More Option One

Nomad,

Yeah, we have fishing tournaments here too that have boats trailed in. I haven't checked but don't think any of them are as big as 36 feet. Could be wrong though. The guys who bring them and the trucks used to tow the big ones are not like the average guy and his vehicle who is probably our target. I'm like the later group and have a great aversion to having a huge rig following along behind me. I've done it but don't like it.

I got a little wound up in my rant but still think that the simple approach is the best. My towing test model for study in designing "Liz" was named "Ocham's Razor", which kind of describes my view of most things.

I think it may be possible to push the concept I used to 27 or 28 feet but am not certain. I am perfectly happy with not having full headroom in the sleeping cabin as long as the bunks ar large and comfortable with full sitting headroom over. For me, there needs to be plenty of headroom in the main cabin though.

 

Tom I can see you point but what would look better a 28' boat with 6' 3'' head room or a 33'-36' boat w/6' 3'' headroom?

 

As always, I agree with much that Tom has said, but it is worth considering a few things before we consign the boat in its current form to the too hard to achieve scrap heap.
1st of all I don't believe that a deep V has to be heavy in order to handle well. For instance, Cigarette build a 36 footer with an 8' beam which tips the scales at 3900kg - heavier than we are aiming for, but this is a boat capable of belting through 6 footers at 90+ mph. Lower down the performance spectrum, R C Hunt & Assoc. (the "inventors" of the deep V) produce a 33 footer which manages over 30 knots with a single 315hp diesel. It does this by weighing in at 4500kg. Many 20+ foot ski-racing boats running in this country have deep V's - they're so light you can pick them up! Now all these boats are different to the one that we are proposing, but all are "light" compared to their competition - you get my point.
Further, I agree that nobody seems to have produced a 35 knotter capable of comfortably cruising 2 - 4 people at a reasonable cost. That doesn't mean it can't be done - and all the more reason for us to give it a shot. It may well require us to revisit some of our design parameters and adjust or scrap them as necessary - that's the whole principal behind the 'design spiral' - so long as we wind up with something which is true basic orginal idea at the end of it.

I like the idea of a 33 footer which I could keep on a trailer, but, like Tom I think that the practicalities of towing it around make it impractical - and expensive. There are indeed plenty of 36 footers which are regularly towed about, but most require a small truck to safely move them.

There is going to be a cost penalty involved in being capable of cruising at 35K. It's as simple as that, but I do believe it can still be done for far less than is generally the case in the production boat market. As I've said before, 450hp worth of the latest digitally controlled outboards, completey fitted up, including the very best of hydraulic steering amounted to under 50k AUD (25K USD). We've previously estimated that 300hp would serve our purposes. Now, I've owned a number of boats, but I've never built one - allow 10K for the trailer and incidentals. That leaves 40K (USD) for the hull - can it be done?

 

Nomad - here's what a 28 footer with over 6' headroom could look like.
It's only a "napkin sketch" so I hope it's not too scruffy for you guys!
3 permanent berths, separate head with shwr - full dining and cooking facilities. Length of hull 8m, 9m LOA. 2.5m beam, 2x 175 hp DFI o/b's.

 

Why 45 Knots

I guess I missed the post where you guys decided to go 45 knots.

When it comes to power boats you can go very fast or you can very far, but you can't go very fast very far. I'm more interested in going far and I don't have flat as glass water that will allow me to go fast without getting beat to #&@%.

The design compromised required to go 45 kts are quite severe. Since a trailerable boat can go 55 mph on the trailer I don't think it really needs to go 45 kts on the water.

Cheers;
Mike Schooley

 

Re: Why 45 Knots

Tell that to Fabio Buzzi

 

Mike has a valid point!

When you think about it in probably 99% of situations - a trailerable boat could be towed via roads at 90 km/hr to a better launch point more cost / fuel efficiently - than running extra distance there, bye water so - the need for speed is a debateable point.

For broad mass market appeal - maybe such speed over water isn't crucial.

I tend to think in terms of my own operational needs - and these two bays with mostly protected water are over 150 nm long each and 20 - 30 nm wide with no road to speak of (certainly not one you'd tow even a dingy on a trailer over let alone a large boat) - so speed over water does spell the difference between viable "daytrip fishing" to the extremitys of the area, or such voyages becomming "overnight" only propositions.

In that situation, speed over water counts as far as market appeal for fishing trips to distant spots with the biggest / best fish, but for someone out for a leisurely family cruise - thats not a consideration.

Now -as for the "build it yourself savings on labour..trust me from the excercise I've done wit my fiorst boat which was a build it yourself - you don't save much!

Now - news - both Merc and Yam are bringing out new midrange 4 stroke models - Yam in Aug 2002 - and Merc early 2003 - soooo...maybe we could save a few $ onn those factory rigged 225's bye downsizing a little?

Just thinkin out loud!

Cheers!

 

Very fast very far

I know Fabio Buzzi and nobody can tell him anything!

Lets take an FB design as an example. The 34 Superhawk http://www.sunseekerny.com/sh34.htm has; "Cruising speed 23 to 41 knots*", "Fuel capacity 700 Liters 185 US gals" and "Range up to 220 miles*". I don't consider this very far. That is 1.2 nm/gal. Of course this is probably based on the smallest engine option. Engine options go from two 230 HP engines to two 445 HP engines. At the high end the range and mileage will be about half.

Portager will be 36' and have a single engine <100 HP. At a cruise speed of 6.8 knots and 350 gallons of fuel, range is 3,500 nm. That is 10 nm/gal. I consider this very far. At my max speed of 9.7 knots, I'll have a range of 1,200 nm or 3.4 nm/gal.

