small motor on 23 foot huntsman

[39NESP]

does any one run a small motor on 23 huntsman say like 50-60 hp

I have a 23 huntsman with a pod and would like to put small motor on

I am after about 12 knots

any cues please

[Noelm]

I guess the first question that comes to mind is WHY?? but if you really must, then a small motor with the right size and type of prop will do what you want, I once fitted a 70HP Johnson to big Cabin Cruiser type of thing that had a big 4 blade low pitch prop, and it went as the owner expected, gave him about 8 to 12 knots easy.

[Crocodile]

Why stop there?
If you fitted say a 140 hp motor you be able to plane, just, at full throttle, which could be very handy for short periods, eg. crossing a bar.
The rest of the time go easy at 8 knots with a very low reving motor to listen to.

[gone_fishing]

have a squiz through places like boat point
see what others are running on simlar size boats
give em a buzz see what their opinions are
i personally would look to the higher end of the hp range of a boat for more useability
hope this might be of help any ways

[FNQCairns]

Interesting idea, would be very hard to choose correctly the hp that would make an individual most happy.
No matter what ensure it reaches the top of it's wot rpm, the engine then wouldn't know if it is on a 5m tinny or a launch...apart from the hours running time.

At what speed do these thing start to drag their bum and point their nose up in the air? the spot where it leaves displacement mode and tries to plane, small hp 40hp? may get it there but to go much further you may need trebble.

would be interesting to hear how you get on, I have thought of doing more or less the same thing to park it for a few days way offhore etc.

cheers fnq

cheers fnq

[39NESP]

Why stop there?
If you fitted say a 140 hp motor you be able to plane, just, at full throttle, which could be very handy for short periods, eg. crossing a bar.
The rest of the time go easy at 8 knots with a very low reving motor to listen to.
do you think i would geton the plane with a 140 for i dont know
need help
thanks

[jimbo59]

A 50-60 would be a waste a 15 hp would do 8-10 knots.
A 50 or 60 would just burn fuel and the boat would not reach a planing speed.

[39NESP]

A 50-60 would be a waste a 15 hp would do 8-10 knots.
A 50 or 60 would just burn fuel and the boat would not reach a planing speed.


i have heard there is one lurking around the pin with a 50 merk on

doing about 12-14 knots

cheers

[jimbo59]

Yeah struggling to get up on the plane and burning 40 litres an hour.

[Crocodile]

I was on a 23 foot Stessl platey that was built to survey, heavy but not as heavy as a 23 Huntsman. Four adults, twin 85 Suzukis, I nagged the skipper into trying it on one motor. It did finally drag up onto the plane and got to 22knots on the speedo, all this at full throttle. If it had a correctly pitched prop it would have had much better accelaration. I wouldn't run a motor at full throttle for more than few minutes at a time but it would be OK to get out of trouble. The rest of the time it would be off-plane doing 8 knots or so. At 12 knots the planing hull would drag it's tail and be very unpleasent with poor visibilty, huge wash and massive fuel consumption.
I have been on a 23 Huntsman cabin cruiser with a 188 Mercruiser, it was OK when lightly loaded, but with 6 or 7 POB often needed full throttle to stay on the plane.
A 140hp outboard would be in between performance wise.
How do you intend to use this boat?

[Chimo]

Have you thought about a diesel outboard?

Plenty of push, you would carry the weight OK and probably very cheap to run.

There were a few around second hand if you have a hunt, pardon the pun.

Cheers
Chimo

maybe here http://regalmarine.boatpoint.com.au/boats-for-sale/details.aspx?R=5878996

[39NESP]

I was on a 23 foot Stessl platey that was built to survey, heavy but not as heavy as a 23 Huntsman. Four adults, twin 85 Suzukis, I nagged the skipper into trying it on one motor. It did finally drag up onto the plane and got to 22knots on the speedo, all this at full throttle. If it had a correctly pitched prop it would have had much better accelaration. I wouldn't run a motor at full throttle for more than few minutes at a time but it would be OK to get out of trouble. The rest of the time it would be off-plane doing 8 knots or so. At 12 knots the planing hull would drag it's tail and be very unpleasent with poor visibilty, huge wash and massive fuel consumption.
I have been on a 23 Huntsman cabin cruiser with a 188 Mercruiser, it was OK when lightly loaded, but with 6 or 7 POB often needed full throttle to stay on the plane.
A 140hp outboard would be in between performance wise.
How do you intend to use this boat?

just to get 9-10 knots over bottom the other power for just incase

cheers

[wayneoro]

i have also been trying to get info on this subject . 8kts is plenty of speed for me .if i can go from pt a to pt b and greatly cut my fuel bill . my boat 20ft glass . so what motor small -med 4 stroke ?

