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Author Topic:   Newer Boston Whaler Hull Designs
jimh posted 03-14-2004 11:18 AM ET (US)   Profile for jimh   Send Email to jimh  
At the 2004 Miami International Boat Show, I had a chance to meet and talk with several of the people from Boston Whaler who design, build, and market the new boats. I learned quite a bit. I'll have to paraphrase the answers and questions, as I didn't have a recorder along, nor did I take copious notes. So this is a loose reconstruction of those conversations:

Q:How many boats in the current line share the same hull?

A:They are just about all different. The only boats that share the same hull mold at the moment..(thinking)..are the 21-foot Ventura and Outrage. All the others have their own hull mold.

Q:You must have a lot of molds!

A:Yes, (laughs) we do! But this allows us to make adjustments to the hull form as we need to. For example, on a boat like the Conquest we have to put more buoyancy into the hull in the bow because of the weight of the cabin structure. On an Outrage of similar size, we don't need that buoyancy in the hull.

Q:That is interesting, because in the old days one hull form was adapted to several different boats, like a Revenge, an Outrage Cuddy, and an Outrage, right?

A:Yes. Now we can tweak the hull to match the application.

Q:Are you constrained by SeaRay or Brunswick into making just certain boats? Are you told your boats have to fit into a niche in the overall product line?

A:No, not at all. We can make the boats we want. We do make use of the resources we get from SeaRay, like their CAD tooling facilities. But we are free to do what we want with the boats. A lot of time we develop some new details or methods, and they are picked up by others in the group, or we might get something from them. Being part of the Brunswick/SeaRay Boat Group has been great.

Q:Is everything designed on a computer and a CAD system?

A:No. Things like consoles are built up in full size so we can see how they feel and look. A craftsman will make up a model from wood and other materials--even plaster--and then we see how it works. When we get the design just right, then we can make a mold for it for production.

Q:Do you do structural analysis?

A:Yes. Like here (pointing to curved section on deck molding). If this curve is too sharp you will get a lot of stress cracking here. We can control this and make it just right--no stress cracks.


I got the distinct impression that the people at Boston Whaler are very involved people. They are quite intense about the boats they make and proud of them.

Come down to the factory-sponsored Boston Whaler Owners Event and Fishing Tournament at Stuart, Florida on April 16-18. Many of these same find folks from the factory will be on hand. You can ask them your own questions and get the low-down on current Boston Whaler boats!

BEACHPANDA posted 03-14-2004 01:21 PM ET (US)     Profile for BEACHPANDA  Send Email to BEACHPANDA     
Please forgive my neophite naivate, but I was under the impression that BW hulls are foam filled, and the hull pieces are clamped together to create a unibond structure. Am I right?

If that's so, then the comment about putting more foam into the bow of a Cuddy version of a BW hull seems amiss. Either the full hull is filled with foam, or only the Cuddy versions of the hulls are.

If only the Cuddy versions are fully filled with foam, creating the full unibody construction strength, then does that mean that the Outrage, Sports, and other BW vessels have a weekness in the bow strength and floatation?


jimh posted 03-14-2004 01:23 PM ET (US)     Profile for jimh  Send Email to jimh     
Hull form buoyancy has nothing to do with foam fillings.
BEACHPANDA posted 03-14-2004 01:27 PM ET (US)     Profile for BEACHPANDA  Send Email to BEACHPANDA     
What about strength?

Does that mean that the entire hull is no longer foam filled, in certain models?

The structual analysis that BW does may have satisfactory results, but I'm surprised.... again if I understand correctly... that BW is cutting corners by not fully foam filling ALL of their hulls.


Richard Quinlivan posted 03-14-2004 01:40 PM ET (US)     Profile for Richard Quinlivan  Send Email to Richard Quinlivan     
All BW hulls are completely filled with foam between the inner and outer shells. The comment about fuller hull forms on the Conquest means that the hull is fatter in the front that an Outrage so that when the boats are floating it has more displacement in the front to support the greater weight in the front. The amount of foam in the hull doesn't have any effect on buoyancy unless you fill the hull with water. In that case if the foam occupies space that could otherwise be filled with water the boat will float higher.


