with the Trader 42 by upping the speed in beam conditions. This gave extra dynamic stability at the cost of greatly increased fuel consumption. Anywhere near max speed the fuel consumption instrumentation got quite frightening!

We finally solved the problem by changing to the Trader 54 you see in the avatar. She is fitted with ABT Trac stabilisers and they are amazingly effective and mean we cruise around 8 kts almost all the time at reasonable fuel consumption levels and with no heel and almost never roll.

IDAMAY has a stabilised boat - Appreciate the cost looks pretty horrendous but has anyone retrofitted a 42-45' sportscruiser with a Seakeeper?

 

[Portofino]

Thank you folks for your replies, that's very helpful.



IDAMAY has a stabilised boat - Appreciate the cost looks pretty horrendous but has anyone retrofitted a 42-45' sportscruiser with a Seakeeper?

What’s the main problem you are trying to solve ?

If the weight distributions is adverse ( not wrong ) sub optimal like a sterndrive , Or theres dead rise insufficiency because there’s no enough HP to go fast enough from a lift POV so they deliberately flatten it off , and the forefoot is not sharp then it will slam earlier and force the driver to back off .
Once at semi planing - keeps getting knocked back as it’s now running up and over ,sort of roller coasting up and down 2-3 M waves as opposed to slicing through then that’s gonna put her off ?

Your seakeeper in a 42/40 odd ftr will add weight , but where ? Could knacker an already duff balanced boat ?
AND it may help with D speed roll but won’t help enormously with wave pitch , if you end up running on them as opposed to slicing through .

Obviously ours is at the cutting edge ( scuse the pun ) of hull comfort in planning boats and I was in exactly the same position as you regarding wife compatibility with the “ hobby “ .

That’s all a distant memory now with my 23 degree dead rise mid engined , zero superstructure heavy (17770 kg ) Itama .
Ok the massive MAN 13 L engines gobble more fuel than a longer , bigger but lighter Targa 47 with D9 ,s but we keep going smoothly planing at 26/28 Knots that a T47 back off in .From personal experience btw .

A compromise worth accepting .

Went cruising on Co with a mate running a Portofino 47 IPS 600 , he repeatedly kept coming over on the VHF “ drop the rpm “ as 26/28 ( end of season ) was too fast and uncomfortable for him but nought / normal / dead smooth for us .
Dropping down to 20/22 his comfort zone was actually worse for us on two counts ,

1- our engine rpm at or just below turbo spool so they are hunting .

2- we loose dynamic anti roll stability from the hard chimes .

2 ^^^ is the point re seakeeper.
If your hull shape and weight distribution is right in the first place the faster you go the more stable she becomes in ROLL as well .

You sort of speed your way into a better comfort zone - yup push the throttles fwd not back down .

Aside from the dynamics fitting a sea keeper to a small boat it’s needs powering as well - geny running or a crazy inverter = added layer of hassle imho .

Maybe as a last chance saloon take her to the SoF ( holiday ) or Naples and get a ride out on an Itama tripper boat .

 

[Portofino]

Let’s go back to 1966 .
E type Jag V12 , 150 mph in a straight line ———— owners whinge about handling, narrow wheel base , narrow track , poor steering ratios , or is it the narrow tyres ?

Nope it’s staring the drivers of E types literally in the face —— the ( insert your own expletive ) ... ing engines in the wrong place -
https://m.youtube.com/watch?v=Zly8XKIsDJk


So look at your hull form carefully for best ride .

 

[IDAMAY]

Thank you folks for your replies, that's very helpful.



IDAMAY has a stabilised boat - Appreciate the cost looks pretty horrendous but has anyone retrofitted a 42-45' sportscruiser with a Seakeeper?

A friend of mine has fitted Seakeeper to a Broom 450. I think it was the first such. He got a very good deal because of that. He claims the Seakeeper is not as good as fins would have been but much better than none, especially at displacement speeds. Fins would, in any case, have been very difficult if not impossible to fit in the Broom.

 

[Sticky Fingers]

Hi Portofino, thank you.

The main problem I want to solve is about comfort and perceived stability in moderate conditions, by which I think I mean F4 / choppy / beam seas. F6 we'd never choose to go out. F0-2, no problem in any boat. So it's the ability of the hull form to provide a stable platform at an acceptable compromise of speed and fuel burn, in these conditions. I understand the theory, and the effect of the hull form and weight /CoG / CoB distribution on ride and fuel burn reasonably well (I did Naval Architecture at Uni) but it's about how things play out in the real world. No experience of power of that size.