If you assume that engine cost is proportional to HP, the engine for Portager will cost between 44% and 22% of the cost of each 34 Superhawk engine. I've budgeted $15K for the engine for portager. I'd say the 34 Superhawk is paying a very steep price to be able to go fast.

Cheers;
Mike Schooley

 

I think we get off on tangents that will not get us to the original goal which definitely did not include a 45kt speed. I have no quarrel whatsoever with anyone that wants to travel at this speed or cruise at 35kts, but....I am not personally interested in having a boat that does that WITH THE COMPROMISES THAT IT DEMANDS. Even if I wanted a boat like that, I simply cannot afford it, either in first cost, fuel use, maintenance or the attention that such a boat would require.

In just about every place we have cruised, if we go 100 miles in one day we will have passed by several places that are interesting enough to stop and experience. We usually cruise at about 13 to 15mph or so and get where we are going fast enough and enjoy the trip besides. I used to fly across the water at whatever top speed my boat would take me but I only enjoyed the thrill of the action and not the place. Today, the PWC fills that need and, as much as I dislike the things, I probably would have been attracted to them then. In a cruiser, I simply cannot see the need or attraction for that much speed.

Many of the cruisers that I know (living where I do, there a whole lot of them, power and sail) spend too much time, money and mental anguish in maintaining their toys. I'd much rather think, design, build and use the boats I have than be married to one of theirs.

I do tend to run astray between what I want in a boat and what the market wants. It seems certain that the market wants more speed than I do in a planing boat. On the other hand there are an awful lot of slow displacement "trawlers" sold.

Of course, Nomad, it's true that a 28' boat with standing headroom is easier to make good looking than a 24' one. No argument about that.

What I said about deep V's and displacement is based on the following: In order for a V hull boat to handle well, the aft chines MUST remain immersed at all times. In order for this to happen, the weight must be sufficient to immerse the chines at the dock and at speed. Based on that truism, a deep V simply cannot be designed as light as a boat with a shallower V aft hull. I'm not talking about any specific boat, just a rule of design. "Liz", at her displacement can only have a deadrise of 10 degrees and no more. More deadrise would undoubtedly make her ride smoother in waves but would be detrimental to her lateral stability which is a safety and comfort issue.

Every design parameter is tied to the others. Emphasizing one will always affect the others. This is easy to say, but also easy to forget when you are coming up with your wish list.

 

A couple of questions...

and suggestions...

1) who said it had to be a monohull ?

2) Trailerable - do we have to consider this as living on a trailer and always on the move,.. or can we consider this as "can be moved by trailer" that way when we want to move to a new cruising ground we could put it on the trailer, borrow a truck and take it - for people that dont plan to always live in the same place - or people that move with the seasons... Length would be less important - but would still have to be legal to trailer

2) 50K could be the price for the base 28 knt model with a good level of finish. The same hull could be rated up to the required HP to make it pull the 45knt bit. - wider market - after all look at the car (and boat) manufacturers

Option 1 SB - 50K

Option1 GSXi - 80K


Just an idea

Paul

 

Wow Paul!! I like both ideas the boat never was said to be a mono, and I especally like the model idea. Good thinking.

 

This is some good stuff guys!! And whoever siad eariler in another post the best is yet to come is right!

 

There is a place for boats with cruise speeds from anywhere from 3 knots to 73. If I cruise at 35k I too will pass by any number of nice anchorages in an hour or two's running. But they are places that I've been visiting for 30 years in boats that operate in the 8 to 20k region. A high cruise speed allows me to travel to those locations which are further afield - places that other boaters rarely get to. In Tassie there are no roads to allow me to travel "at 55 on the highway" till I'm nearly where I want to go - besides, if I wanted to do that I'd buy a camper!
Option One - to me at least - started out as an experiment in "design by committee" - with no hard and fast rules as to what sort of boat we are supposed to be creating. That has evolved as we have all voted, into a 35k, trailerable cruiser. I'm not likely to build such a boat - It won't offer me enough to make it worth changing from my current boat. I would suggest that few of us are likely to - That's not to say that I wouldn't like the concept - and certainly that it isn't a worthwhile design exercise. If we are each going to give up as the boat evolves into something that doesn't fit our own requirements then we may as well scrap the idea right now.
However, if we come to the conclusion that any one design parameter is unachievable, then surely the sensible thing to do is re-visit that particular poll and re-assess. I'm not sure that we've reached that point yet - though it's bound to happen a number of times before we're done.

 

High / Low Power

I second the two speed approach. With high and low power options you can broaden the market appeal. It does however mean that the design needs to accommodate the weight range of the engine choices. This is easy to do with an inboard where the engine(s) is(are) located at the center of mass, but it will require a balancing act with outboards. Won't the mass difference affect trim?

Personally, I'd like to see the low speed option be a displacement "Trawler" and the high speed option be a semi-displacement boat. If you good with a true planing design you need to make sure the low power option has sufficient power to remain on step going against wind and waves. There is nothing worse than an under powered planing boat.

The problem with multi-hulls is they tend to want a lot of beam which would be a problem to trailer unless you provide folding structures, ... In addition multi-hulls tend to provide a harsh or jerky ride in beam and quartering seas. They are fine on flat water, but the Pacific Ocean is rarely very flat and we don't have an inter-costal waterway on the left coast. Just my ¢¢.

Cheers;
Mike Schooley

 

I know, I know - getting way ahead of myself again - but you can't blame a guy for being enthusiastic.......