Midnight Lace

I've always been a bit of a Tom Fexas fan. I particularly like the results of his earlier collaboration with Cheoy Lee, designing their range sportsfishermen, fast motoryachts and of course the Midnight Lace series.
In conjunction with Rex Yacht's, Fexas is reincarnating the Lace range with new 42 and 52 footers. But a few minutes of browsing over the web site ( http://www.rexyachts.com/midnight/ ) leaves me wondering whether this isn't simply an attempt to ride the current wave of popularity for all things retro, with little regard to the fundamental principles that made the originals so successful, or whether design has moved on to the point where 'long, lean and light' are no longer the necessary attributes for producing an efficient and fast motoryacht.

Some figures:

The original 44 weighed in at 17500#, had a beam of 11', giving a length/beam ratio of exactly 4. With a pair of 220hp diesels the 44 managed a top of 27 knots and cruised at 20, using a total of 220hp and 10.5pgh. It was very efficient throughout its speed range.
Yet the new boat at 42' LOA has a beam of 14ft, blowing the length/beam ratio out to 3. It is also heavier at 25000#. Yet with only marginally more power (a pair of 250hp yanmars) the boat is still expected to have a top speed of around 25 knots. I couldn't find any other performance estimates, like those given for the original boat.

So, have we moved on to the point where fat and heavy (well, heavier) can still be economical and efficient, or am I right to be somewhat sceptical of the new Midnight Laces credentials?.......

 

Will,

Once a boat is well up on plane, the length is not a big factor in determining speed potential. The new boat appears to have a bottom loading (when planing) only about 11% over the older one so the extra power should be enough to make similar speed. It may have a higher initial planing speed.

Like you, other things being equal, I'd prefer the longer one for greater comfort and probably lower operating costs.

 

One of the things Fexas points out in articles written at the time of the original Lace's release is that the boat by his definition never actually gets on the plane - he termed the hull as a penetrating hullform. Hence he incorporated features such as round chines to help the 'slip' through the water.
Take a look at one of those articles http://www.rexyachts.com/midnight/acase.html
Now the new boat is no faster, yet incorporates hard chines etc. Perhaps the new boat is designed to plane at lower speeds?
But then one of the greatest attributes of the original was its ability to travel at almost any speed without efficiency penalties. Indeed he points out that a pair of 130hp engines would give the boat a cruise of 18knots. I wonder if the same could be said of the new boats?.......

 

Will,

It's useless to get into an argument about what constitutes planing but at a speed of over four times the sq root of waterline, it's clear that much of the weight is being supported by dynamic forces. The 44 is in no way long enough or narrow enough to escape the need to plane to make this much speed.

I too doubt that the new one has the broad speed range of the old, but that is the way things have been going in power boats for some time. The new boat is actually bigger than the old and costs less to berth in a slip.

 

All too true Tom - but (with me there's always a but ) with a waterline length of 40ft, 4x its square root is actually 25 knots - exactly the point Fexas makes in that article I posted a link to in my last post, so by that definition the hull is still not truly planing at 20 knots (the designed cruise speed of the 44).

I have no doubt that you and I are of exactly the same opinion when it comes to how the new boat will perform in relation to the old - I'm just waiting for someone to tell me I'm wrong. You only have to take a look at "Liz" to see that a boat can be designed to be truly on the plane at speeds well below the theoretical minimum, but given the weight of the new Lace, I'd be surprised if this boat could manage the same sort of efficiencies.

And it's not that I doubt Fexas's ability to create an efficient up-to-date hullform - as I said at the outset, I'm somewhat of a fan. It's just that the new boat seems to have completely abandoned the principals of the old. If I'm correct, then the new boat becomes simply a marketing exercise - trading on the success of the original design, yet incorporating none of the elements that earned it that succcess.

 

As Cool Hand Luke's chain gang guard would say "What we have here is a failure to communicate".

I did not mean to give any limits to what is and what is not planing, just that at 25 or even 20kts, the boat is running at many times the square root of its waterline length and must be getting a fair amount on dynamic support. This is true for all boats other than those having very high length/beam ratios which can run at pretty high speed in displacement mode. Neither of the Fexas boats have ratios high enough (generally considered to be 10:1 or more) to fit this profile.

So it is my guess that Fexas was using a customer bias against rough riding planing boats to market the original by claiming that his 44 footer was not a "plaining hull".

 

Quite possible Tom. It must be said though that the original boat was way more efficient than most boats produced both then and today. And the thing I like most is that it remained efficient regardless of speed. I guess this is a result of light weight, narrow beam and hullform......