The trigger is that she doesn't like sailing, so the proposal is to sell the nearly-new saily boat and buy an older mobo, but there are compromises that she and I both have to make. We want something that approaches our 42' yacht in terms of accommodation, but she won't consider a flybridge or a "traditionally styled" boat eg Hardy or Aquastar (that said, she liked the Elling) and wants to get places reasonably quickly, so full D eg Linssen or Van de Valk is out. We use the boat as a weekend apartment in the winter so the accommodation is important. Summer use is sociable / outdoor focussed so we want a sizeable, well equipped and comfortable cockpit space. Something over 50' in the UK compromises marina availability (and cost) quite a bit, so we've pretty much ended up with a sportscruiser about 44' as the likely choice.

I know from your posts that you love your Itama and similar Italian boats, in the Med I get it, but for us the UK I think in addition to the accommodation factor we also need to think about resale, so it's very likely to be something from the usual suspects ie Princess V class, Sunseeker Camargue or Portofino, Fairline Targa, Sealine.

Was looking at a 2002 Camargue last night (online) just sold with Sunseeker brokerage. That kind of thing.
https://www.yachtworld.co.uk/boats/2002/sunseeker-camargue-44-3488845/

 

[MapisM]

The main problem I want to solve is about comfort and perceived stability in moderate conditions, by which I think I mean F4 / choppy / beam seas
...
wants to get places reasonably quickly, so full D eg Linssen or Van de Valk is out.

Ok then, bad news/good news time.

The bad news is that if you want proper comfort at 30 kts in rough sea with a sub 50 footer (and also larger mobos, for that matter), you will never get it.
Don't buy the idea that some boats can offer that, because it's impossible.
Magnums, Otams, Itamas and the likes are certainly able to keep going fast in rough conditions better than other more sedate boats.
But with none of them you will cruise REALLY comfortably at 30+ kts in an F4 beam sea (remember, F4 means up to 8 feet waves), period.
They CAN keep going without falling apart, which is great, but having a pleasant ride is something different, in my books.
On boats even more specialized than those for high (also much higher!) speed in rough conditions, they don't fit suspension mounted bolster seats with 4 points safety belts for nothing...
So, if you want to cruise an F4 beam sea and boil pasta, have a shower, use the toilet normally rather than to puke into it, either you go up in size enough to call the vessel ship rather than boat, or you go for D/SD stabilized boats, and accept one digit speed.
There's no magic wand that can bypass physics.

Otoh, I understand and accept your wish to not be restricted by a full D hull speed, and also the fact that if you think to go fast(ish) most of the time, a P hull is better and more efficient than SD.
So, here's the good news: most half decent P boats can withstand cruising in F4 conditions at their "normal" speed, say low 20s.
And this means that you can essentially pick whatever you are more pleased with, without bothering too much about the hull seaworthiness, which in pleasure boats is way overrated, if you consider dock (and forum!) talks.

We had this discussion with Portofino in the past, because he tried and ruled out other boats that he found not as good as his Itama at wavecutting. Which is hardly surprising, but my point is that P hulls cutting through waves are just a theoretical oxymoron, and the fact that some are better than others doesn't change the fact that you need the size of a cruise ship to cut through the water at anything above 20kts.
For smooth riding in a pleasure boat, for any given size, if a full D hull at 8 kts scores 10 on a 0-10 scale, an Itama at 30 kts can maybe score 3, if that.
Now, I'm the first to recognize that other P boats score less - say 2. And 3 is 50% more than 2, which is perceivable.
But we are still talking of 2 or 3 vs. 10, if you see what I mean...

 

[Portofino]

Thx Scala ,talk about deja view .I was in exactly your place .
As you say being Med based fortunately opened up a few more options .
As you say no one intentionally goes out in a rough sea for boat there size .
Your rationale for forty something makes perfect sense through my eyes btw .
How ever you do get caught out sometimes more often than not and with a delicate crew it ruins the experience to point of contemplating packing up .
@ Mapish where did cruise at 30 knots enter in to the equation and silly suspension seats ?

What you don’t want to end up doing getting a boat is being the first to have to back off from say a respectable mid twenty knot say 25/27 range , drop it down to low twenties say 20/22 because of slamming / harshness / fear of interior self rearranging the cupboards etc , then getting into excessive roll or pitching because the waves ( if up wind or on 1/4 ) start to tip it .
Of course drop right down below planing ( for me 18/20 knots ) but most others 16/18 to D and end up wallowing about , pitching about etc etc because basically the hull can’t cope with what’s presented in comfort .

It’s the sum of all the parts , every detail not missing anything staying focused on seakeeping in the design all the way that’s the key .

Our previous boat a Porto 35 was ok ish but not brilliant we often had to back off - wrong weight distribution ( sterndrive s ) and although a fine entry a flat stern sections that were easily slammed .

