Trailerable Sports Cruiser


Thought some of you might me interested in my latest project sketches.
(full size versions can be seen by clicking on the images)
I am designing a fiberglass sports cruiser boat for my final semester project.
The primary elements of the brief are to maximize deck and cabin space while keeping the boat towable.
I have placed the cabin entry at the rear center of the boat because I believe I can fit the two smallest sterndrives required for the axius system on either side of the entry.

The final image was my first attempt at a photoshop rendering of one of my sketches, it doesn’t represent my design.
I attempted to replicate some of the feel of these sketches:

I am modeling it in catia and its my first attempt at using the surfacing tools.
Rather daunting, does anyone have any advice on where I can find information on the “Automotive Class A” workbench in catia?

In case someone is looking for information on the sweep tools, this is an amazing set of tutorials and I am indebted to Adam.

Keeping the skillset comments aside, I have a few questions regarding the actual design.

#1: Your scale looks off. The boat looks too ‘chubby’. The top views are fine, but you get to that side profile and it looks entirely too tall.

#2. How big is this boat? Looking at the scale of the chair in the rear render, this must be a 45’+, which I would hardly classify as towable.

#3. What is the weight you are trying to stay under? All that fiberglass adds up quick, which adds to the problems with towing.

In short, I think you need to do a quik dimensional drawing so we can have a better idea of scale/proportion. I have spent years towing boats and large hoist (nothing like carrying a 12’ wide hoist down a 10’ road), and as soon as I saw these I knew I would not want to take it. Also consider that the taller the boat is the higher the center of gravity. You want to keep the weight as low as possible to avoid a roll over. Trust me, you dont want to clog a busy intersection because you tipped a boat on its side (the police dont like it either!)

As with anything, context is everything! Who is this for? What will they do with it? What else is important in their lives? and what is the current market competition?

Is this better than what is out there from a consumer relevance point of view functionally and stylistically?

If towing it is a key parameter (the only you have mentioned) why not design a trailer as well?

Sketch wise, I think you have to be more in this zone: reference is so important:

A good example of a page with dimensions and human scale:

While the exterior has all the glory, most of the real design innovation is going to be inside:

Joyride I totally agree and its been pointed out by others.
I think it is just my sketching letting me down but it may not be a feasible design.
I did a pile of rough sketches and measurements and I believed the scale was correct but now I doubting it.

The boat is drawn to be 26’ (7.9m) long, 8.5’ (2.5m) wide and 12’ (3.6m) high.
The chair in the sketch was meant to be roughly 1/4th of the boats width making it 60cm wide.
I thought I would have some flexability with the boats height because of the weight of two sterndrives (roughly 1 tonne) down low.

If the trailer weight is taken into account (approximately 0.5tonne) that leaves me 2 tonne for fiberglass and fittings before reaching a maximum towing weight of 3.5 tonne.

Thanks for the links yo!
I love the two 116’ concept renderings (1, 2,).
I am really impressed with these pieces of work, and they both include ppl for context.

I did entertain the idea of designing a boat trailer, but after interviewing a major retailer here they said that for the most part boat companies avoid designing trailers because of the vastly different requirements internationally. Generally the boats are designed for an international market and then the trailers are produced locally.

There is a fairly comprehensive brief and hypothetical persona but the key elements are that the boat come in close to $100k, include an enclosed toilet, a fridge, have a large amount of deck and cabin space and be trailerable.
It def has more usable deck space and cabin space due to its height than anything I have found so far in this size of boat. However that relies on it being feasible to have the dimensions I have chosen.

The interior is going to be challenging, but that can wait until I have a hull design to work within.
Cheers for the replies!

I would personally be a bit careful with this, are your external dimensions driving the overall design or is there some flexibility in regards to dimensions due to the interior requirements (toilet, cabin, etc)?

To me it seems that most heights of boats would be close to half of what your suggesting, which may explain your proportions, is there a functional need for this height? (most residential ceiling’s are 2.7m), also, another thing to consider is that once this thing is on a trailer (add an extra 1m) is it going to fit through a tunnel? maybe turn your canopy into something collapsble? (may help with aerodynamics also) Just some thoughts.

I think your presenation is clean and looks good :slight_smile:

Hope it helps.