DaveH posted 03-14-2004 01:45 PM ET (US)     Profile for DaveH  Send Email to DaveH     

Jimh meant that the outer portion of the hull is responsible for the displacment figure. (Think of trying to push an empty milk bottle under water. The shell of the bottle displaces water, creating a bouyant force) Remember, a hull's weight or displacement is equal to the amount of water weight it displaces. By tweaking the shape of the hull form, i.e. more volume of hull, you can add bouyancy to the bow.

This can be accomplished by designing less V shape and using more rounded sections in the bow, thus creating more bouyancy up front in the bow where the design needs it to counter the weight of the cabin.

Moe posted 03-14-2004 01:46 PM ET (US)     Profile for Moe  Send Email to Moe     
BeachPanda, you are confusing bouyancy when swamped (foam) with bouyancy when afloat and situation normal (hull form).

The amount of bouyancy under normal conditions depends on the amount of water the hull displaces with air (which includes air-filled foam) inside the boat hull below the waterline.

A boat with the weight of the cabin up forward needs to have a hull shaped to put more hull volume in the water up forward.

What the Whaler rep stated had nothing to do with foam at all. All Whalers have foam throughout the hull, including the bow, to provide bouyancy when the hull is full of water (swamped) and not providing bouyancy with air inside the hull.


Jerry Townsend posted 03-14-2004 02:07 PM ET (US)     Profile for Jerry Townsend  Send Email to Jerry Townsend     
BeachPanda - USCG flotation criterion require the gunwales remain level when swamped - therefore, if there is a bit more weight forward or aft, then there has to be more flotation in those areas - and consequently, a greater volume of foam between the two shells. --- Jerry/Idaho
Moe posted 03-14-2004 02:23 PM ET (US)     Profile for Moe  Send Email to Moe     
There is no USCG requirement for level floatation at the sizes of Whaler's cabin models. That only applies to boats under 20' long.

The USCG requirement for "level" floatation doesn't fit my definition of level. Only one end of the boat has to be out of the water and the other end can be 1' below that. Typically, it's the bow that's above water and the stern that's a foot below it with the motor submerged.

The National Marine Manufacturers Association is the one that requires sub-20' boats to have the whole length of the boat at the waterline. Given the depth of transom cut-outs, even these boats may have the powerhead at least partially submerged.


BEACHPANDA posted 03-14-2004 03:39 PM ET (US)     Profile for BEACHPANDA  Send Email to BEACHPANDA     
Thanks to all for the explanation. Like I said earlier, I'm not as knowledgeable as you, and my learining curve still looks like a hockey stick.

jimh posted 03-14-2004 04:57 PM ET (US)     Profile for jimh  Send Email to jimh     
Panda--as requested, you are forgiven for leading the thread into the desert for nine follow-up postings.

Back to the topic:

I found the notion that the hull form is tweaked for individual applications to be quite interesting. In the old days it was more of one-size-fits-all for the shape of the hull used in various models. You can certainly see the difference in the static trim of older hulls with Outrage fit-out versus, say, a Revenge fit-out on them.

I was assuming that the newer boats were being built in a similar fashion, and that there was a sort of generic hull and inner liner for certain lengths that was molded and assembled, then the rest of the boat fit atop it. Wrong.

Even the inner liners are quite unique and provide for much of the interior compartment detail and finish. Things like fuel tank cavities, cable pathways, and other details are pretty much unique to each boat.

In the older boats, the same liner/deck was used among many models. For example, the Revenge and Outrage again. In some cases, like for the step into the cabin of a Revenge for the companionway, they cut out part of the molded boat and set in a new laminated section, but otherwise the same deck liner component was used in both. Not now.

I was also surprised at the number of molds, because Boston Whaler molds are rather more elaborate than most other boat builders' molds. They have to be built very strongly to contain the pressure of the expanding foam without distorting the shape of the mold.

jimh posted 03-14-2004 09:59 PM ET (US)     Profile for jimh  Send Email to jimh     
Well, my apologies if somehow something made anyone on the planet think there was a hull void in a new Boston Whaler. I've been reading this over to try to figure out where that idea came from--all a misunderstanding.

Now, back to the new hulls...the void-free, foam filled, new hulls...