So how did I drop into all this malarkey?
Watched
Saw others make remarkable smooth headway as they slid past us and many others in a chop/ big sea / rough weather - comparable size MapisM.
In fact on day in a pique of fit after a particularly rough few days out ( wife getting to end of tether ) a Rivarama 44 just slid past us looking dead flat parting waves ( white horses - ladies sunbathing on the bow etc totally relaxed ) .We could not plane , getting wet from spray etc taking ages to travel across the 5/6 waves that had blown up in the bay .When we arrived in port we jumped in the car and shot straight off to Monaco, to visit Monaco marine .They had one on the hard .
Got chatting to the guys , bared our souls and the guys walked us across the road to the one on the hard and went through the whole dead rise naval architecture thingy with wife and myself .
They were asking just a bit more than we were prepared to pay and aside it was a large single cabin in a day boat kinda way .So the guys said “ take a look @ Itama “
Next day we were in a hanger near Cogalin , in there was 3 Itama , 2 Pershings , many other brands like Priny V something s 2 helicopters, 5 Harley’s + many more boys toys .
Armed with only 24 hrs of knowledge from Monaco marine looking at the Itama hulls , much more aggressive than anything else in the hanger .
That salesman ( has in fact two independent just used the same hanger ) said the same thing .
So I was getting consistent information re seakeeping and soft ride .

There’s a formula re vertical acceleration and seakeeping I can’t remember off hand but iirc for every degree of deadrise the Vertical A is reduced by a factor of - either squared or better to the power of 3 ? or even cubed I can’t remember sorry .
So say a 45 ftr with a 19 deadrise will ride a lot worse than a 22 or 23 degree .Most other stuff being equal .
Other stuff is proportional like and extra ft longer or 6 inches narrower etc .
A small increase in deadrise has a disproportionate positive effect on the ride .

I out ran a Princess 20 M once .He dropped off the plane and started to ride the roller coaster he created .We speeded up and it got smoother for us .
Once retiring from the Monaco GP the the Sunseeker guys ( hospitality) in a Hat 60 in a big sea on the nose followed me back in our wake .Ok we dropped a bit to 24 /26 .He even came fairly close up my arse .
Every few mins “ guests “ leant over the side and puked .
When we got back he came round and apologised for tailing me so close - guest puke issues .

We were totally relaxed cool a cucumbers enjoying the rough .

So be careful just chucking money at it and going larger .
I have watched that NOT work MapisM.

You guys can run around in the E type I,ll take the Muira thank you

 

[vas]

You guys can run around in the E type I,ll take the Muira thank you

I'll have an orange one please, ta!

V.

 

[MapisM]

Porto, I'm well aware that you have the strength to argue about this point till the hell freezes over, and I really don't want to.
But just to make my point even clearer, this is where we have a completely opposite view...

staying focused on seakeeping in the design all the way that’s the key

...because imho, seakeeping in a pleasure boat does NOT really matter.
And I'm saying that after 17 years spent boating with a tub that would keep going steadily in conditions where any Itama should run for cover.

Let's forget the dock/forum talks - as I previously said, seakeeping for some reason is a subject which attracts more endless debates among sunday boaters like most if not all of us, than among folks who are out there 24/7.
Just consider the reality, and look at some forum P boats off the top of my mind - with apologies to all others which I am forgetting:
Sq 58+65+78
Prin 57+67
Fer 46+53+630
AZ 39+55
Several FL Targas
Sskr MY70+80
Canados 70
Prestige 680
DP56

Now, if having an Itama-like ride would be crucial for pleasure boating, all the above folks (bar none, and myself included!) would have made a wrong choice.
If this is what you are saying, fine, I have absolutely no problems to live with that. And I'm pretty sure that the same goes for all the above forumites.
But you'd better come to terms with the fact that this is just your opinion, not gospel truth...

 

[MapisM]

I'll have an orange one please, ta!

Me 2, but just to put it in the garage as an investment, and listen to the engine sound now and then.
I always thought that back in those days, when Gandini sketched the Miura, he must have been either on LSD or inspired by God (or, more likely, both).
But if there's something the Miura is notorious for, is its terrible handling, and there are people killed to prove it.

Don't tell PF that I said this, though.
I'm not sure to have the strength for a debate also on this topic... :sleeping:

 

[Portofino]

Porto, I'm well aware that you have the strength to argue about this point till the hell freezes over, and I really don't want to.
But just to make my point even clearer, this is where we have a completely opposite view...

...because imho, seakeeping in a pleasure boat does NOT really matter.
And I'm saying that after 17 years spent boating with a tub that would keep going steadily in conditions where any Itama should run for cover.