[on-one]

I can't help thinking you'd end up with a better boat for what you want to use it for, and it'd cost less in the long run, to sell the huntsman and buy something designed to do that speed like a longboat 21 or a nordic 23. An underpowered huntsman would be very hard to sell and as others have mentioned probably wouldn't be that nice to use.

[39NESP]

[quote=on-one;912711]I can't help thinking you'd end up with a better boat for what you want to use it for, and it'd cost less in the long run, to sell the huntsman and buy something designed to do that speed like a longboat 21 or a nordic 23. An underpowered huntsman would be very hard to sell and as others have mentioned probably wouldn't be that nice to use.[/qu

on-0ne. i have rebuilt the boat to our needs it now a full cabin walk through

as for resale not a isue as for retirment not for resale


cheers

[ozlongboarder]

I understand what your trying to do, if you do go with a small hp outboard make sure its a 4 stroke. These are numbers for a 25 Bertarm Flybridge fitted with a 225 Mariner Optimax that is on the 25 Bertram forum.


2 people on board, 40 gallons of fuel, light on gear.

RPM gauge GPS

1000rpm - 5.1mph
1500rpm - 6.0mph
2000rpm - 8.0mph
2500rpm - 8.5mph
3000rpm - 10.2mph Planes off a 3400 and will stay on plane at 3200
3500rpm - 24.1mph 3600rpm seems like the best cruise
3800rpm - 25.3mph
4000rpm - 28.0mph
4200rpm - 29.5mph
4500rpm - 31.7mph
4800rpm - 34.1mph
5350rpm - 38.6mph WOT

I still cant believe how great she runs. She is still very light and will a full load, I am sure that she will be 500lbs -800lbs heavier with normal load. I am sure it will be a 25mph cruise with a 36mph top end.

Single 225hp 30inch Optimax swinging a 15x15 Mirage Plus with one VPS hole out. Hole shot was great, 5-6 seconds to plane! At the dock, the lower unit bulb is 4 inches out of the water. The engine is tired and I am just hoping to get alittle more life out of it.

Her balance is perfect, she sit flat. She also sits very very light. I am estimating weight to be 4200lbs with engine and 40 gallons fuel. She has an 82 gallon tank, so an extra 260lbs of fuel will help.

[MarkDiver]

Can I suggest going to your local marine supplier/mechanic and having a chat as I've done in the past - they could offer you valuable advise but more importantly they often have spare props for you to trial before you commit to purchasing! I know two other blokes that also had props lent to them for trial purposes.

-edited: sorry i misread the question. Thought it was prop-related somehow :-[

[trev1]

I think if you were to power your boat correctly, and then just use the lower end of its speed range you would get the best fuel efficiency. It will mean a larger engine, but a big engine barely working will use less than a little one screwed to the limits. A diesel in/outdrive might be a viable option also, particularly if economy at the lower speeds matters.

[39NESP]

http://www.ausfish.com.au/vforum/00401shots of my boat

[39NESP]

more shots

[39NESP]

inside of boat

[gofishin]

...No matter what ensure it reaches the top of it's wot rpm... ...... 39N, take note, this is important, especially for the type of use you are talking about.

...At what speed do these thing start to drag their bum and point their nose up in the air? the spot where it leaves displacement mode and tries to plane... We can get a good idea from the figures ozlongboarder posted, when presented graphically. The 25 berty and 23 Huntsman were very similar shaped hulls; ~25 vs 23 deg deadrise, 9'6" vs 9'2" or 4" (from memory), and of course the length & weight difference. The Huntsman was a copy of the berty, on a slightly smaller scale.