DaveH posted 03-15-2004 09:43 AM ET (US)     Profile for DaveH  Send Email to DaveH     

Like the movie "Flight of the Phoenix, let's pull this baby out of the desert.

In reading your article, I am curious if in your discussion with the Whaler people, they mentioned if they outsource a naval architect or they use in-house designers for the hull forms?

luife posted 03-15-2004 12:29 PM ET (US)     Profile for luife  Send Email to luife     
Hi, I'm new to this forum, and I think is one of the best web sites/forums I have read.

Regarding the new whaler hull designs, I'm really curious about DaveH question. The reason for it is that one thing that I really like about the old whaler hull designs is the quick planning ability and low RPM planning. Based on some reviews I have read about the new outrages and conquest, some of them start planning at 4000 and 4500 RPM. And, this is on 2 stroke engines with max RPM of 5500. To my, that is not an efficient hull. The construction can be the best, but if they don't navigate well, what is the point. This is just a thought of a Whaler fan and boat lover.

jimh posted 03-15-2004 07:44 PM ET (US)     Profile for jimh  Send Email to jimh     
I don't know all the credentials of the in-house design team, but at least one of them--Jeff who worked on the 320 Outrage--is a graduate of the University of Michigan Engineering School in Naval Architecture.

I am a little biased toward the University of Michigan--my alma mater--and especially toward the Naval Architect program. My college room mate was a Naval Architect major and graduate. The U of M has a great reputation in Naval Architecture. I think the last several America's Cup boats have been designed by grads of U of M.

So, yes, I am sure that Whaler has plenty of qualified in-house talent on these hull forms.

jimh posted 03-17-2004 08:34 PM ET (US)     Profile for jimh  Send Email to jimh     
[Extending my remarks, as the Senators say...]

One advantage to using CAD tools for design of these new Boston Whaler boats is the ability to use Finite Element Analysis (FEA) to look for stress points in the hull. This allows the boat to be pre-engineered for the forces that will act on it. The laminate schedule (the thickness and strength of the laminated structure of the boat) can be pre-engineered and designed appropriately.

In the early days of building boats from fiberglass reinforced plastics (FRP), no one really knew the strength of the materials or what stresses the hull form would generate. Builders like Everett Pearson built very thick sailboat hulls from FRP because it was not known what the real strength of the materials would prove to be. Modern design methods and greater knowledge of FRP strengths permit Boston Whaler to built their new hulls with the right amount of laminates in the right places. Thanks to sophisticated computer modeling and analysis, the guesswork has been eliminated. You don't have to build a boat with 2-inch thick laminate because you don't know how well it will hold up--you can calculate it in advance!

By the way, my old sailing club used to own a 1960's Pearson 26-foot Commander sailboat, whose hull was very thick fiberglass laminates. That boat was in service for 40 years as a training boat, teaching thousands of people how to sail, and the hull was as strong as the day it was built. Of course, it was probably three times as thick as it really needed to be!

That kind of extra weight is a burden to carry around in a modern power boat, so thanks to FEA, Boston Whaler can engineer these new designs to weight no more than necessary to provide the strength needed in the hull.

whalerdoc posted 03-19-2004 11:17 AM ET (US)     Profile for whalerdoc  Send Email to whalerdoc     
Not to lead this into the desert again, but did you perhaps inquire into the future of the cpd gaurdian line while speaking with the whaler reps? I remember a couple of years back there was much rumor that the guardian molds were going to be scrapped - then came a large US military order and they are still with us...
Moe posted 03-19-2004 11:38 AM ET (US)     Profile for Moe  Send Email to Moe     
Getting back on topic...

The 170 and 150 hull designs are virtually identical, with the 150 being the later design. I've found only one small difference, shown here:

On the 170, the sponson is carried all the way to the transom. The 150 looks the same as the 170 just forward of the transom, but in the last few inches, the sponson tunnel flares down to the transom where it disappears.

I'm sure there's a good reason for this, but it would really be interesting to know what the modeling software showed for the differences in performance or fluid flow around this area.