Let's forget the dock/forum talks - as I previously said, seakeeping for some reason is a subject which attracts more endless debates among sunday boaters like most if not all of us, than among folks who are out there 24/7.
Just consider the reality, and look at some forum P boats off the top of my mind - with apologies to all others which I am forgetting:
Sq 58+65+78
Prin 57+67
Fer 46+53+630
AZ 39+55
Several FL Targas
Sskr MY70+80
Canados 70
Prestige 680
DP56

Now, if having an Itama-like ride would be crucial for pleasure boating, all the above folks (bar none, and myself included!) would have made a wrong choice.
If this is what you are saying, fine, I have absolutely no problems to live with that. And I'm pretty sure that the same goes for all the above forumites.
But you'd better come to terms with the fact that this is just your opinion, not gospel truth...

Feels like you have misread the title and don’t understand the “raison d etre “ of why and what is Scala is enquiring about ?

Mrs Scala has tried AN OTHER boat and it did not go well .
Where I differ from you is there are not minor difference to the point of pretty insignificant in hull design so it does not really matter choose any , if I understand your line of thrust ?

I know there are huge significant differences in hulls performance at all size bands relative to each other in seakeeping.
I have seen it , I have experienced it and it’s not exactly rocket science it’s not random pot luck .Its a science .

You can’t NOT consider hull form in Scalas predicament. I know I have been through it with Mrs PF :encouragement:
Three and actually another making 4 boat professionals got us where we are now .

Ok are you saying if you walk down to nearest used car lot and say “ I want one to complete in the Paris Dakar “
They are gonna say “ any of theses will do sir “ “ in fact this ones got a sun roof , a cup holder in the back too “

Then gaze at the cars passing in the street and say “ look they bought cars from me , what’s wrong with them “

There’s nothing critical of those “ normal “ car owners if I walk away and seek specialists advice .

Fit for purpose springs to mind not criticism of others cars and topically boat choices. surley .

 

[MapisM]

Feels like you have misread the title and don’t understand the “raison d etre “ of why and what is Scala is enquiring about ?

Mrs Scala has tried AN OTHER boat and it did not go well.

Can you please point me to where in this thread the OP said that they tried another boat, exactly?
Aside from the sailboat of course, which in the "which mobo" context is totally irrelevant.
The fact that I don't think Itamas are the be-all and end-all mobos doesn't imply that I misread and/or misunderstood anything, you know.

And I'm still waiting to hear if you think that all the the P boats in my previous list are not fit for purpose, considering that most of them are typically used precisely for the same purpose as yours - i.e. going to the Lérins Islands (or whatever) in glorious weather and enjoy the day at anchor.

 

[Portofino]

And I'm still waiting to hear if you think that all the the P boats in my previous list are not fit for purpose, considering that most of them are typically used precisely for the same purpose as yours - i.e. going to the Lérins Islands (or whatever) in glorious weather and enjoy the day at anchor.

Last two lines of the preceding post above #56 was the answer to that .

If the OP can join the greater than 20 degrees dead rise club in his chosen size range then I think his wife’s protestations in stuff over” F2 dead calm “ will evaporate. That was our experience and I no reason not to share that nugget .

I gave that list in my first post here and realise due to location ( N EU ) and possible re saleability and weather protection his choice is limited.

Having said that Dustywings on bear ran a Riva Bravo 38 around the solent iirc .So it’s not unheard of importing a “ open “ for U.K. weather .

 

[Portofino]

MapisM Scala reports previous training in navel architecture ..
So I feel justified posting this
http://oa.upm.es/14340/2/Documentacion/3_Formas/Savitskyreport_conSemidesplazamiento.pdf

Go to page 19
See the dead rise comments and further the running angle trim comments .
See the graph no 11 . Not the vertical acceleration reductions .

I have not brought trim into this because it seems to me folks like you just ridicule the science .
The best seakeepers run at less than 4 degrees.Mine needs zero flap to plane or run at all .It just runs flat .Well under 4 degrees .So now we are drifting into Cog , Mid engines away from rear engines etc .
As I said It’s the sum of ALL the parts added up .Drop bits and you start loose it from a sea keeping POV .

Many of the boats we slide effortlessly past in a big sea are FB and appear to be attempting some sort of moon shot , the bows that high - totally $hit trim and they wonder why they have to back off .

And ps google is your friend and I use it and quote it ( sometimes) because it save me explaining stuff .

Amarti was not alone , Ray Hunt , Theodoli ( sorry Sp the Magmum designer ) your Buzzi pal and a few more .Unfortunately I can’t write although I wish I could ....... “ a lot more “

 

[Sticky Fingers]

I get all of that and the NA is correct. I don't think anyone is disrupting that a 25deg deadrise boat optimised for planing will be more comfortable and ride more smoothly and probably use a lot less fuel, than a similar size/mass 12deg boat optimised for space (or whatever).

My point was more about what others' real world experience of their own particular boats in those kind of conditions might tell me...