Jet ski powered hydroplane

[rgardn12]

Alright I have a bit of a problem... I purchased a 1989 Ultranautics Jet ski with 60 hp suzuki motor in it... but it wasn't till I got home that I saw the massive crack in the hull that makes the jet ski itself useless.

I know that generally speaking hydroplanes are outboard propelled or use very small direct drive inboards, but given the shallow depth and low deadrise angle on both a jet ski and hydro-boats I thought it may be possible to design such a boat.

Does anyone know of any pre-existing plans for a 5' to 10' single seat hydro-boat that is powered by a jet ski motor?

[rasorinc]

https://www.boatdesigns.com/products.asp?dept=369 thay offer several other versions including true hydroplanes and you can adapt that engine/jet. All of their plans like this have been built and there is a lot of info on them. Here is another thought for you.https://www.boatdesigns.com/products.asp?dept=212 another. https://www.boatdesigns.com/products.asp?dept=340

[rgardn12]

... just looking at the specs for motors on these boats it seems one crucial problem will be the weight of the motor/jet drive combo and sheer size. I am wondering if it would be pointless to attempt. Even if I were to modify the existing motor to run without the jet drive the motors 60hp output far exceeds anything safe according to the site.

[rasorinc]

If there was a plan there you liked, tell me the weight of the engine/jet and I will take a look at it for you.

[rgardn12]

I like the 10' Tunnel Mite design, however I have yet to pull the motor/jet drive so I am unsure of the weight however the jet ski rated dry weight is 435lbs. its a 2 stroke 2 cylinder motor as well if that helps you est. the weight.

I am also kind of interested in the Tiny Titan... but I am interested in it because I would like to know if I could modify it to fit a inboard 5 to 10hp B&S motor that I could attach to a direct drive.

[rasorinc]

Here is another thought for you and would easily take your engine/jet.
https://www.boatdesigns.com/products.asp?dept=314
pics of a build of tiny mite enlarged.http://www.glen-l.com/picboards/picboard15/pic763a.html
http://www.glen-l.com/picboards/picboard7/pic441a.html

[rgardn12]

One of the goals for me is to attempt to build this boat for less than $250 to $300... I am attracted to hydros mainly because the ease of construction because of there simple shallow hulls. In comparison to the former hulls how expensive and complicated will the V-hull be to build?

I live near a 3000 acre lake which is where ill be running this boat and another question I've thought about is the possibility of having issues with even the slightest wake or chop. How great is the risk of capsizing thr form type hulls?

[rasorinc]

The CD monohull racing boat will be more stable than a hydroplane in wind driven or boat caused chop. A jet hydro is more stable then a prop driven one but they are mainly flat bottomed so they bounce up and down.
Keep in mind, it gets boring boating alone so I would encourage you to consider a 2 seater. Your budget is a little low but not by much if you work at it. You do not need to use mahogony to build it. Glen L lists boat building softwoods that are avaiable and you can use hot dip gavanized screws and bolts--not Bronze

[rgardn12]

so all in all... if I really wanted to I could probably construct either the Dyno Jet or the TNT for under $500?

how would I go about modifying the TNT design to fit a Jet Drive? I really like that hull better than the Dyno Jet, however the stitch and glue construction seems FAR easier when compared to standard plywood construction.

[rasorinc]

I would go with the Dyno Jet as it was designed to do exactly what you want to do. Epoxy is a must and I can give you a link that offers the best for the least. Consider buying the GlenL books Boatbuilding with Plywood and How to fiberglass Boats 2nd edition. Both are listed on the GlenL site anf you might find them used on Amazon.com. If you do a nice job you would only have to fiberglass the bottom and will save you $$. With careful shopping I will say YES you can do it for $500.00. The plans will cost you $100.00 with postage and the 2 books maybe $30.00 leaving $370.00 for materials. As I said, work hard, buy right and the answer is still YES. I will work with you as much as you need for advise on buying materials and building it but do not turn down any work to make a few extra bucks. Stan PS I would join the Glen-L forum if you go with their plans. Lots of help there. I built my 1st boat with Glen-L plans as a junior/senior in High School. It was the Flying Saucer and I cut out all the frames in Woodshop. The year was 1958/59 so now you know I'm old and have lots of experience. I'm buildeng 2 Glen-L boats right now. You can send me a private message or email from this site or the Glen-L forum. My user name is Rasorinc so if you deside to do it send me a PM and we will continue with details using that method. I have a son and daughter plus two grand children in Knoxville, Tenn. How close is that to you?

If one out there wants my opinion?
`cos till now it was a dialogue only.

Go for the Dyno Jet, it is already what you need and has nothing to be "redesigned". That always causes hefty trouble if done by a novice (and professional assistance is ten times the plans price).
Go with a Forum like this (is not the only one existing although the most professional), and make it a "online happening" so, all of us can contribute, criticise and assist. You´ll be impressed how much money one can save if the whole community is part of the game.
Stan has lead you to the right paths already, so you should choose him as your mentor.
If any stuff is to choose or to buy, ask first!!! There are always some valuable comments and hints. And unfortunately sometimes just idiotic comments as well. Stand it, it makes you wiser and patient. (did not function with me though)

Regards
Richard

[rgardn12]

Thank you guys very much.. I have a lot to consider and I appreciate all the advice. I am going to soon check and see if the Motor/Jet Drive is fully capable of running as the seller said, but after speaking with a friend about the condition of the spark plugs and given the sellers reputation for lying already I am kind of weary that it will run.

However, if it will not run I am hoping to build a Glen-L outboard design anyway... probably either the TNT or Dyno Mite... leaning towards Dyno Mite since its Stitch and Glue. Maybe in the future I'll work on the Tiny Titan just for fun on the flat days

Stan, question in your experience is it easier to construct a Stitch and Glue boat or traditional built boat? And what kind of woods that are good for boat building are available in mass quantities are available in the southeast? as I live in Charlotte, NC and Knoxville is about 230 mi away from charlotte.

Although the question was addressed to Stan,

there is no difference between stitch an glue and conventional (strip plank) methods. Both have their disadvantages. But a strip plank boat can get much nicer in the end than a st+g.

Regards
Richard

[rgardn12]

I was asking in general but since I knew he had been replying I figured I would address him, but thank you for the reply.

As far as time for construction goes... which would be faster? S+G or traditional? I am just trying to understand which would be the more efficient way for a new builder to tackle his first project.

S+G is faster only from the first glimpse. Strip plank is slower to understand to be fast, but as fast to build (the second build is faster than s+g will be possible).