...small hp 40hp? may get it there but to go much further you may need trebble...cheers fnq I would say you would be spot-on FNQ

Refer attached graph of the oz's figures. The transition speed (displacement to planing) starts before 10mph and continues to around 3400rpm (oz's notes for planing) @ approx 20mph (?). In other words, from somewhere before 10mph she will suck huge hp with not much gain in speed. (What we see in the speed vs rpm chart is somewhat the 'aftermath' of enterring the hump phase.)

To get in in perspective, at 4000rpm I would estimate the 225hp optimax would be producing approx 65% of max torque. At 3400rpm maybe approx 55%. That is significant hp to what we are talking about.


I was on a 23 foot Stessl platey that was built to survey, heavy but not as heavy as a 23 Huntsman. Four adults, twin 85 Suzukis, I nagged the skipper into trying it on one motor. It did finally drag up onto the plane and got to 22knots on the speedo, all this at full throttle....

There would be a significant difference in the boats due to the beam, deadrise and displacement of the two boats. Fatter boats are significantly harder to plane, regardless of deadrise, and the tinny would have had a lot less deadrise.

As other have suggested, talk to some O/B manufacturers & see what they say. I would be looking at 40 - 60hp in High Thrust models (if petrol), with High Thrust props. 40 would probably be ample, but maybe into a strong headwind (you have a high wind resistance) some extra hp would be beneficial. Check also diesel O/B as Chimo (?) suggested. They have been around for a very long time, but not sure of availability & sizes/suitability etc
cheers

[39NESP]

do you think trimtabs will help lift her stern
cheers

[gofishin]

Not at the speeds you are talking about. Unfortunately there is not a lot you can do to help your situation (planing hull used as a displacement hull), save for making a huge full width & depth pod/boarding platform, that sweeps up & moderates deadrise from both planing surfaces - thus changing the hull into a double ender! Would need to be approx 2m long too minimum, and would be quite expensive to build. Hmmm, that could turn ugly pretty easily. Stick with what you have, live with the compromise & enjoy boating

[Ian1]

Hi 39NESP

Looks like you have done some nice work to that boat.

I had a 23 Caribean Crusader which is very similar in weight and design to your Huntsman when it was original.

We had a 270 hp volvo and a 9.8 auxilary for poking around the remote creeks up in the Gulf for extended periods. The 9.8 would push it along at 5-6 knots max and about 4 knots cruise assuming there was no head wind or chop. And yes it was correctly propped. I think that rules out using a 15hp. You have to consider conditions are not allways going to be perfect and pushing a headwind and chop will kill a 15 hp on that boat.

The Carribean would start to lift the nose and drop its bum at anything over about 10 knots so I would say that is going to be your max cruise speed. As said previously anything over that requires much more power as the boat is trying to lift onto the plane. 8-9 knots will be much more efficeint then even 10kt let alone 12kt.

As for trim tabs we had the biggest tabs we could fit on the transome and I can assure you they will do nothing at the speeds you are looking at.

To sum up in my opinion I think you are on track with 50-60 hp. Personaly I wouldn't go any less but any more is going to be a waste.

Hope I could be of help.

cheers

Ian

[39NESP]

ian thanks very much for your advice
i have a 115 hp evinrude on my other boat that i want to try on this one
perhaps on low revs it might be alright
as for ex i was all ways in the dark 9.9 sounds fine
cheers snapper
ps please keep in touch

[Blaster Bretty]

39NESP!!! listen to "GOFISHIN" he has put a very worthy post for you.
In my opinion you should go for at least 100 + hp in the four stroke guise, this will give you the much broader range to use and economy to boot, the 4 stroke's dont mind at all cruising at a very low rev whereas the 2 stroke's carbon up somewhat if not wound out on a regular basis (I own a 40 2stk johnno myself) and try not to go for a 40-50 or even 60 odd HP because it is much better to have the extra horse's and not need them than to need the extra horse's and not have them....get my drift.
You never know when you will need the extra horse's to help you out of trouble and if youve got say a 140 4stk then you can still run it slow (with the correct prop) and use a modest amount of gas but if need be you can slam the throttle and get to land quick smart.

Bretty