I don’t want to dwell on the lack of fundamental skills but instead give you a decent roadmap of how to design a boat. You already have some dimensions and a power source that you believe you would like to use. I am going to assume that you have already benchmarked other boats within this class. You should probably start off by using an existing boat within this class as an underlay so that you can get you proportions right. Draw up as many little thumbnails that represent the profile of the boat as you possible can. Just remember to keep it within the correct proportions. Once you find something you like do a package drawing. From stern to stem this should include engines, fuel tank, mid ship bulkhead, interior accomodations, and anchor locker. This will give you a decent idea of how much space you have for interior accomodations. Now you can create your hull so that you can determine what kind of interior beam and deck space you will have. You will not have a whole lot of space on a 26’ boat. As you create the interior and the deck keep in mind where your center of gravity is. Where you currently have the helm deck is probably too far aft. This would create all sorts of negative running characteristics. If you stick to the proportions of current models in this class you should be pretty safe. So create a decent plan and profile view that you can work from that outlines your space allocation. Now as Yo said, determine how you are going to differentiate your design from everything else that is out there. Space utilization is not enough in this market, it is a big part, but it’s not going to make people want to know more about your design. Also as Yo said exterior styling is not everything, consider functional uses of space and features. From here just keep coming up with ideas and refine your design. Sorry for the long post but it was necessary.

The external dimensions are being set by the legal towing dimensions locally, although its possible to get permits to exceed them I was hoping to make my design work within them.

Wow thanks for taking the time for the long post Charlie!!

I started off using an underlay to determine sizing but I gradually extended further and further from those dimensions.
To be honest I didn’t know how far I could push them before they became ridiculous, I guess I found that point. :slight_smile:
There is a high likelihood that I used one of your designs as an underlay, The boats closest to what I was aiming for were all made by Brunswick, the Bayliner 285, Maxum 2700 and the Searay 260 and I used the bayliner 285 as my initial underlay.
The height of the boat sketch not including the canopy is roughly the max height of the canopy on the bayliner.

Are running characteristics the same as trim?
Should the center of gravity be over the center of a boat’s planing surface or near the center of the hull?

I was planning on moving from this point and designing the interior while modeling up the hull but its obvious that the dimensions and layout of this are not workable atm. I will def do a set of package drawings before continuing and review how the hull shape will work from there.
Finding the balance between the exterior shape and interior layout is very similar problem to neither styling or utility being in themselves enough to grab ppls attention, its somewhere between the two.

Your the second person to avoid commenting on “skillset” or mentioning “fundamental skills”.
Are there critical sketching and representation skills that you believe I need to develop above others?
I am drawing close to the end of uni and it would be great to know what I really need to address and prove before I have to show work for an internship or potential employer.
What does Brunswick and what do you look for in graduate designers?

Finally out of curiosity how much time does the design phase for a boat like this take at Brunswick?
I noticed that you both sketch and model your designs, do you also do the drafting for boats and at what point does the hand off between designers and the rest of your teams happen (product development, engineering, drafting, materials, etc…) ?

Sorry for the 20 questions & thanks again for the reply!

I understand your dimensional constraints, it’s always something that has to be dealt with in this size of boat. But if you are going to make it a trailable designer think about how someone who trailers their boat uses it differently than someone who moors it or stores it on a lift.

As far as running characterics go they would include how fast the boat gets on plane, what it feels like when you are turning, how dry or wet of a ride it is(meaning how much spray comes up the hull sides and hits you in the face), how fast it is, what the running angle is. Trim just refers to the angle the boat is running at.

Center of gravity doesn’t really have a magic formula, it is based on each boat, it all depends where the weight is distributed. The main items, but not the only, that contribute to COG on this size of boat would probably be engines, generator, fuel tank, and water tank. I wouldn’t worry about these items too much but if you do a package drawing that shows you understand the mechanical constraints around designing a boat of this size shows perspective employers that your design is not just about some facade. Use some existing boats as reference and you will be good.

Alright now skillset. I looked through some of your other work and I thought it was a much better representation than this project. Your modeling and rendering skills seem to be really good. Your sketching skills are leaving a bit to be desired. There are some general perspective issues that could be resolved. Where to stress line weight and where not to. But looking through older forum topics these have all been brought to your attention before. Boats are not easy to draw because a lot of the curves are moving in two opposite directions at any given time. Makes it difficult to draw in perspective. So saying this and understanding your skill level I would recommend looking at other designers and try to pick up on what they are doing. Understand how they use perspective, line weight, and stroke to make their designs visually appealing. It looks like you are overworking the designs a little bit. Loosen up a bit and make smooth lines that extend past where you want them to start and stop. You don’t have to include every detail at this point.

Alright I can’t type anymore, we need to make these shorter posts.