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View Full Version : Seajay 4.55 Territory and the F70A



Kondo 1
05-08-2011, 08:46 PM
Gday Guys,

Well in the past few months there have been a few threads here and there on the 4.55 Seajays and higher horsepower. Anyway cut a long story short I had my 12 month old Territory re-plated a few months back and just got around to swapping the F50 for the F70 last week.
I thought I would do a little report for people who had been interested.

Essentially my territory is far from standard, I do carry some gear plus I have the underfloor fuel tank etc and with the F50 I felt in my case that performance was somewhat pedestrian... Now I have to qualify this somewhat, my last boat (which is still in the family) was a 4.1 Brooker Fisherman with a 3 Cylinder 50hp 2 Stroke yamaha - clearly overpowered (not by my doing - bought it that way) and probably illegal/uninsurable but I did love it. It went really well if a little scary if you weren't paying attention or somewhat inexperienced. Additionally I did play with motor heights and props plus a permatrim on the F50 and whilst I did experience gains of varying degrees with some of the changes it just didn't satisfy me.

I felt in my case the (whether justified or not) that the F50 was not enough for my situation...

Anyhow I felt I had a few choices, the F60, the BF 60 and the F70 - whilst price was a consideration it was not a driver (and really if cost was then I would not have gone this path at all) so the F60 was ruled out off the bat, whilst a lovely motor if I was going to spend the $$ I would not have been satisfied with the F60. The prop size I think was a contributor to some of my issues initially and if I could have an F70 over it then why not. The BF60 was a consideration, I have heard some good reports and really I like honda gear in general and had a great run out of '98 15hp I had on my first boat. Additionally I liked the technology - O2 sensor and BLAST plus the bigger prop really appealed to me. The performance reports indicated it would probably perform almost as well as the F70 with probably using slightly less fuel.

Then came the F70, now here I had heard mixed reviews on its benefits, however one of my fathers colleagues has one on his 5+m platey - obviously far heavier than my boat and the performance he experienced was probably about lineball or slightly better than my territory with the F50. It was my assumption based on this that that meant it was highly likely the decreased weight in my boat would likely give me the performance I wanted...

In the end it came down to pricing and dealer relationships, pricing turned out almost identical and the Yamaha dealer I have always had good experiences with and I dont know any Honda dealers so decided to go for the F70.

Now firstly I need to point out that my boat is outside the Australian standards with the F70 however was assessed on its individual merits and was ok'd however did have some of the carrying capacity reduced - which didn't affect me. So some boats maybe wont get 70 etc.

First thoughts after a quick hour long run - great, out of the water it is markedly better, not by a huge amount but it is better. The sort of maneouvering speed of say 15-20 knots it is much better (staying out the hole and having nice pickup), certainly much torquier and the larger prop surely has a big part to play here too. Cruise is now 25knots a very comfortable 25 knots doing about 5000rpm using 1L for every 1.8 nautical miles. Flat out is 31 knots for about 1.35 miles to the liter at 6100 rpm.

This is with the standard 15 inch alloy prop and the motor on the bottom hole, ventilation is not a real issue - I mean you can make it happen but its not an issue... Also these figures are with a full tank, 2 big blokes and afull live bait tank and full fishing gear complement.

Interesting I felt the hull worked allot better with the higher cruiser speed, at 25 knots it felt still very solid in the water, tracked very straight and displayed no ugly tendencies (was no different flat out). Really I felt it could generate some good lift through the reverse chines and really make some real use of them... The ride through reasonable river chop was far far better at 25+ knots than 18-20.

Now one major difference between the 50 and the 70 is the torque evident through the tiller, by no means is it too much - but it certainly is there, proper trimming and use of the steering damper makes a big difference. However now this probably isn't a boat that you would now throw someone that wasn't used to a big tiller or definitely a novice. I find it really really nice and I feel far more confident having the extra sting that I was missing...

Overall, I am very happy - economically it was probably not a great decision, I did lose some $$ on the changeover I will never recover, though this boat will stay with me for a long time so that really dilutes the $$ loss for me and I went in knowing that. Certainly this conversion isn't for everyone however I wanted something I was satisfied with and I now am - it is a different boat and pretty well perfect for what I want.

I still have a ways to go, I think it needs a permatrim and I will be playing with some props over the next few months to see if I can get a bit better performance but overall very happy.

NAGG
05-08-2011, 09:04 PM
That F70 is a hell of a motor & not sure what would match it in that class ..... I doubt you would have done any better with any other brand for a 70ish - I've seen a couple of 60s change to the F70 and gain 10-15km/ph - but the hole shot was blistering
correctly propped - that 455 will fly

Chris

Kondo 1
05-08-2011, 09:10 PM
GDay Chris,

Not that it proved be a difficulty but I was restricted to the weight (the territory in my opinion wont support any more weight on the transom even if it was allowed) of the F70 BF 60 etc.

I am damn happy and just look forward to finding the right prop - thinking about trying one of the new yamaha performace stainless props, price wise around $500 I hear, traditionally I have used solas props but may give this a crack for something different.

You are right - it is a damn nice motor :)

rocklobster
07-08-2011, 07:37 PM
Hi Chris ,
Does the F70 have the new Plasma fusion bores like the new Yam offshore series?

NAGG
07-08-2011, 08:25 PM
Hi Chris ,
Does the F70 have the new Plasma fusion bores like the new Yam offshore series?

I'm not sure ..... I thought that the plasma fusion was only on the V6s

Chris

tonyp
07-08-2011, 08:40 PM
I reckon the Etec 75 would have been a good choice for weight !

NAGG
07-08-2011, 09:44 PM
I reckon the Etec 75 would have been a good choice for weight !

Hi Tony

This is one time that the ETEC is beaten on power to weight ........ The ETEC 75 suffers from about a 22% weight penalty for around a 7% gain in power
This F70 is a awesome little 4 stroke.

Chris

Kondo 1
07-08-2011, 10:22 PM
I reckon the Etec 75 would have been a good choice for weight !

25 Kegs heavier?? Whats the point??

I was limited by weight anyway - the surveyor clearly knows what he is on about, but say he gave me an extra 5hp and and 25 kegs, an E-Tec would not have been on my shopping list.