YANMAR Technical Review

Abstract

Recreational fishing boats make up the mainstay of Yanmar’s pleasure craft. This product range has been shaped by market demands, with the focus in recent years being on the development and marketing of fishing boats that deliver a more comfortable experience. This has led to the new category of “fishing cruisers” that continue to grow in popularity.

Yanmar offers three models in this category, all in the 30-38 ft range. The 33 ft model was the first to be developed and, having already been on the market for more than 10 years, is now starting to see a falling off in sales volume.

Yanmar has also been responding to market demand for improved comfort by developing technology for this purpose, some of which was described in a previous YANMAR Technical Review report on “Wakuwaku-Boat Technology”.

This report describes the new EX34 pleasure boat that replaces the EX33 and incorporates the technical developments of the Wakuwaku-Boat.

1.Introduction

The EX33 went on sale in 2009, featuring a largest-in-class cabin in order to satisfy market demands that emphasized comfort as well as suitability for fishing. The model established the category of “fishing cruiser” and underwent a number of minor upgrades, including the addition of a version with a flying bridge (FB). The development of its replacement, the new EX34 model, was based on the concept of creating a next-generation fishing cruiser, and set out to overcome some major challenges with further enhancements to a variety of performance criteria that included comfort and cruising performance.

To achieve this, the development adopted a core design strategy of incorporating technical developments from the Wakuwaku-Boat along with the technologies honed on past EX series models.

• Enhanced cruising performance and quietness
• Improved styling and interior finish
• Attractive equipment

2.Product Overview

2.1.Styling (Fig. 1)

2.2.Specifications (Table 1)

2.3.Engine (Table 2)

3.Incorporation of Technology and Resulting Benefits

3.1.Enhanced Vessel Handling and Quietness

(1) High-rigidity hull

Market demand to minimize the impact that occurs when punching through waves continues to rise year by year, with this model being no exception. Along with the model upgrade, the new vessel incorporates hull design changes from the Wakuwaku-Boat technology development, including aspects of its high-rigidity hull. The benefits of having a highly rigid hull were described in the report on Wakuwaku-Boat technology that appeared in a previous edition of YANMAR Technical Review. The main advantages are:

• Rapid damping of impact acceleration
• Lower noise levels

A sandwich structure was adopted that is produced by vacuum infusion process. However, because its use for the outer shell of the hull underside in production-model vessels also needs to allow for boat fit-out (especially on-site fit-out), it was decided to only use vacuum infusion process for the base of the bow berth section, where it would do the most to minimize the impact from punching through waves (see Fig. 2).

(2) Matching with new 6LY440J engine

The 6LY440J electronically controlled engine for the Japanese market was selected for this vessel. It is the second such electronically controlled engine from Yanmar. The new engine provides enhanced practicality including improvements in trolling performance and the prevention of black smoke as well as its higher output and quieter running, with major benefits also being achieved by matching the engine to the new model hull, which has been upgraded and modified.

[1] Higher output
While higher speed is among the market requirements for the vessel, changes such as the larger FB also tend to make the new model heavier than its predecessor. As the choice to use the new engine was made early in the development process, the developers sought to increase the vessel speed by increasing engine output and matching it to the new model, as well as by reducing the hull weight. The end result of this work is a boat that is significantly faster than its predecessor (see Fig. 3).

[2] Quiet running
The noise level on the new vessel is 2 to 5 dB(A) lower than on its predecessor thanks to making the engine quieter, noise-proofing in the hull, and the high hull rigidity described above (see Fig. 4).

3.2.Improved Styling and Interior Finish

Along with making the new model available in FB and HT versions like its predecessor, the new model was also given a new design to accompany the enlargement of the FB to allow for more passengers. The FB was redesigned with a sense of spaciousness similar to that of a wide-hulled vessel, and modified to allow for the installation of Yanmar’s own seats (see Fig. 5).

In the cabin interior meanwhile, because of the positive customer feedback received about the seating layout on the previous model, the shape was left unchanged and the visual appearance was instead enhanced by changes to the upholstery color scheme and materials. The interior was given a fresh feel by choosing a color scheme with white as its base color, accented by black and dark brown (see Fig. 6).

(1) Changes to interior finish

Drawing on experience from the Wakuwaku-Boat, materials that combine light weight with rigidity were chosen for the berth space in the production model. The space conveys a sense of being well cushioned, and was made welcoming by giving it a feel unlike that of FRP panels (see Fig. 7).

(2) Enhanced convenience

Weight reduction was a requirement for the decking used in the berth space and the material used to fill the fixed seats in the cabin because of the need for these to be taken out and reinserted when stowing items. This was achieved by adopting a new material with a honeycomb structure (see Fig. 8), enhancing convenience by making these parts lighter.

3.3.Attractive Equipment

Although the interior layout was left unchanged, the visual attractiveness of the equipment was enhanced by the use of analog dials and a stylish steering wheel for the helm as well as by changes to the seat and cushioning to provide a more comfortable space (see Fig. 9).

The new model is also the first to come with air conditioning as a standard feature. This is available as two different options to suit different modes of use: either electrically powered for those users wanting to stay over at marinas, or powered by the vessel’s engine for users wanting air conditioning when fishing.

4.Feedback and Market Performance

A prototype of the EX34 was exhibited at the 2017 Japan International Boat Show. Market reaction was positive, helped by there being no other vessels in the same class available in an FB configuration. The EX34 subsequently went on sale, initially in the FB configuration only, with sales commencing at the 2018 boat show and the HT model being added to the range in the following year. The EX34 has also been recognized as a fishing cruiser, winning the 2018 Japan Boat of the Year Award in the Fishing category at the 2019 boat show.

A total of 17 vessels were built in the year from June 2018 (when the EX34 first went on sale) to June 2019, and the level of orders remains strong.

5.Conclusions

The EX series is the mainstay of Yanmar’s current range of pleasure boats. A number of major challenges of a type not encountered before had to be overcome in the development of the EX34, which serves as the centerpiece of the fishing cruiser category in Yanmar’s pleasure boat range. There was also a recognition that ongoing technology development would be needed if these challenges were to be resolved. While a number of these technologies unfortunately failed to make it onto the production model, Yanmar intends to continue developing products that keep pace with changing market requirements and the technologies that make this possible.

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The original technical report is written in Japanese.

This document was translated by Research & Development Management Division.