DaveH posted 03-20-2004 04:27 PM ET (US)     Profile for DaveH  Send Email to DaveH     
I totally agree with your comments about Univerity of Michigan. I was accepted into the Ocean Engineering program at U of M and considered going there back in the early '80s. It is a very good school for all the marine engineering programs (top 10 in the nation when I applied). I ended up accepting an invitiation to attend Florida Institute of Technology for Ocean Engineering. Have you heard from your old college roommate?
whaler3 posted 03-20-2004 07:36 PM ET (US)     Profile for whaler3  Send Email to whaler3     
JIMH I hate to bring this up but soon you will have to adress this problem. It is the owners of the post-classic Boston Whalers and the NEW WHALER hulls. You will have to start a new thread for the NEW WHALERS owners. Just can't see them all combined. (Just can't get ysed to the high sides, plus it makes it harder to boat a fish) Lou
Ed Stone posted 03-21-2004 08:56 PM ET (US)     Profile for Ed Stone  Send Email to Ed Stone     
The new 240 and 270 outrage hull share a few designs,
240 has 46 degree entry and the 270 has a 48 degree entry.
They both have 22 degrees at the transom.The same options
are available for seating.They both come with 23 gallon
livewells and a additional livewell with the optional
leaning post.

The 32 has a 23 degree deadrise at the transom and a
"keelpad that gets the stern up while getting on plane."

I'm trying to figure out who their target consumer is.
There is some tough competion out there today.If they go
after the hardcore offshore fisherman they have to build
a no holds barred ,hammer the throttles and never look back type of boat.

The previous Outrages lasted 4 to 5 years with 20 degree
deadrise.The new ones are 22 to 23 degree deadrise.How
long before the next generation of Outrages come out and
will they join the crowd of Regulators,contenders,seavee,
yellowfin and Mckee Craft with the 24 to 25 degree
transom deadrise.

I'm not sure thats the consumer group whaler is after.

Ed Stone

diveorfish posted 03-22-2004 12:16 PM ET (US)     Profile for diveorfish  Send Email to diveorfish     
This was the kind of conversation I was ineptly trying to start with the stability topic. If Whaler came out with 24+ degree deadrise hulls, would that be a good thing or a bad thing? All things are a compromise. What is the downside of a 24+ degree deadrise?
Peter posted 03-22-2004 01:02 PM ET (US)     Profile for Peter  Send Email to Peter     
Target customer seems to be someone who wants a blend between a SeaRay and a Regulator (or Contender, etc.). Just a guess but that target customer might be a "two headed" decision maker whereas the Regulator-Contender customer might be a single headed one.
luife posted 03-22-2004 02:19 PM ET (US)     Profile for luife  Send Email to luife     
I think that is one of the issues of the new hull designs. The high transom deadrise angle make them hard to plane, or high speed planers and as a result in rough seas you need to go fast to be on plane and probably that will be pretty hard to withstand (by the operator). Also, with that much deadrise, you loose stability. I think that the older hull designs were more appealing to more people because I've seen Contender kind of guy buying old Whaler hulls but I also have seen classic whaler hull fans going elsewhere because they don't like how the new hulls perform.
Ed Stone posted 03-22-2004 02:30 PM ET (US)     Profile for Ed Stone  Send Email to Ed Stone     
I am by no means a boat builder or naval architect.
The little I know comes from reading magazines.

I am just a average consumer(somtimes two headed)
that enjoys fishing offshore.Sometimes when I have time
to go fishing it's not the ideal weather conditions.
When your going fast and the water is rough somtimes
your boat re-enters the water near the the stern and
thats where the 24 degree deadrise would help.
From what I understand that 24+ degree deadrise will
need some help in the stability department while at
anchor,drifting or slow trolling.That is where
the chines are suppose to help with stability as
long as they are immersed in water.

Also to much deadrise can lead to more power needed
to get up on plane.Which in turn will make your hull
less eficient.Okay now you have a boat that will need
more power and with that the stuctural integrity of
the transom will come into question.Not to mention
the intial cost of the boat package rises.

I know whaler sells alot of boats and they do
alot of research as to whom will be buying their
boats.If I had to guess I would say the two headed
consumer or family buyers are their biggest group
of consumers.But remember todays innovations on
all brands of boats out there will be the standard
features that tomorrows boat buyers will demand.

Ed Stone

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