Beginner needs help finding a manual for Yam 55 BET

[m4inbrain]

Okay one stupid question.

What kind of speed (roughly) would one expect with those 55hp on a Shetland 535? Our speedo is broken (beyond repair), need to get a new one - the old one went up to 14mp/h. I don't care for speed, really - i just want to know what kind of speedo i'd need to buy. 14mp/h to me seems quite low.

The speedo wasn't connected to anything either, no pitot anywhere, so i don't know with what kind of engine he ran that (there was a 40hp one before the 55hp, and i assume something before that too).

[cpostis]

Okay one stupid question.

What kind of speed (roughly) would one expect with those 55hp on a Shetland 535? Our speedo is broken (beyond repair), need to get a new one - the old one went up to 14mp/h. I don't care for speed, really - i just want to know what kind of speedo i'd need to buy. 14mp/h to me seems quite low.

The speedo wasn't connected to anything either, no pitot anywhere, so i don't know with what kind of engine he ran that (there was a 40hp one before the 55hp, and i assume something before that too).

Tried to find some info on Shetland's website

Shetland Boats > Shop > Contact Us

Have to register to be a member at a fee to download info (what info available, don't know).

Maybe you can reach them to get an idea of expected speed with what you have. Maybe the specs will give you the information to estimate expected speed? Many variables to consider (WOT rpm, prop pitch/diameter, HP, weight of hull, engine, passengers, gear, hull type, etc.).

I've always been told that any gauge usually reads best at 75% of full range. So if you expect 22.5 mph, you should have a speedo that maxs at 30mph.

[cpostis]

Here's a link to get to a Yamaha Performance Bulletin on a boat very loosely like yours. Your boat looks like it would be much heavier than this, so max speed would be less.

http://yamahaoutboards.com/sites/def...saddc5.tmp.pdf

Once you get your motor running at peak performance and in the water, you should do a few things to make sure it is propped right. Mainly this is to see if at WOT the rpms are in the max range for your motor.

To be continued...

[m4inbrain]

Personally, i don't expect anything - i'm literally clueless in that regard.

Had a look around, other people with similar engines (+-5hp) reported speeds here and there, i just take an "optimistic estimate" and go with it, getting a 35mp/h speedo. Reported are between 20 and 25 knots, so that'll do. It's gonna be used as a fisher, not as a speedboat constantly going WOT, so all good.

Thank you though.

edit: yeah, it's a bit heavier. Roughly double, i think - should be around 600kg dry, 700kg with motor (1500ish lbs).

[cpostis]

Here's a couple of videos you may like:

https://www.youtube.com/watch?v=6f0sUMEfndk
https://www.youtube.com/watch?v=c5LpLGsRLTU

[cpostis]

How's your project doing? Got an update for us?

[m4inbrain]

Well yeah, there's an update.

The engine runs well now, took a while to sort out the electrics, source a second small motor as backup, get the console right, fix the trailer, rebuild the controls etc.

But here she is:

http://i.imgur.com/UHcg3QH.jpg (no idea why the forum isn't resizing, it's too big to embed)

The keen eye will spot that thanks to british speedbumps, we actually lost the front wheel of the trailer (hit a speedbump twice). Was quite the journey, hehe.

We didn't launch her yet, that's coming on the weekend after this one (weather not good enough this weekend). But everything's working, she's waiting in storage now to get her "maiden" voyage. Which will be fun, never launched a boat before - it's kind of a "hold my beer" kinda thing.

[99yam40]

Looks like not enough water around there to float the boat.

You have some wide tide swings over there.

Take a video of the maiden launch, it should be interesting for all of us to see

[m4inbrain]

Yeah, the water actually goes pretty much up to that street on high tide judging by the seaweed - but the ramp to launch it is 100m down the road, not steep enough at that position i don't think.

And video, well we'll see if there's a pair of hands free to film the impending disaster. Thankfully only once for now, it'll stay in the water for a while after that at a mooring.

[pstephens46]

Yeah, the water actually goes pretty much up to that street on high tide judging by the seaweed - but the ramp to launch it is 100m down the road, not steep enough at that position i don't think.

And video, well we'll see if there's a pair of hands free to film the impending disaster. Thankfully only once for now, it'll stay in the water for a while after that at a mooring.

Don't forget the plug!