As we work on a new design we frequently refer to past projects. We used to overlay paper plots of lines drawings and compare how volume was handled above and below the waterline. There are the numeric values to review of course, but in the end, when you are talking about how a given shape is going to work at sea the designer has to visualize the hull in various combinations of waves. To aid in this process we would often scale the drawings so they were the same size to make comparisons easier.
These days we do this on the computer screen, importing various historic hull shapes into the new design and doing an electronic overlay. These are sized for comparison so the effects of scale are lost.
Occasionally we’ll look at unscaled hulls, so the difference in size is apparent. That is the FPB 112with the FPB 64 and 83 inside (above) and alongside (below).
When you work on a project like this sometimes the sense of size is lost as one becomes intimate with the details. Size comps bring reality into the thought process. When you look at the FPB 64 almost lost in the 112 hull, and then ponder docking in a small harbor with a gale blowing, you are apt to make better decisions. Six Lewmar 55 powered deck winches, which originally sounded like overkill for handling dock lines, all of sudden feel just right.
We thought we had the preliminary design wrapped, and then a friend perusing the the drawings did some prodding. Stay tuned.
Posted by Steve Dashew (March 16, 2011)
March 16th, 2011 at 1:49 am
Unlike Goldilocks and the Three Bears, the one in the middle (the FPB 83) is the one that looks “just right” to me. I’m sure the 112 will look good in real life, but I think the humans on board will be starting to look like minitures.
March 16th, 2011 at 9:21 am
Howdy Ward:
I can tell you from personal experience that size large is something that is easy to get used to. When we first looked at Intermezzo, a diminutive 50 feet, she seemed huge. It took one sail to Catalina to adjust. The FPB 112 is a big yacht, and when she is under construction will inspire a degree of awe. But within a week of launching she will become the new norm. The real key is not the size per se, but how easily handled she is in tight quarters. Our goal is for experienced owners to operate her as a couple, if desired. We think we are on the right track with maneuverability and winches. Time will tell.
March 16th, 2011 at 6:34 am
Very interesting. Does the FPB 83 draw more water than the 112 or am misreading that bottom view overlay? If so, fascinating, though I do note the overlays don’t include keels or skegs which almost certainly will impact draft. Thanks for sharing.
Best,
Robert
March 16th, 2011 at 9:24 am
Hi Robert:
The FPB 112 actually will draw a touch less than the 83, just under five feet/1.5m. The 112, like the 64, is able to sit on its bottom for maintenance or fun, and does not have a keel (like the 64).
March 16th, 2011 at 8:07 am
Steve,
I can’t help but notice the raised forefoot on the 112, an interesting departure from what you’ve done on the previous boats. The new forefoot looks suspiciously like that of the big Canadian and Russian polar icebreakers; are you planning some degree of ice breaking capability for the 112?
March 16th, 2011 at 9:30 am
Hello Matt:
Ice breaking… We would never call the FPB 112 an ice breaker. But, she will have the ability to deal with moderate amounts of ice, as do Wind Horse and the 64s. The bow shape will allow her to ride over ice if required. But if you were planning long term operation in ice, say the NW Passage, consideration should be given to removing the stabilizer foils and replacing the props with those designed for impact.
March 16th, 2011 at 8:11 am
Steve, at what point does something like an azipod drive become practical?
March 16th, 2011 at 9:34 am
We have not recently looked at azimuth drives. If you are referring to something like the Volvo pods, these are designed for high speed applications. Also, they are more vulnerable to debris and grounding than what we are doing.
March 16th, 2011 at 3:57 pm
Hi Steve, this is Pedro from Barcelona, I think Rick is refering to electric azipods like the ABB’s that almost cruissers (Queen Elizabeth and so)use but on a much smaller scale. I’m also thinking about diesel electric from very long ago. But after reading all you write I guess you will consider it unnecesarily complicate. The system is extremely good from manouver point of view, and at least on big ships very efficient. I see azipods keel protected and with counter rotating props.
March 16th, 2011 at 4:42 pm
Steve,
Interesting tool! Thus, the 83 has a fuller bottom (bilge?) than the 64…i.e. the 64 is flatter amidships on the bottom? Are there thoughts of a transom extension as well? The transom extension could have Dingy bow “dock” for the entry and exit of passengers or is this a relative non-issue when anchored?
As always, thanks for allowing us to tag along!
March 17th, 2011 at 12:38 am
Howdy Michael:
I guess the comparisons are decieving. The 83 is flatter than the 64 or 112. The transom extension is built into the length of the 112.
March 16th, 2011 at 6:19 pm
Hi Steve
Will you be back from New Zealand early in April ? I will be in Fort Lauderdale April 6 to 9 as I mentioned in January.
With a bit of luck might have a chance to say hello .
Very best regards
George Ponte
March 17th, 2011 at 12:36 am
Hi George:
We have not firmed up dates yet for our return to the boat, but around t he 5th/8th of April looks about right.
March 16th, 2011 at 6:22 pm
Hi Steve,
Now I’m convinced that the waterline beam of all three boats is identical.
March 17th, 2011 at 12:35 am
No Max, the waterline beams are considerably different.
March 17th, 2011 at 12:26 pm
Steve,
So interesting watching the design process from the outside. Looking forward to seeing what “prodding” turns up.
Hanging on faithfully with bated breath.
March 25th, 2011 at 11:40 pm
Speaking of scale, how far down scale will these designs work?
30 to 40 ft picnic boat?
March 26th, 2011 at 11:57 pm
Hi John:
The FPB scales both ways, but we have not looked at anything under 65 feet/20 meters.
March 31st, 2011 at 6:19 pm
Hi Steve,
In another post you mentioned working on reducing the skeg draft on the 64 as it is the low point. Will this happen in the series 2?
April 1st, 2011 at 1:14 am
Howdy Steve:
The FPB 64 draft is under five feet/1.5m at full load with full prop protection. I don’t think we’ll get it much shallower.
May 12th, 2011 at 5:40 am
Hi Steve,
do you think about azimuth drives? The last weeks I have seen a lot about Voith-Schneider drives (http://www.voithturbo.de/vt_en_pua_marine_vspropeller.htm). You can drop the stabilizers (remove with twin keels for drying out), could drop the rudder ….
No more problems with tight harbors!
Hope to read more about the 112.
Greetings to Linda, i remember the nice afternoon in Puerto Calero.
May 12th, 2011 at 2:46 pm
Hello Gerhard:
Azimuth drives are great for low speed high torque operation, but not as good f or an easily driven hull as we have. The 112 is designed to dry out now, the same as t he FPB 64.