Mid Size Power Boats

Mid Size Power Boats

A Guide for Discriminating Buyers

by David Pascoe

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Chapter 6

Performance and Sea Keeping

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Table of Contents

The Meaning of Sea Keeping
Juggling a Host of Factors
About Speed
Hull Types and Efficiency
Vertical Center of Gravity
Passenger Height Above the Water
The Effects of Trim
Shaft Angle, Propeller Pockets and Vee Drives
The Effects of Beam
The Effects of Weight
Dynamic Instability - Chine Riding
Extreme Cases


In this chapter I'll discuss some of the critical reasons why it's not a good idea to just go out and buy whatever looks good to you stylishly, or simply fits your needs in terms of that wonderful cabin layout that Mrs. Boat Buyer dearly loves. In fact, you may want her to read this chapter, too.

The two big reasons why so many boat builders can get away with creating such terribly performing boats results from (1) a majority of new boat buyers are inexperienced, and (2) no matter how much boating you do, few people ever get the opportunity to actually operate, under adverse conditions, more than a few boats throughout their entire boating careers.

Thus, the "average" boater never really learns the difference between good and poor handling boats, particularly since most of the really good performing boats are in the sport fishing category.

My purpose in this chapter is to get you to think a bit more carefully about the performance characteristics of the type of boat you propose to buy through a discussion of what accounts for both good and bad performance.

Moreover, if you have any notions that the boat you buy will only be used on nice days when conditions are favorable (that's a rationalization I hear at least once a week), I'm suggesting that you rethink that idea carefully. ?

The truth is that reality rarely cooperates with that notion, leaving the boat owner, more often than not, disappointed with his very expensive choice.

If you've ever walked through a boat yard, you've probably noticed that boat hulls come in an almost infinite variety of shapes and sizes.

Hull shape is responsible for a wide variety of performance characteristics, and there is no one hull type that does everything equally well. Therefore, we don't want to end up paying a lot of money for something that does not meet our expectations.

Since there are numerous factors that combine to make for either good or poor performance, it's best to avoid drawing simplistic conclusions.

Indeed, when we use the term "good performance," we are referring to many factors including things like good fuel economy, the ability to handle a rough chop without pounding, rolling motion, pitching and dynamic trim among others.

We should also understand that perceptions of sea keeping ability will vary depending on operator skill.

A highly skilled pilot can make good with the worst of boats, whereas the unskilled pilot is likely to have great difficulty. Thus, when considering sea keeping, bear in mind that much depends on boating skills.

For example, in one of my published boat reviews, I stated that a particular boat had fairly good sea keeping abilities.

An individual went out and purchased that boat based on my review. Shortly afterward, I received an e-mail from the person taking exception to my evaluation of the boat. The new owner stated that he found the boat almost impossible to control in a following sea.

Not understanding why his opinion and mine were at great odds, I called the man and discussed it with him.

It turned out that this was the first boat he had ever owned, and that he had never taken a piloting or seamanship course. He had a problem with broaching in following seas because he was operating the boat too fast for the conditions.

Broaching is the situation wherein when you bury the bow into the backside of a wave, it forces the boat to veer off, often uncontrollably. I had to explain to him that virtually any boat will broach in high following seas if you try to run too fast. His problem was one of a lack of experience, not poor hull design. Almost all boats will behave this way under such conditions.

cover art: Boat two bows Mid Size Power Boats
- A Guide to Discriminating Buyers

Soft Cover
512 pages
Publisher: D. H. Pascoe & Co., Inc.
Published: 2003
Language: English
ISBN-10: 0965649636
ISBN-13: 9780965649636

Price: $24.50
In Stock



David Pascoe - Biography

David Pascoe is a second generation marine surveyor in his family who began his surveying career at age 16 as an apprentice in 1965 as the era of wooden boats was drawing to a close.

Certified by the National Association of Marine Surveyors in 1972, he has conducted over 5,000 pre purchase surveys in addition to having conducted hundreds of boating accident investigations, including fires, sinkings, hull failures and machinery failure analysis.

Over forty years of knowledge and experience are brought to bear in following books. David Pascoe is the author of:

In addition to readers in the United States, boaters and boat industry professionals worldwide from over 70 countries have purchased David Pascoe's books, since introduction of his first book in 2001.

In 2012, David Pascoe has retired from marine surveying business at age 65.

On November 23rd, 2018, David Pascoe has passed away at age 71.

Biography - Long version